docs(browser): fix layer rules — renderer/dom is integration, not platform

Co-authored-by: Daniel Imms <Tyriar@users.noreply.github.com>

.gitignore

@@ -24,6 +24,7 @@ test-results/
 
 # Tracing/debug files
 .cursor/nal-trace/
+.cursor/*.log
 
 # Keep bundled code out of Git
 dist/

AGENTS.md

@@ -98,3 +98,15 @@ const cell = line?.getCell(0);
 ## Writing unit tests
 
 - Unit tests live alongside the source code file of the thing it's testing with a .test.ts suffix.
+
+## Cursor Cloud specific instructions
+
+**Demo server**: Start with `npm start` (port 3000). The demo server uses node-pty to spawn real shell sessions over WebSocket. Integration tests auto-start it via Playwright's `webServer` config, so you don't need to start it manually for `npm run test-integration`.
+
+**Build before testing**: Always run `npm run build && npm run esbuild` before `npm run test-unit`. Integration tests also need `npm run esbuild-demo-client` and `npm run esbuild-demo-server`. The update script handles this automatically on session start.
+
+**No external services**: This project has zero external dependencies (no databases, Docker, or APIs). Everything runs locally with Node.js.
+
+**TypeScript compiler**: The project uses `tsgo` (native TypeScript compiler preview) rather than standard `tsc`. It's installed via the `@typescript/native-preview` package.
+
+**Lint only changed files**: Prefer `npm run lint-changes` over `npm run lint` when iterating on code changes — it's significantly faster.

addons/addon-image/README.md

@@ -1,6 +1,7 @@
 ## @xterm/addon-image
 
-Inline image output in xterm.js. Supports SIXEL and iTerm's inline image protocol (IIP).
+Inline image output in xterm.js. Supports SIXEL, iTerm's inline image protocol (IIP)
+and partially Kitty's terminal graphics prtocol (TGP).
 
 
 ![](fixture/example.png)
@@ -43,9 +44,6 @@ terminal.loadAddon(imageAddon);
 
 ### General Notes
 
-- *IMPORTANT:* The worker approach as done in previous releases got removed.
-  The addon contructor no longer expects a worker path as first argument.
-
 - By default the addon will activate these `windowOptions` reports on the terminal:
   - getWinSizePixels (CSI 14 t)
   - getCellSizePixels (CSI 16 t)
@@ -73,7 +71,7 @@ terminal.loadAddon(imageAddon);
 
 - **Cursor Positioning**  
   If scrolling is set, the cursor will be placed at the first image column of the last image row (VT340 mode).
-  Other cursor positioning modes as used by xterm or mintty are not supported.
+  Other cursor positioning modes as used by xterm or mintty are not supported for sixel.
 
 - **SIXEL Palette Handling**  
   By default the addon limits the palette size to 256 registers (as demanded by the DEC specification).
@@ -100,17 +98,24 @@ terminal.loadAddon(imageAddon);
   Set by default, change it with `{iipSupport: true}`.
 
   The IIP implementation has the following features / restrictions (sequence will silently fail for unmet conditions):
-  - Supported formats: PNG, JPEG and GIF
+  - Supported formats: PNG, JPEG, GIF and QOI
   - No animation support.
   - Image type hinting is not supported (always deducted from data header).
   - File download is not supported.
   - Filename gets parsed but not used.
   - Strict base64 handling as of RFC4648 §4 (standard alphabet, optional padding, no separator bytes allowed).
-  - Payload size may not exceed CEIL(sizeParameter * 4 / 3).
   - Image scaling beyond terminal viewport size is allowed (e.g. `width=200%`).
   - Image pixel size is restricted by `pixelLimit` (pre- and post resizing).
-  - Size parameter is restricted by `iipSizeLimit`.
-  - Cursor positioning behaves the same as for sixel (see above).
+  - Playload size is restricted by `iipSizeLimit`.
+  - size parameter is not mandatory anymore.
+  - Cursor gets positioned at the next cell of the last image line.
+  - ReportCellSize sequence is supported.
+  - Hi-res display support is currently limited (image gets blurred).
+
+- **Kitty Graphics Support (TGP)**  
+  Set by default, change it with `{kittySupport: true}`.
+
+  Note that the kitty graphics support is still WIP.
 
 
 ### Storage and Drawing Settings
@@ -127,6 +132,7 @@ The addon exposes two properties to interact with the storage limits at runtime:
 By default the addon will show a placeholder pattern for evicted images that are still part
 of the terminal (e.g. in the scrollback). The pattern can be deactivated by toggling `showPlaceholder`.
 
+
 ### Image Data Retrieval
 
 The addon provides the following API endpoints to retrieve raw image data as canvas:
@@ -140,6 +146,7 @@ The addon provides the following API endpoints to retrieve raw image data as can
   The buffer position is the 0-based absolute index (including scrollback at top).
   Note that the canvas gets created and data copied over for every call, thus it is not suitable for performance critical actions.
 
+
 ### Memory Usage
 
 The addon does most image processing in Javascript and therefore can occupy a rather big amount of memory. To get an idea where the memory gets eaten, lets look at the data flow and processing steps:
@@ -180,8 +187,8 @@ _How can I adjust the memory usage?_
   A constructor setting, thus you would have to anticipate, whether (multiple) terminals in your page gonna do lots of concurrent decoding. Since this is normally not the case and the memory usage is only temporarily peaking, a rather high value should work even with multiple terminals in one page.
 - `storageLimit`  
   A constructor and a runtime setting. In conjunction with `storageUsage` you can do runtime checks and adjust the limit to your needs. If you have to lower the limit below the current usage, images will be removed in FIFO order and may turn into a placeholder in the terminal's scrollback (if `showPlaceholder` is set). When adjusting keep in mind to leave enough room for memory peaking for decoding.
-- `sixelSizeLimit`  
-  A constructor setting. This has only a small impact on peaking memory during decoding. It is meant to avoid processing of overly big or broken SIXEL sequences at an earlier phase, thus may stop the decoder from entering its memory intensive task for potentially invalid data.
+- `sixelSizeLimit | iipSizeLimit | kittySizeLimit`  
+  Constructor settings. This has only a small impact on peaking memory during decoding. It is meant to avoid processing of overly big or broken image sequences at an earlier phase, thus may stop the invoked decoders from entering memory intensive tasks for potentially invalid data.
 
 
 ### Terminal Interaction
@@ -211,23 +218,5 @@ _How can I adjust the memory usage?_
 
 ### Status
 
-- Sixel support and image handling in xterm.js is considered beta quality.
-- IIP support is in alpha stage. Please file a bug for any awkwardities.
-
-
-### Changelog
-
-- 0.5.0 integrate with xtermjs base repo (at v0.4.3)
-- 0.4.3 defer canvas creation
-- 0.4.2 fix image canvas resize
-- 0.4.1 compat release for xterm.js 5.2.0
-- 0.4.0 IIP support
-- 0.3.1 compat release for xterm.js 5.1.0
-- 0.3.0 important change: worker removed from addon
-- 0.2.0 compat release for xterm.js 5.0.0
-- 0.1.3 bugfix: avoid striping
-- 0.1.2 bugfix: reset clear flag
-- 0.1.1 bugfixes:
-  - clear sticky image tiles on render
-  - create folder from bootstrap.sh
-  - fix peer dependency in package.json
+- Sixel and IIP support and image handling in xterm.js is considered beta quality.
+- Kitty support is in alpha stage. Please file a bug for any awkwardities or missing features.

addons/addon-image/src/IIPHandler.ts

@@ -8,7 +8,7 @@ import { IIPImageStorage } from './IIPImageStorage';
 import { CELL_SIZE_DEFAULT } from './ImageStorage';
 import Base64Decoder from 'xterm-wasm-parts/lib/base64/Base64Decoder.wasm';
 import QoiDecoder from 'xterm-wasm-parts/lib/qoi/QoiDecoder.wasm';
-import { HeaderParser, IHeaderFields, HeaderState } from './IIPHeaderParser';
+import { HeaderParser, IHeaderFields, HeaderState, SequenceType } from './IIPHeaderParser';
 import { imageType, UNSUPPORTED_TYPE } from './IIPMetrics';
 
 // Local const enum mirror - esbuild can't inline const enums from external packages
@@ -23,6 +23,7 @@ const enum DecoderConst {
 
 // default IIP header values
 const DEFAULT_HEADER: IHeaderFields = {
+  type: SequenceType.INVALID,
   name: 'Unnamed file',
   size: 0,
   width: 'auto',
@@ -39,6 +40,8 @@ export class IIPHandler implements IOscHandler, IResetHandler {
   private _dec: Base64Decoder;
   private _qoiDec: QoiDecoder;
   private _metrics = UNSUPPORTED_TYPE;
+  private _isMultipart = false;
+  private _abortMulti = false;
 
   constructor(
     private readonly _opts: IImageAddonOptions,
@@ -52,11 +55,14 @@ export class IIPHandler implements IOscHandler, IResetHandler {
     this._qoiDec = new QoiDecoder(DecoderConst.KEEP_DATA);
   }
 
-  public reset(): void {}
+  public reset(): void {
+    this._hp.reset();
+    this._dec.release();
+    this._qoiDec.release();
+  }
 
   public start(): void {
     this._aborted = false;
-    this._header = DEFAULT_HEADER;
     this._metrics  = UNSUPPORTED_TYPE;
     this._hp.reset();
   }
@@ -76,15 +82,27 @@ export class IIPHandler implements IOscHandler, IResetHandler {
         return;
       }
       if (dataPos > 0) {
-        this._header = Object.assign({}, DEFAULT_HEADER, this._hp.fields);
-        if (!this._header.inline || !this._header.size || this._header.size > this._opts.iipSizeLimit) {
+        const seqType = this._hp.fields.type;
+        if (seqType === SequenceType.FILE) {
+          if (this._isMultipart) {
+            this._isMultipart = false;
+            this._abortMulti = false;
+            this._dec.release();
+          }
+          this._header = Object.assign({}, DEFAULT_HEADER, this._hp.fields);
+          if (!this._header.inline) {
+            this._aborted = true;
+            return;
+          }
+          this._dec.init();
+        } else if (this._abortMulti) {
           this._aborted = true;
           return;
         }
-        this._dec.init();
         if ((this._dec.put(data.subarray(dataPos, end)) as number) !== DecoderConst.OK) {
           this._dec.release();
           this._aborted = true;
+          if (this._isMultipart) this._abortMulti = true;
         }
       }
     }
@@ -93,22 +111,58 @@ export class IIPHandler implements IOscHandler, IResetHandler {
   public end(success: boolean): boolean | Promise<boolean> {
     if (this._aborted) return true;
 
+    if (this._hp.state !== HeaderState.END) {
+      if (this._hp.end()) return true;
+    }
+    const seqType = this._hp.fields.type;
+
+    if (seqType === SequenceType.FILEPART) return true;
+
+    if (seqType === SequenceType.REPORTCELLSIZE) {
+      // OSC 1337 ; ReportCellSize=[height];[width];[scale] ST
+      let width = CELL_SIZE_DEFAULT.width;
+      let height = CELL_SIZE_DEFAULT.height;
+      if (this._renderer.dimensions) {
+        width = this._renderer.dimensions.css.canvas.width / this._coreTerminal.cols;
+        height = this._renderer.dimensions.css.canvas.height / this._coreTerminal.rows;
+      }
+      const scale = this._coreTerminal._core._coreBrowserService?.dpr ?? 1;
+      const report = `\x1b]1337;ReportCellSize=${height.toFixed(3)};${width.toFixed(3)};${scale.toFixed(3)}\x1b\\`;
+      this._coreTerminal.input(report, false);
+      return true;
+    }
+
+    if (seqType === SequenceType.MULTIPARTFILE) {
+      this._header = Object.assign({}, DEFAULT_HEADER, this._hp.fields);
+      this._isMultipart = true;
+      this._abortMulti = false;
+      this._dec.release();
+      this._dec.init();
+      return true;
+    }
+
+    if (seqType === SequenceType.FILEEND) {
+      if (!this._isMultipart) return true;
+      this._isMultipart = false;
+      if (this._abortMulti || this._header.type !== SequenceType.MULTIPARTFILE) return true;
+    }
+
+    // fallthrough for SequenceType.FILE & SequenceType.FILEEND
+
     let w = 0;
     let h = 0;
 
     // early exit condition chain
-    let cond: number | boolean = true;
+    let cond: number | boolean;
     if (cond = success) {
       if (cond = !this._dec.end()) {
-        if (cond = this._dec.data8.length === this._header.size) {
-          this._metrics = imageType(this._dec.data8);
-          if (cond = this._metrics.mime !== 'unsupported') {
-            w = this._metrics.width;
-            h = this._metrics.height;
-            if (cond = w && h && w * h < this._opts.pixelLimit) {
-              [w, h] = this._resize(w, h).map(Math.floor);
-              cond = w && h && w * h < this._opts.pixelLimit;
-            }
+        this._metrics = imageType(this._dec.data8);
+        if (cond = this._metrics.mime !== 'unsupported') {
+          w = this._metrics.width;
+          h = this._metrics.height;
+          if (cond = w && h && w * h < this._opts.pixelLimit) {
+            [w, h] = this._resize(w, h).map(Math.floor);
+            cond = w && h && w * h < this._opts.pixelLimit;
           }
         }
       }

addons/addon-image/src/IIPHeaderParser.test.ts

@@ -4,19 +4,20 @@
  */
 
 import { assert } from 'chai';
-import { HeaderParser, HeaderState, IHeaderFields } from './IIPHeaderParser';
+import { HeaderParser, HeaderState, IHeaderFields, SequenceType } from './IIPHeaderParser';
 
 
 const CASES: [string, IHeaderFields][] = [
-  ['File=size=123456;name=dGVzdA==:', {name: 'test', size: 123456}],
-  ['File=size=123456;name=dGVzdA:', {name: 'test', size: 123456}],
+  ['File=size=123456;name=dGVzdA==:', {type: SequenceType.FILE, name: 'test', size: 123456}],
+  ['File=size=123456;name=dGVzdA:', {type: SequenceType.FILE, name: 'test', size: 123456}],
   // utf-8 encoding in name
-  ['File=size=123456;name=w7xtbMOkdXTDnw==:', {name: 'ümläutß', size: 123456}],
-  ['File=size=123456;name=w7xtbMOkdXTDnw:', {name: 'ümläutß', size: 123456}],
+  ['File=size=123456;name=w7xtbMOkdXTDnw==:', {type: SequenceType.FILE, name: 'ümläutß', size: 123456}],
+  ['File=size=123456;name=w7xtbMOkdXTDnw:', {type: SequenceType.FILE, name: 'ümläutß', size: 123456}],
   // full header spec
   [
     'File=inline=1;width=10px;height=20%;preserveAspectRatio=1;size=123456;name=w7xtbMOkdXTDnw:',
     {
+      type: SequenceType.FILE,
       inline: 1,
       width: '10px',
       height: '20%',
@@ -28,6 +29,7 @@ const CASES: [string, IHeaderFields][] = [
   [
     'File=inline=1;width=auto;height=20;preserveAspectRatio=1;size=123456;name=w7xtbMOkdXTDnw:',
     {
+      type: SequenceType.FILE,
       inline: 1,
       width: 'auto',
       height: '20',
@@ -101,7 +103,7 @@ describe('IIPHeaderParser', () => {
     let res = hp.parse(inp, 0, inp.length);
     assert.strictEqual(res, inp.length);
     assert.strictEqual(hp.state, HeaderState.END);
-    assert.deepEqual(hp.fields, {name: 'test', size: 0});
+    assert.deepEqual(hp.fields, {type: SequenceType.FILE, name: 'test', size: 0});
     hp.reset();
     inp = fromBs(CASES[0][0]);
     res = hp.parse(inp, 0, inp.length);
@@ -115,7 +117,7 @@ describe('IIPHeaderParser', () => {
     let res = hp.parse(inp, 0, inp.length);
     assert.strictEqual(res, inp.length);
     assert.strictEqual(hp.state, HeaderState.END);
-    assert.deepEqual(hp.fields, {name: '', size: 123456});
+    assert.deepEqual(hp.fields, {type: SequenceType.FILE, name: '', size: 123456});
     hp.reset();
     inp = fromBs(CASES[0][0]);
     res = hp.parse(inp, 0, inp.length);
@@ -135,4 +137,124 @@ describe('IIPHeaderParser', () => {
     assert.strictEqual(hp.state, HeaderState.END);
     assert.deepEqual(hp.fields, CASES[0][1]);
   });
+  it('FilePart sequence', () => {
+    const hp = new HeaderParser();
+    const inp = fromBs('FilePart=w7xtbMOkdXTDnw');
+    const res = hp.parse(inp, 0, inp.length);
+    assert.strictEqual(res, 9);
+    assert.strictEqual(hp.state, HeaderState.END);
+    assert.deepEqual(hp.fields.type, SequenceType.FILEPART);
+  });
+  it('FilePart sequence - bytewise', () => {
+    const hp = new HeaderParser();
+    const inp = fromBs('FilePart=w7xtbMOkdXTDnw');
+    let res = -2;
+    let pos = 0;
+    while (res === -2 && pos < inp.length) {
+      res = hp.parse(new Uint32Array([inp[pos++]]), 0, 1);
+    }
+    assert.strictEqual(res, 1);
+    assert.strictEqual(hp.state, HeaderState.END);
+    assert.deepEqual(hp.fields.type, SequenceType.FILEPART);
+  });
+  it('MultipartFile sequence', () => {
+    const hp = new HeaderParser();
+    const inp = fromBs('MultipartFile=inline=1;width=10px;height=20%;preserveAspectRatio=1;size=123456;name=w7xtbMOkdXTDnw');
+    let res = hp.parse(inp, 0, inp.length);
+    assert.strictEqual(res, -2);
+    assert.strictEqual(hp.state, HeaderState.VALUE);
+    res = hp.end();
+    assert.strictEqual(res, 0);
+    assert.strictEqual(hp.state, HeaderState.END);
+    assert.deepEqual(
+      hp.fields,
+      {
+        type: SequenceType.MULTIPARTFILE,
+        inline: 1,
+        width: '10px',
+        height: '20%',
+        preserveAspectRatio: 1,
+        size: 123456,
+        name: 'ümläutß'
+      }
+    );
+  });
+  it('MultipartFile sequence - bytewise', () => {
+    const hp = new HeaderParser();
+    const inp = fromBs('MultipartFile=inline=1;width=10px;height=20%;preserveAspectRatio=1;size=123456;name=w7xtbMOkdXTDnw');
+    let res = -2;
+    let pos = 0;
+    while (res === -2 && pos < inp.length) {
+      res = hp.parse(new Uint32Array([inp[pos++]]), 0, 1);
+    }
+    assert.strictEqual(res, -2);
+    assert.strictEqual(hp.state, HeaderState.VALUE);
+    res = hp.end();
+    assert.strictEqual(res, 0);
+    assert.strictEqual(hp.state, HeaderState.END);
+    assert.deepEqual(
+      hp.fields,
+      {
+        type: SequenceType.MULTIPARTFILE,
+        inline: 1,
+        width: '10px',
+        height: '20%',
+        preserveAspectRatio: 1,
+        size: 123456,
+        name: 'ümläutß'
+      }
+    );
+  });
+  it('FileEnd sequence', () => {
+    const hp = new HeaderParser();
+    const inp = fromBs('FileEnd');
+    let res = hp.parse(inp, 0, inp.length);
+    assert.strictEqual(res, -2);
+    assert.strictEqual(hp.state, HeaderState.START);
+    res = hp.end();
+    assert.strictEqual(res, 0);
+    assert.strictEqual(hp.state, HeaderState.END);
+    assert.deepEqual(hp.fields.type, SequenceType.FILEEND);
+  });
+  it('FileEnd sequence - bytewise', () => {
+    const hp = new HeaderParser();
+    const inp = fromBs('FileEnd');
+    let res = -2;
+    let pos = 0;
+    while (res === -2 && pos < inp.length) {
+      res = hp.parse(new Uint32Array([inp[pos++]]), 0, 1);
+    }
+    assert.strictEqual(res, -2);
+    assert.strictEqual(hp.state, HeaderState.START);
+    res = hp.end();
+    assert.strictEqual(res, 0);
+    assert.strictEqual(hp.state, HeaderState.END);
+    assert.deepEqual(hp.fields.type, SequenceType.FILEEND);
+  });
+  it('ReportCellSize sequence', () => {
+    const hp = new HeaderParser();
+    const inp = fromBs('ReportCellSize');
+    let res = hp.parse(inp, 0, inp.length);
+    assert.strictEqual(res, -2);
+    assert.strictEqual(hp.state, HeaderState.START);
+    res = hp.end();
+    assert.strictEqual(res, 0);
+    assert.strictEqual(hp.state, HeaderState.END);
+    assert.deepEqual(hp.fields, { type: SequenceType.REPORTCELLSIZE });
+  });
+  it('ReportCellSize sequence - bytewise', () => {
+    const hp = new HeaderParser();
+    const inp = fromBs('ReportCellSize');
+    let res = -2;
+    let pos = 0;
+    while (res === -2 && pos < inp.length) {
+      res = hp.parse(new Uint32Array([inp[pos++]]), 0, 1);
+    }
+    assert.strictEqual(res, -2);
+    assert.strictEqual(hp.state, HeaderState.START);
+    res = hp.end();
+    assert.strictEqual(res, 0);
+    assert.strictEqual(hp.state, HeaderState.END);
+    assert.deepEqual(hp.fields, { type: SequenceType.REPORTCELLSIZE });
+  });
 });

addons/addon-image/src/IIPHeaderParser.ts

@@ -6,9 +6,27 @@
 // eslint-disable-next-line
 declare const Buffer: any;
 
+export const enum HeaderState {
+  START = 0,
+  ABORT = 1,
+  KEY = 2,
+  VALUE = 3,
+  END = 4
+}
+
+export const enum SequenceType {
+  INVALID = 0,
+  FILE = 1,
+  MULTIPARTFILE = 2,
+  FILEPART = 3,
+  FILEEND = 4,
+  REPORTCELLSIZE = 5
+}
 
 export interface IHeaderFields {
   [key: string]: number | string | Uint32Array | null | undefined;
+  // sequence type
+  type: SequenceType;
   // base-64 encoded filename. Defaults to "Unnamed file".
   name: string;
   // File size in bytes. The file transfer will be canceled if this size is exceeded.
@@ -29,14 +47,6 @@ export interface IHeaderFields {
   inline?: number;
 }
 
-export const enum HeaderState {
-  START = 0,
-  ABORT = 1,
-  KEY = 2,
-  VALUE = 3,
-  END = 4
-}
-
 // field value decoders
 
 // ASCII bytes to string
@@ -92,7 +102,19 @@ const DECODERS: {[key: string]: (v: Uint32Array) => number | string} = {
 };
 
 
+// sequence type markers
+// File
 const FILE_MARKER = [70, 105, 108, 101];
+// MultipartFile
+const MULTIPARTFILE_MARKER = [77, 117, 108, 116, 105, 112, 97, 114, 116, 70, 105, 108, 101];
+// FilePart
+const FILEPART_MARKER = [70, 105, 108, 101, 80, 97, 114, 116];
+// FileEnd
+const FILEEND_MARKER = [70, 105, 108, 101, 69, 110, 100];
+// ReportCellSize
+const REPORTCELLSIZE_MARKER = [82, 101, 112, 111, 114, 116, 67, 101, 108, 108, 83, 105, 122, 101];
+
+// max allowed chars for sequence header
 const MAX_FIELDCHARS = 1024;
 
 
@@ -111,12 +133,43 @@ export class HeaderParser {
     this._key = '';
   }
 
+  public end(): number {
+    if (this.state === HeaderState.START) {
+      if (this._position === FILEEND_MARKER.length) {
+        for (let k = 0; k < FILEEND_MARKER.length; ++k) {
+          if (this._buffer[k] !== FILEEND_MARKER[k]) return this._a();
+        }
+        this.fields['type'] = SequenceType.FILEEND;
+        this.state = HeaderState.END;
+        return 0;
+      }
+      if (this._position === REPORTCELLSIZE_MARKER.length) {
+        for (let k = 0; k < REPORTCELLSIZE_MARKER.length; ++k) {
+          if (this._buffer[k] !== REPORTCELLSIZE_MARKER[k]) return this._a();
+        }
+        this.fields['type'] = SequenceType.REPORTCELLSIZE;
+        this.state = HeaderState.END;
+        return 0;
+      }
+      return this._a();
+    }
+    if (this.state === HeaderState.END) return 0;
+    if (this.state === HeaderState.VALUE
+      && this.fields.type === SequenceType.MULTIPARTFILE
+    ) {
+      if (!this._storeValue(this._position)) return this._a();
+      this.state = HeaderState.END;
+      return 0;
+    }
+    return this._a();
+  }
+
   public parse(data: Uint32Array, start: number, end: number): number {
     let state = this.state;
     let pos = this._position;
     const buffer = this._buffer;
     if (state === HeaderState.ABORT || state === HeaderState.END) return -1;
-    if (state === HeaderState.START && pos > 6) return -1;
+    if (state === HeaderState.START && pos > 14) return -1;
     for (let i = start; i < end; ++i) {
       const c = data[i];
       switch (c) {
@@ -127,8 +180,29 @@ export class HeaderParser {
           break;
         case 61: // =
           if (state === HeaderState.START) {
-            for (let k = 0; k < FILE_MARKER.length; ++k) {
-              if (buffer[k] !== FILE_MARKER[k]) return this._a();
+            if (buffer[0] === 70) {
+              // 'File' or 'FilePart'
+              let k = 0;
+              for (; k < FILE_MARKER.length; ++k) {
+                if (buffer[k] !== FILE_MARKER[k]) return this._a();
+              }
+              this.fields['type'] = SequenceType.FILE;
+              if (pos === FILEPART_MARKER.length) {
+                for (; k < FILEPART_MARKER.length; ++k) {
+                  if (buffer[k] !== FILEPART_MARKER[k]) return this._a();
+                }
+                this.fields['type'] = SequenceType.FILEPART;
+                this.state = HeaderState.END;
+                return i + 1;
+              }
+            } else if (buffer[0] === 77) {
+              // 'MultipartFile'
+              for (let k = 0; k < MULTIPARTFILE_MARKER.length; ++k) {
+                if (buffer[k] !== MULTIPARTFILE_MARKER[k]) return this._a();
+              }
+              this.fields['type'] = SequenceType.MULTIPARTFILE;
+            } else {
+              return this._a();
             }
             state = HeaderState.KEY;
             pos = 0;
@@ -158,6 +232,7 @@ export class HeaderParser {
   }
 
   private _a(): number {
+    this.fields.type = SequenceType.INVALID;
     this.state = HeaderState.ABORT;
     return -1;
   }

addons/addon-image/src/IIPImageStorage.ts

@@ -3,6 +3,7 @@
  * @license MIT
  */
 
+import { IAddImageOpts } from 'Types';
 import { ImageStorage } from './ImageStorage';
 
 /**
@@ -12,6 +13,7 @@ import { ImageStorage } from './ImageStorage';
  * - Always uses scrolling mode (cursor advances with image)
  */
 export class IIPImageStorage {
+  private _addImageOpts: IAddImageOpts = { scrolling: true, layer: 'top', zIndex: 0, cursorPos: 'iip' };
   constructor(
     private readonly _storage: ImageStorage
   ) {}
@@ -21,6 +23,6 @@ export class IIPImageStorage {
    * Always uses scrolling mode — cursor advances past the image.
    */
   public addImage(img: HTMLCanvasElement | ImageBitmap): void {
-    this._storage.addImage(img, true);
+    this._storage.addImage(img, this._addImageOpts);
   }
 }

addons/addon-image/src/IIPMetrics.test.ts

@@ -30,7 +30,8 @@ const TEST_IMAGES: [string, IMetrics][] = [
   ['iphone_hdr_YES.jpg', { mime: 'image/jpeg', width: 3264, height: 2448 }],
   ['nikon-e950.jpg', { mime: 'image/jpeg', width: 800, height: 600 }],
   ['agfa-makernotes.jpg', { mime: 'image/jpeg', width: 8, height: 8 }],
-  ['sony-alpha-6000.jpg', { mime: 'image/jpeg', width: 6000, height: 4000 }]
+  ['sony-alpha-6000.jpg', { mime: 'image/jpeg', width: 6000, height: 4000 }],
+  ['dice.qoi', { mime: 'image/qoi', width: 800, height: 600 }],
 ];
 
 

addons/addon-image/src/ImageAddon.ts

@@ -137,11 +137,6 @@ export class ImageAddon implements ITerminalAddon, IImageApi {
 
     // enable size reports
     if (this._opts.enableSizeReports) {
-      // const windowOptions = terminal.getOption('windowOptions');
-      // windowOptions.getWinSizePixels = true;
-      // windowOptions.getCellSizePixels = true;
-      // windowOptions.getWinSizeChars = true;
-      // terminal.setOption('windowOptions', windowOptions);
       const windowOps = terminal.options.windowOptions ?? {};
       windowOps.getWinSizePixels = true;
       windowOps.getCellSizePixels = true;
@@ -260,7 +255,7 @@ export class ImageAddon implements ITerminalAddon, IImageApi {
   }
 
   private _report(s: string): void {
-    this._terminal?._core.coreService.triggerDataEvent(s);
+    this._terminal?._core.input(s, false);
   }
 
   private _decset(params: (number | number[])[]): boolean {

addons/addon-image/src/ImageRenderer.ts

@@ -146,7 +146,7 @@ export class ImageRenderer extends Disposable implements IDisposable {
   public clearLines(start: number, end: number, layer?: ImageLayer): void {
     const y = start * (this.dimensions?.css.cell.height || 0);
     const w = this.dimensions?.css.canvas.width || 0;
-    const h = (++end - start) * (this.dimensions?.css.cell.height || 0);
+    const h = (end + 1 - start) * (this.dimensions?.css.cell.height || 0);
     if (!layer || layer === 'top') {
       this._layers.get('top')?.clearRect(0, y, w, h);
     }

addons/addon-image/src/ImageStorage.ts

@@ -5,7 +5,11 @@
 
 import { IDisposable } from '@xterm/xterm';
 import { ImageRenderer } from './ImageRenderer';
-import { ITerminalExt, IExtendedAttrsImage, IImageAddonOptions, IImageSpec, IBufferLineExt, BgFlags, Cell, Content, ICellSize, ExtFlags, Attributes, UnderlineStyle, ImageLayer } from './Types';
+import {
+  ITerminalExt, IExtendedAttrsImage, IImageAddonOptions, IImageSpec,
+  IBufferLineExt, BgFlags, Cell, Content, ICellSize, ExtFlags, Attributes,
+  UnderlineStyle, IAddImageOpts
+} from './Types';
 
 
 // fallback default cell size
@@ -235,13 +239,15 @@ export class ImageStorage implements IDisposable {
   /**
    * Method to add an image to the storage.
    * @param img - The image to add (canvas or bitmap).
-   * @param scrolling - When true, cursor advances with the image (lineFeed per row).
-   *   When false, image is placed at (0,0) and cursor is restored (DECSET 80 / sixel origin mode).
-   * @param layer - Which canvas layer to render on ('top' or 'bottom').
-   * @param zIndex - Z-index for image layering within the same layer.
+   * @param opts - Options for addImage:
+   *   - scrolling:  When true, cursor advances with the image.
+   *                 When false, image is placed at ORIGIN and cursor does not move.
+   *   - layer:      Which canvas layer to render on ('top' or 'bottom').
+   *   - zIndex:     Z-index for image layering within the same layer.
+   *   - cursorPos:  'vt340' for bottom-left, 'iip' for bottom.right.
    * @returns The internal image ID assigned to the stored image.
    */
-  public addImage(img: HTMLCanvasElement | ImageBitmap, scrolling: boolean, layer: ImageLayer = 'top', zIndex: number = 0): number {
+  public addImage(img: HTMLCanvasElement | ImageBitmap, opts: IAddImageOpts): number {
     // never allow storage to exceed memory limit
     this._evictOldest(img.width * img.height);
 
@@ -263,7 +269,7 @@ export class ImageStorage implements IDisposable {
     let offset = originX;
     let tileCount = 0;
 
-    if (!scrolling) {
+    if (!opts.scrolling) {
       buffer.x = 0;
       buffer.y = 0;
       offset = 0;
@@ -277,7 +283,7 @@ export class ImageStorage implements IDisposable {
         this._writeToCell(line as IBufferLineExt, offset + col, imageId, row * cols + col);
         tileCount++;
       }
-      if (scrolling) {
+      if (opts.scrolling) {
         if (row < rows - 1) this._terminal._core._inputHandler.lineFeed();
       } else {
         if (++buffer.y >= termRows) break;
@@ -287,8 +293,12 @@ export class ImageStorage implements IDisposable {
     this._terminal._core._inputHandler._dirtyRowTracker.markDirty(buffer.y);
 
     // cursor positioning modes
-    if (scrolling) {
-      buffer.x = offset;
+    if (opts.scrolling) {
+      if (opts.cursorPos === 'iip') {
+        buffer.x = Math.min(offset + cols, termCols);
+      } else {
+        buffer.x = offset;
+      }
     } else {
       buffer.x = originX;
       buffer.y = originY;
@@ -331,8 +341,8 @@ export class ImageStorage implements IDisposable {
       marker: endMarker || undefined,
       tileCount,
       bufferType: this._terminal.buffer.active.type,
-      layer,
-      zIndex
+      layer: opts.layer,
+      zIndex: opts.zIndex
     };
 
     // finally add the image
@@ -455,7 +465,6 @@ export class ImageStorage implements IDisposable {
             if (!nextE || nextE.imageId !== imageId || nextE.tileId !== startTile + count) {
               break;
             }
-            e = nextE;
             count++;
           }
           col--;

addons/addon-image/src/SixelHandler.ts

@@ -91,7 +91,7 @@ export class SixelHandler implements IDcsHandler, IResetHandler {
     const height = this._dec.height;
 
     // partial fix for https://github.com/jerch/xterm-addon-image/issues/37
-    if (!width || ! height) {
+    if (!width || !height) {
       if (height) {
         this._storage.advanceCursor(height);
       }

addons/addon-image/src/SixelImageStorage.ts

@@ -4,7 +4,7 @@
  */
 
 import { ImageStorage, CELL_SIZE_DEFAULT } from './ImageStorage';
-import { IImageAddonOptions, ITerminalExt } from './Types';
+import { IImageAddonOptions, ITerminalExt, IAddImageOpts } from './Types';
 import { ImageRenderer } from './ImageRenderer';
 
 /**
@@ -15,6 +15,7 @@ import { ImageRenderer } from './ImageRenderer';
  * - advanceCursor for empty sixels carrying only height
  */
 export class SixelImageStorage {
+  private _addImageOpts: IAddImageOpts = { scrolling: true, layer: 'top', zIndex: 0, cursorPos: 'vt340' };
   constructor(
     private readonly _storage: ImageStorage,
     private readonly _opts: IImageAddonOptions,
@@ -27,7 +28,8 @@ export class SixelImageStorage {
    * Cursor behavior depends on the sixelScrolling option (DECSET 80).
    */
   public addImage(img: HTMLCanvasElement | ImageBitmap): void {
-    this._storage.addImage(img, this._opts.sixelScrolling);
+    this._addImageOpts.scrolling = this._opts.sixelScrolling;
+    this._storage.addImage(img, this._addImageOpts);
   }
 
   /**

addons/addon-image/src/Types.ts

@@ -100,6 +100,14 @@ export interface ICellSize {
 }
 
 export type ImageLayer = 'top' | 'bottom';
+export type CursorPos = 'vt340' | 'iip';
+
+export interface IAddImageOpts {
+  scrolling: boolean;
+  layer: ImageLayer;
+  zIndex: number;
+  cursorPos: CursorPos;
+}
 
 export interface IImageSpec {
   orig: HTMLCanvasElement | ImageBitmap | undefined;

addons/addon-image/src/kitty/KittyImageStorage.ts

@@ -5,7 +5,7 @@
 
 import { IDisposable } from '@xterm/xterm';
 import { ImageStorage } from '../ImageStorage';
-import { ImageLayer } from '../Types';
+import { ImageLayer, IAddImageOpts } from '../Types';
 import { IKittyImageData } from './KittyGraphicsTypes';
 
 // Kitty-specific image storage controller.
@@ -42,6 +42,7 @@ export class KittyImageStorage implements IDisposable {
       this._images.delete(kittyId);
     }
   };
+  private _addImageOpts: IAddImageOpts = { scrolling: true, layer: 'top', zIndex: 0, cursorPos: 'iip' };
 
   constructor(
     private readonly _storage: ImageStorage
@@ -98,7 +99,10 @@ export class KittyImageStorage implements IDisposable {
     if (oldStorageId !== undefined) {
       this._storageIdToKittyId.delete(oldStorageId);
     }
-    const storageId = this._storage.addImage(image, scrolling, layer, zIndex);
+    this._addImageOpts.scrolling = scrolling;
+    this._addImageOpts.layer = layer;
+    this._addImageOpts.zIndex = zIndex;
+    const storageId = this._storage.addImage(image, this._addImageOpts);
     this._kittyIdToStorageId.set(kittyId, storageId);
     this._storageIdToKittyId.set(storageId, kittyId);
   }

addons/addon-image/test/ImageAddon.test.ts

@@ -290,6 +290,67 @@ test.describe('ImageAddon', () => {
     });
   });
 
+  test.describe('IIP support', () => {
+    test('size params is optional/informative', async () => {
+      // too small size param
+      await ctx.proxy.write(`\x1b]1337;File=inline=1;size=5:${PALETTE_PNG_BASE64}\x07`);
+      deepStrictEqual(await getOrigSize(1), [640, 80]);
+      // no size aparm at all
+      await ctx.proxy.write(`\x1b[10H\x1b]1337;File=inline=1:${PALETTE_QOI_BASE64}\x07`);
+      deepStrictEqual(await getOrigSize(2), [640, 80]);
+    });
+    test.skip('FilePart support - bytewise', async () => {
+      // opener
+      await ctx.proxy.write(`\x1b]1337;MultipartFile=inline=1\x07`);
+      // byte-wise
+      for (let i = 0; i < PALETTE_PNG_BASE64.length; ++i) {
+        await ctx.proxy.write(`\x1b]1337;FilePart=${PALETTE_PNG_BASE64[i]}\x07`);
+      }
+      // finalizer
+      await ctx.proxy.write(`\x1b]1337;FileEnd\x07`);
+      deepStrictEqual(await getOrigSize(1), [640, 80]);
+    });
+    test('FilePart support - chunks', async () => {
+      // opener
+      await ctx.proxy.write(`\x1b]1337;MultipartFile=inline=1\x07`);
+      // chunks
+      for (let i = 0; i < PALETTE_PNG_BASE64.length; i += 256) {
+        await ctx.proxy.write(`\x1b]1337;FilePart=${PALETTE_PNG_BASE64.slice(i, i + 256)}\x07`);
+      }
+      // finalizer
+      await ctx.proxy.write(`\x1b]1337;FileEnd\x07`);
+      deepStrictEqual(await getOrigSize(1), [640, 80]);
+    });
+    test('FilePart support - edgecases', async () => {
+      // multiple opener do not harm
+      for (let i = 0; i < 10; ++i) {
+        await ctx.proxy.write(`\x1b]1337;MultipartFile=inline=1\x07`);
+      }
+      // multiple finalizer do not harm
+      for (let i = 0; i < 5; ++i) {
+        await ctx.proxy.write(`\x1b]1337;FileEnd\x07`);
+      }
+      // chunks w'o opener are ignored
+      for (let i = 0; i < PALETTE_PNG_BASE64.length; i += 256) {
+        await ctx.proxy.write(`\x1b]1337;FilePart=${PALETTE_PNG_BASE64.slice(i, i + 256)}\x07`);
+      }
+      await ctx.proxy.write(`\x1b]1337;FileEnd\x07`);
+      pollFor(ctx.page, 'window.imageAddon._storage._images.size', 0);
+    });
+    test('FilePart support - other IIP sequence cancels chunked image', async () => {
+      // opener
+      await ctx.proxy.write(`\x1b]1337;MultipartFile=inline=1\x07`);
+      // chunks
+      for (let i = 0; i < PALETTE_PNG_BASE64.length; i += 256) {
+        await ctx.proxy.write(`\x1b]1337;FilePart=${PALETTE_PNG_BASE64.slice(i, i + 256)}\x07`);
+      }
+      // finalizer skipped
+      // write spinfox.png
+      await ctx.proxy.write(TESTDATA_IIP[1][0]);
+      deepStrictEqual(await getOrigSize(1), TESTDATA_IIP[1][1]);
+    });
+  });
+
   test.describe('IIP support - testimages', () => {
     test('palette.png', async () => {
       await ctx.proxy.write(TESTDATA_IIP[0][0]);

addons/addon-image/test/KittyGraphics.test.ts

@@ -539,7 +539,6 @@ test.describe('Kitty Graphics Protocol', () => {
 
   test.describe('Query support (a=q)', () => {
     test('responds with OK for capability query without payload', async () => {
-      let response = '';
       await ctx.page.evaluate(() => {
         (window as any).kittyResponse = '';
         (window as any).term.onData((data: string) => { (window as any).kittyResponse = data; });
@@ -548,12 +547,11 @@ test.describe('Kitty Graphics Protocol', () => {
       await ctx.proxy.write('\x1b_Gi=31,a=q;\x1b\\');
       await timeout(100);
 
-      response = await ctx.page.evaluate('window.kittyResponse');
+      const response = await ctx.page.evaluate('window.kittyResponse');
       strictEqual(response, '\x1b_Gi=31;OK\x1b\\');
     });
 
     test('responds with OK for valid PNG query', async () => {
-      let response = '';
       await ctx.page.evaluate(() => {
         (window as any).kittyResponse = '';
         (window as any).term.onData((data: string) => { (window as any).kittyResponse = data; });
@@ -562,7 +560,7 @@ test.describe('Kitty Graphics Protocol', () => {
       await ctx.proxy.write(`\x1b_Gi=42,a=q,f=100;${KITTY_BLACK_1X1_BASE64}\x1b\\`);
       await timeout(100);
 
-      response = await ctx.page.evaluate('window.kittyResponse');
+      const response = await ctx.page.evaluate('window.kittyResponse');
       strictEqual(response, '\x1b_Gi=42;OK\x1b\\');
     });
 
@@ -578,7 +576,6 @@ test.describe('Kitty Graphics Protocol', () => {
     });
 
     test('responds with error for invalid base64', async () => {
-      let response = '';
       await ctx.page.evaluate(() => {
         (window as any).kittyResponse = '';
         (window as any).term.onData((data: string) => { (window as any).kittyResponse = data; });
@@ -587,12 +584,11 @@ test.describe('Kitty Graphics Protocol', () => {
       await ctx.proxy.write('\x1b_Gi=60,a=q,f=100;!!!invalid!!!\x1b\\');
       await timeout(100);
 
-      response = await ctx.page.evaluate('window.kittyResponse');
+      const response: string = await ctx.page.evaluate('window.kittyResponse');
       strictEqual(response.startsWith('\x1b_Gi=60;EINVAL:'), true);
     });
 
     test('responds with error for RGB data without dimensions', async () => {
-      let response = '';
       await ctx.page.evaluate(() => {
         (window as any).kittyResponse = '';
         (window as any).term.onData((data: string) => { (window as any).kittyResponse = data; });
@@ -601,7 +597,7 @@ test.describe('Kitty Graphics Protocol', () => {
       await ctx.proxy.write('\x1b_Gi=70,a=q,f=24;AAAA\x1b\\');
       await timeout(100);
 
-      response = await ctx.page.evaluate('window.kittyResponse');
+      const response = await ctx.page.evaluate('window.kittyResponse');
       strictEqual(response, '\x1b_Gi=70;EINVAL:width and height required for raw pixel data\x1b\\');
     });
 
@@ -642,7 +638,6 @@ test.describe('Kitty Graphics Protocol', () => {
     });
 
     test('responds with EINVAL when both i and I keys are specified', async () => {
-      let response = '';
       await ctx.page.evaluate(() => {
         (window as any).kittyResponse = '';
         (window as any).term.onData((data: string) => { (window as any).kittyResponse = data; });
@@ -652,12 +647,11 @@ test.describe('Kitty Graphics Protocol', () => {
       await ctx.proxy.write(`\x1b_Gi=100,I=200,a=q,f=100;${KITTY_BLACK_1X1_BASE64}\x1b\\`);
       await timeout(100);
 
-      response = await ctx.page.evaluate('window.kittyResponse');
+      const response = await ctx.page.evaluate('window.kittyResponse');
       strictEqual(response, '\x1b_Gi=100;EINVAL:cannot specify both i and I keys\x1b\\');
     });
 
     test('responds with EINVAL for i+I conflict even without payload', async () => {
-      let response = '';
       await ctx.page.evaluate(() => {
         (window as any).kittyResponse = '';
         (window as any).term.onData((data: string) => { (window as any).kittyResponse = data; });
@@ -667,7 +661,7 @@ test.describe('Kitty Graphics Protocol', () => {
       await ctx.proxy.write('\x1b_Gi=101,I=201,a=d\x1b\\');
       await timeout(100);
 
-      response = await ctx.page.evaluate('window.kittyResponse');
+      const response = await ctx.page.evaluate('window.kittyResponse');
       strictEqual(response, '\x1b_Gi=101;EINVAL:cannot specify both i and I keys\x1b\\');
     });
   });

addons/addon-ligatures/package.json

@@ -31,15 +31,11 @@
   ],
   "license": "MIT",
   "dependencies": {
-    "lru-cache": "^6.0.0",
-    "opentype.js": "^0.8.0"
+    "lru-cache": "^11.3.6",
+    "opentype.js": "^2.0.0"
   },
   "devDependencies": {
-    "@types/lru-cache": "^5.1.0",
-    "@types/opentype.js": "^0.7.0",
-    "axios": "^1.15.2",
-    "font-finder": "^1.1.0",
-    "mkdirp": "0.5.5",
-    "yauzl": "^3.2.1"
+    "@types/opentype.js": "^1.3.9",
+    "font-finder": "^1.1.0"
   }
 }

addons/addon-ligatures/src/fontLigatures/index.ts

@@ -1,5 +1,5 @@
 import * as opentype from 'opentype.js';
-import LRUCache = require('lru-cache');
+import { LRUCache } from 'lru-cache';
 
 import { IFont, ILigatureData, IFlattenedLookupTree, ILookupTree, IOptions } from './types';
 import mergeTrees from './merge';
@@ -23,8 +23,8 @@ class FontImpl implements IFont {
 
     if (options.cacheSize > 0) {
       this._cache = new LRUCache({
-        max: options.cacheSize,
-        length: ((val: ILigatureData | [number, number][], key: string) => key.length) as any
+        maxSize: options.cacheSize,
+        sizeCalculation: ((val: ILigatureData | [number, number][], key: string) => key.length) as any
       });
     }
 

addons/addon-ligatures/src/fontLigatures/mergeRange.ts

@@ -44,7 +44,6 @@ export default function mergeRange(ranges: [number, number][], newRangeStart: nu
         // current range
         ranges[i - 1][1] = Math.max(newRangeEnd, range[1]);
         ranges.splice(i, 1);
-        inRange = false;
         return ranges;
       }
       // Case 7: New range extends from previous range past the

addons/addon-progress/test/ProgressAddon.test.ts

@@ -9,15 +9,18 @@ import { ITestContext, createTestContext, openTerminal } from '../../../test/pla
 
 
 let ctx: ITestContext;
-test.beforeAll(async ({ browser }) => {
-  ctx = await createTestContext(browser);
-  ctx.page.setViewportSize({ width: 1024, height: 768 });
-  await openTerminal(ctx);
-});
-test.afterAll(async () => await ctx.page.close());
-
 
 test.describe('ProgressAddon', () => {
+  test.describe.configure({ mode: 'serial' });
+
+  test.beforeAll(async ({ browser }) => {
+    ctx = await createTestContext(browser);
+    await openTerminal(ctx);
+  });
+  test.afterAll(async () => {
+    await ctx?.page?.close();
+  });
+
   test.beforeEach(async function(): Promise<any> {
     await ctx.page.evaluate(`
       window.progressStack = [];

addons/addon-search/src/SearchEngine.ts

@@ -174,7 +174,7 @@ export class SearchEngine {
     this._terminal.clearSelection();
 
     let startRow = this._terminal.buffer.active.baseY + this._terminal.rows - 1;
-    let startCol = this._terminal.cols;
+    const startCol = this._terminal.cols;
     const isReverseSearch = true;
 
     this._lineCache.initLinesCache();
@@ -186,14 +186,14 @@ export class SearchEngine {
     let result: ISearchResult | undefined;
     if (prevSelectedPos) {
       searchPosition.startRow = startRow = prevSelectedPos.start.y;
-      searchPosition.startCol = startCol = prevSelectedPos.start.x;
+      searchPosition.startCol = prevSelectedPos.start.x;
       if (cachedSearchTerm !== term) {
         // Try to expand selection to right first.
         result = this._findInLine(term, searchPosition, searchOptions, false);
         if (!result) {
           // If selection was not able to be expanded to the right, then try reverse search
           searchPosition.startRow = startRow = prevSelectedPos.end.y;
-          searchPosition.startCol = startCol = prevSelectedPos.end.x;
+          searchPosition.startCol = prevSelectedPos.end.x;
         }
       }
     }

addons/addon-serialize/benchmark/tsconfig.json

@@ -7,10 +7,10 @@
     "rootDir": "..",
     "outDir": "../out-benchmark",
     "types": ["../../../node_modules/@types/node"],
-    "moduleResolution": "node",
+    "moduleResolution": "nodenext",
     "strict": false,
     "target": "es2021",
-    "module": "commonjs",
+    "module": "nodenext",
     "paths": {
       "common/*": ["../../../src/common/*"],
       "browser/*": ["../../../src/browser/*"],

addons/addon-unicode-graphemes/benchmark/tsconfig.json

@@ -4,10 +4,10 @@
     "rootDir": "..",
     "outDir": "../out-benchmark",
     "types": ["../../../node_modules/@types/node"],
-    "moduleResolution": "node",
+    "moduleResolution": "nodenext",
     "strict": false,
     "target": "es2015",
-    "module": "commonjs",
+    "module": "nodenext",
     "paths": {
       "common/*": ["../../../src/common/*"],
       "browser/*": ["../../../src/browser/*"],

addons/addon-web-fonts/test/WebFontsAddon.test.ts

@@ -78,7 +78,22 @@ test.describe('WebFontsAddon', () => {
       const data = await ctx.page.evaluate(`
           document.styleSheets[0].insertRule("@font-face {font-family: Kongtext; src: url(/fonts/kongtext.regular.ttf) format('truetype'); unicode-range: U+00A0-00FF}", 0);
         `);
-      deepStrictEqual(await getDocumentFonts(), [{ family: 'Kongtext', status: 'unloaded' }]);
+      let fonts = await getDocumentFonts();
+      // safari may have loaded the font, firefox & chrome never load it
+      if (browser.browserType().name() === 'webkit') {
+        try {
+          deepStrictEqual(fonts, [{ family: 'Kongtext', status: 'loading' }]);
+        } catch (e) {
+          try {
+            deepStrictEqual(fonts, [{ family: 'Kongtext', status: 'loaded' }]);
+          } catch (e) {
+            deepStrictEqual(fonts, [{ family: 'Kongtext', status: 'unloaded' }]);
+          }
+        }
+      } else {
+        deepStrictEqual(fonts, [{ family: 'Kongtext', status: 'unloaded' }]);
+      }
+
 
       // broken case: webfont in ctor without addon usage
       await ctx.page.evaluate(`
@@ -86,15 +101,20 @@ test.describe('WebFontsAddon', () => {
           window.helperTerm.open(term.element);
         `);
 
-      // safari loads the font, firefox & chrome dont
+      fonts = await getDocumentFonts();
+      // safari might load the font, firefox & chrome dont
       if (browser.browserType().name() === 'webkit') {
         try {
-          deepStrictEqual(await getDocumentFonts(), [{ family: 'Kongtext', status: 'loading' }]);
+          deepStrictEqual(fonts, [{ family: 'Kongtext', status: 'loading' }]);
         } catch (e) {
-          deepStrictEqual(await getDocumentFonts(), [{ family: 'Kongtext', status: 'loaded' }]);
+          try {
+            deepStrictEqual(fonts, [{ family: 'Kongtext', status: 'loaded' }]);
+          } catch (e) {
+            deepStrictEqual(fonts, [{ family: 'Kongtext', status: 'unloaded' }]);
+          }
         }
       } else {
-        deepStrictEqual(await getDocumentFonts(), [{ family: 'Kongtext', status: 'unloaded' }]);
+        deepStrictEqual(fonts, [{ family: 'Kongtext', status: 'unloaded' }]);
       }
 
       // good case: addon fixes layout for webfont in ctor

addons/addon-web-fonts/test/tsconfig.json

@@ -5,7 +5,6 @@
     "lib": [
       "es2021",
     ],
-    // "downlevelIteration": true,
     "rootDir": ".",
     "outDir": "../out-test",
     "sourceMap": true,

addons/addon-web-links/src/WebLinkProvider.ts

@@ -113,8 +113,8 @@ export class LinkComputer {
     let line: IBufferLine | undefined;
     let topIdx = lineIndex;
     let bottomIdx = lineIndex;
-    let length = 0;
-    let content = '';
+    let length;
+    let content;
     const lines: string[] = [];
 
     if ((line = terminal.buffer.active.getLine(lineIndex))) {

addons/addon-web-links/test/tsconfig.json

@@ -5,7 +5,6 @@
     "lib": [
       "es2021",
     ],
-    // "downlevelIteration": true,
     "rootDir": ".",
     "outDir": "../out-test",
     "sourceMap": true,

addons/addon-webgl/src/CharAtlasUtils.test.ts

@@ -0,0 +1,87 @@
+/**
+ * Copyright (c) 2026 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import { assert } from 'chai';
+import { configEquals } from './CharAtlasUtils';
+import { ICharAtlasConfig } from './Types';
+import { NULL_COLOR } from 'common/Color';
+import { IColor } from 'common/Types';
+
+function createTestConfig(overrides: Partial<ICharAtlasConfig> = {}): ICharAtlasConfig {
+  const color: IColor = { css: '#ffffff', rgba: 0xffffffff };
+  const contrastCache = {
+    clear: () => {},
+    setCss: () => {},
+    getCss: () => undefined,
+    setColor: () => {},
+    getColor: () => undefined
+  };
+  const colors = {
+    foreground: color,
+    background: color,
+    cursor: NULL_COLOR,
+    cursorAccent: NULL_COLOR,
+    selectionForeground: undefined,
+    selectionBackgroundTransparent: NULL_COLOR,
+    selectionBackgroundOpaque: NULL_COLOR,
+    selectionInactiveBackgroundTransparent: NULL_COLOR,
+    selectionInactiveBackgroundOpaque: NULL_COLOR,
+    overviewRulerBorder: NULL_COLOR,
+    scrollbarSliderBackground: NULL_COLOR,
+    scrollbarSliderHoverBackground: NULL_COLOR,
+    scrollbarSliderActiveBackground: NULL_COLOR,
+    ansi: new Array(256).fill(color),
+    contrastCache,
+    halfContrastCache: contrastCache
+  };
+  return {
+    customGlyphs: true,
+    devicePixelRatio: 1,
+    deviceMaxTextureSize: 4096,
+    letterSpacing: 0,
+    lineHeight: 1,
+    fontSize: 15,
+    fontFamily: 'monospace',
+    fontWeight: 'normal',
+    fontWeightBold: 'bold',
+    deviceCellWidth: 10,
+    deviceCellHeight: 20,
+    deviceCharWidth: 8,
+    deviceCharHeight: 16,
+    allowTransparency: false,
+    drawBoldTextInBrightColors: true,
+    minimumContrastRatio: 1,
+    colors,
+    ...overrides
+  };
+}
+
+describe('CharAtlasUtils', () => {
+  describe('configEquals', () => {
+    it('should return true for identical configs', () => {
+      const a = createTestConfig();
+      const b = createTestConfig();
+      assert.ok(configEquals(a, b));
+    });
+
+    it('should return false when deviceMaxTextureSize differs', () => {
+      const a = createTestConfig();
+      const b = createTestConfig({ deviceMaxTextureSize: 8192 });
+      assert.ok(!configEquals(a, b));
+    });
+
+    it('should return false when deviceCellWidth differs', () => {
+      const a = createTestConfig();
+      const b = createTestConfig({ deviceCellWidth: 11 });
+      assert.ok(!configEquals(a, b));
+    });
+
+    it('should return false when deviceCellHeight differs', () => {
+      const a = createTestConfig();
+      const b = createTestConfig({ deviceCellHeight: 21 });
+      assert.ok(!configEquals(a, b));
+    });
+  });
+});

addons/addon-webgl/src/CharAtlasUtils.ts

@@ -59,6 +59,7 @@ export function configEquals(a: ICharAtlasConfig, b: ICharAtlasConfig): boolean
     }
   }
   return a.devicePixelRatio === b.devicePixelRatio &&
+      a.deviceMaxTextureSize === b.deviceMaxTextureSize &&
       a.customGlyphs === b.customGlyphs &&
       a.lineHeight === b.lineHeight &&
       a.letterSpacing === b.letterSpacing &&
@@ -67,6 +68,8 @@ export function configEquals(a: ICharAtlasConfig, b: ICharAtlasConfig): boolean
       a.fontWeight === b.fontWeight &&
       a.fontWeightBold === b.fontWeightBold &&
       a.allowTransparency === b.allowTransparency &&
+      a.deviceCellWidth === b.deviceCellWidth &&
+      a.deviceCellHeight === b.deviceCellHeight &&
       a.deviceCharWidth === b.deviceCharWidth &&
       a.deviceCharHeight === b.deviceCharHeight &&
       a.drawBoldTextInBrightColors === b.drawBoldTextInBrightColors &&

addons/addon-webgl/src/GlyphRenderer.ts

@@ -9,7 +9,7 @@ import { Disposable, toDisposable } from 'common/Lifecycle';
 import { Terminal } from '@xterm/xterm';
 import { IRenderModel, IWebGL2RenderingContext, IWebGLVertexArrayObject, type IRasterizedGlyph, type ITextureAtlas } from './Types';
 import { createProgram, GLTexture, PROJECTION_MATRIX } from './WebglUtils';
-import type { IOptionsService } from 'common/services/Services';
+import type { ILogService, IOptionsService } from 'common/services/Services';
 import { allowRescaling, throwIfFalsy } from 'browser/renderer/shared/RendererUtils';
 
 interface IVertices {
@@ -114,7 +114,8 @@ export class GlyphRenderer extends Disposable {
     private readonly _terminal: Terminal,
     private readonly _gl: IWebGL2RenderingContext,
     private _dimensions: IRenderDimensions,
-    private readonly _optionsService: IOptionsService
+    private readonly _optionsService: IOptionsService,
+    private readonly _logService: ILogService
   ) {
     super();
 
@@ -127,7 +128,7 @@ export class GlyphRenderer extends Disposable {
       TextureAtlas.maxTextureSize = throwIfFalsy(gl.getParameter(gl.MAX_TEXTURE_SIZE) as number | null);
     }
 
-    this._program = throwIfFalsy(createProgram(gl, vertexShaderSource, createFragmentShaderSource(TextureAtlas.maxAtlasPages)));
+    this._program = throwIfFalsy(createProgram(gl, vertexShaderSource, createFragmentShaderSource(TextureAtlas.maxAtlasPages), this._logService));
     this._register(toDisposable(() => gl.deleteProgram(this._program)));
 
     // Uniform locations
@@ -136,8 +137,9 @@ export class GlyphRenderer extends Disposable {
     this._textureLocation = throwIfFalsy(gl.getUniformLocation(this._program, 'u_texture'));
 
     // Create and set the vertex array object
-    this._vertexArrayObject = gl.createVertexArray();
-    gl.bindVertexArray(this._vertexArrayObject);
+    const vertexArrayObject = this._vertexArrayObject = gl.createVertexArray();
+    this._register(toDisposable(() => gl.deleteVertexArray(vertexArrayObject)));
+    gl.bindVertexArray(vertexArrayObject);
 
     // Setup a_unitquad, this defines the 4 vertices of a rectangle
     const unitQuadVertices = new Float32Array([0, 0, 1, 0, 0, 1, 1, 1]);

addons/addon-webgl/src/RectangleRenderer.ts

@@ -14,6 +14,7 @@ import { RenderModelConstants } from './RenderModel';
 import { IRenderModel, IWebGL2RenderingContext, IWebGLVertexArrayObject } from './Types';
 import { createProgram, expandFloat32Array, PROJECTION_MATRIX } from './WebglUtils';
 import { throwIfFalsy } from 'browser/renderer/shared/RendererUtils';
+import type { ILogService } from 'common/services/Services';
 
 const enum VertexAttribLocations {
   POSITION = 0,
@@ -89,21 +90,23 @@ export class RectangleRenderer extends Disposable {
     private _terminal: Terminal,
     private _gl: IWebGL2RenderingContext,
     private _dimensions: IRenderDimensions,
-    private readonly _themeService: IThemeService
+    private readonly _themeService: IThemeService,
+    private readonly _logService: ILogService
   ) {
     super();
 
     const gl = this._gl;
 
-    this._program = throwIfFalsy(createProgram(gl, vertexShaderSource, fragmentShaderSource));
+    this._program = throwIfFalsy(createProgram(gl, vertexShaderSource, fragmentShaderSource, this._logService));
     this._register(toDisposable(() => gl.deleteProgram(this._program)));
 
     // Uniform locations
     this._projectionLocation = throwIfFalsy(gl.getUniformLocation(this._program, 'u_projection'));
 
     // Create and set the vertex array object
-    this._vertexArrayObject = gl.createVertexArray();
-    gl.bindVertexArray(this._vertexArrayObject);
+    const vertexArrayObject = this._vertexArrayObject = gl.createVertexArray();
+    this._register(toDisposable(() => gl.deleteVertexArray(vertexArrayObject)));
+    gl.bindVertexArray(vertexArrayObject);
 
     // Setup a_unitquad, this defines the 4 vertices of a rectangle
     const unitQuadVertices = new Float32Array([0, 0, 1, 0, 0, 1, 1, 1]);

addons/addon-webgl/src/TextureAtlas.ts

@@ -109,6 +109,7 @@ export class TextureAtlas implements ITextureAtlas {
       page.canvas.remove();
     }
     this._onAddTextureAtlasCanvas.dispose();
+    this._onRemoveTextureAtlasCanvas.dispose();
   }
 
   public warmUp(): void {
@@ -529,7 +530,7 @@ export class TextureAtlas implements ITextureAtlas {
     let customGlyph = false;
     if (this._config.customGlyphs !== false) {
       const variantOffset = this._workAttributeData.getUnderlineVariantOffset();
-      customGlyph = tryDrawCustomGlyph(this._tmpCtx, chars, padding, padding, this._config.deviceCellWidth, this._config.deviceCellHeight, this._config.deviceCharWidth, this._config.deviceCharHeight, this._config.fontSize, this._config.devicePixelRatio, backgroundColor.css, variantOffset);
+      customGlyph = tryDrawCustomGlyph(this._tmpCtx, chars, padding, padding, this._config.deviceCellWidth, this._config.deviceCellHeight, this._config.deviceCharWidth, this._config.deviceCharHeight, this._config.fontSize, this._config.devicePixelRatio, this._logService, backgroundColor.css, variantOffset);
     }
 
     // Whether to clear pixels based on a threshold difference between the glyph color and the

addons/addon-webgl/src/Types.ts

@@ -28,6 +28,7 @@ export interface ICursorRenderModel {
 export interface IWebGL2RenderingContext extends WebGLRenderingContext {
   vertexAttribDivisor(index: number, divisor: number): void;
   createVertexArray(): IWebGLVertexArrayObject;
+  deleteVertexArray(vao: IWebGLVertexArrayObject): void;
   bindVertexArray(vao: IWebGLVertexArrayObject): void;
   drawElementsInstanced(mode: number, count: number, type: number, offset: number, instanceCount: number): void;
 }

addons/addon-webgl/src/WebglAddon.ts

@@ -9,7 +9,7 @@ import { ICharacterJoinerService, ICharSizeService, ICoreBrowserService, IRender
 import { ITerminal } from 'browser/Types';
 import { Disposable, toDisposable } from 'common/Lifecycle';
 import { getSafariVersion, isSafari } from 'common/Platform';
-import { ICoreService, IDecorationService, IOptionsService } from 'common/services/Services';
+import { ICoreService, IDecorationService, ILogService, IOptionsService } from 'common/services/Services';
 import { IWebGL2RenderingContext } from './Types';
 import { WebglRenderer } from './WebglRenderer';
 import { Emitter, EventUtils } from 'common/Event';
@@ -65,6 +65,7 @@ export class WebglAddon extends Disposable implements ITerminalAddon, IWebglApi
     const charSizeService: ICharSizeService = unsafeCore._charSizeService;
     const coreBrowserService: ICoreBrowserService = unsafeCore._coreBrowserService;
     const decorationService: IDecorationService = unsafeCore._decorationService;
+    const logService: ILogService = unsafeCore._logService;
     const themeService: IThemeService = unsafeCore._themeService;
 
     this._renderer = this._register(new WebglRenderer(
@@ -74,6 +75,7 @@ export class WebglAddon extends Disposable implements ITerminalAddon, IWebglApi
       coreBrowserService,
       coreService,
       decorationService,
+      logService,
       optionsService,
       themeService,
       this._customGlyphs,

addons/addon-webgl/src/WebglRenderer.ts

@@ -15,7 +15,7 @@ import { AttributeData } from 'common/buffer/AttributeData';
 import { CellData } from 'common/buffer/CellData';
 import { Attributes, Content, FgFlags, NULL_CELL_CHAR, NULL_CELL_CODE } from 'common/buffer/Constants';
 import { TextBlinkStateManager } from 'browser/renderer/shared/TextBlinkStateManager';
-import { ICoreService, IDecorationService, IOptionsService } from 'common/services/Services';
+import { ICoreService, IDecorationService, ILogService, IOptionsService } from 'common/services/Services';
 import { Terminal } from '@xterm/xterm';
 import { GlyphRenderer } from './GlyphRenderer';
 import { RectangleRenderer } from './RectangleRenderer';
@@ -77,6 +77,7 @@ export class WebglRenderer extends Disposable implements IRenderer {
     private readonly _coreBrowserService: ICoreBrowserService,
     private readonly _coreService: ICoreService,
     private readonly _decorationService: IDecorationService,
+    private readonly _logService: ILogService,
     private readonly _optionsService: IOptionsService,
     private readonly _themeService: IThemeService,
     private readonly _customGlyphs: boolean = true,
@@ -122,19 +123,19 @@ export class WebglRenderer extends Disposable implements IRenderer {
     this._deviceMaxTextureSize = this._gl.getParameter(this._gl.MAX_TEXTURE_SIZE);
 
     this._register(addDisposableListener(this._canvas, 'webglcontextlost', (e) => {
-      console.log('webglcontextlost event received');
+      this._logService.debug('webglcontextlost event received');
       // Prevent the default behavior in order to enable WebGL context restoration.
       e.preventDefault();
       // Wait a few seconds to see if the 'webglcontextrestored' event is fired.
       // If not, dispatch the onContextLoss notification to observers.
       this._contextRestorationTimeout = setTimeout(() => {
         this._contextRestorationTimeout = undefined;
-        console.warn('webgl context not restored; firing onContextLoss');
+        this._logService.warn('webgl context not restored; firing onContextLoss');
         this._onContextLoss.fire(e);
       }, 3000 /* ms */);
     }));
     this._register(addDisposableListener(this._canvas, 'webglcontextrestored', (e) => {
-      console.warn('webglcontextrestored event received');
+      this._logService.warn('webglcontextrestored event received');
       clearTimeout(this._contextRestorationTimeout);
       this._contextRestorationTimeout = undefined;
       // The texture atlas and glyph renderer must be fully reinitialized
@@ -158,6 +159,8 @@ export class WebglRenderer extends Disposable implements IRenderer {
     this._isAttached = this._core.screenElement!.isConnected;
 
     this._register(toDisposable(() => {
+      clearTimeout(this._contextRestorationTimeout);
+      this._contextRestorationTimeout = undefined;
       for (const l of this._renderLayers) {
         l.dispose();
       }
@@ -274,8 +277,8 @@ export class WebglRenderer extends Disposable implements IRenderer {
    * Initializes members dependent on WebGL context state.
    */
   private _initializeWebGLState(): [RectangleRenderer, GlyphRenderer] {
-    this._rectangleRenderer.value = new RectangleRenderer(this._terminal, this._gl, this.dimensions, this._themeService);
-    this._glyphRenderer.value = new GlyphRenderer(this._terminal, this._gl, this.dimensions, this._optionsService);
+    this._rectangleRenderer.value = new RectangleRenderer(this._terminal, this._gl, this.dimensions, this._themeService, this._logService);
+    this._glyphRenderer.value = new GlyphRenderer(this._terminal, this._gl, this.dimensions, this._optionsService, this._logService);
 
     // Update dimensions and acquire char atlas
     this.handleCharSizeChanged();
@@ -424,8 +427,8 @@ export class WebglRenderer extends Disposable implements IRenderer {
     let line: IBufferLine;
     let joinedRanges: [number, number][];
     let isJoined: boolean;
-    let skipJoinedCheckUntilX: number = 0;
-    let isValidJoinRange: boolean = true;
+    let skipJoinedCheckUntilX: number;
+    let isValidJoinRange: boolean;
     let lastCharX: number;
     let range: [number, number];
     let isCursorRow: boolean;

addons/addon-webgl/src/WebglUtils.ts

@@ -4,6 +4,7 @@
  */
 
 import { throwIfFalsy } from 'browser/renderer/shared/RendererUtils';
+import type { ILogService } from 'common/services/Services';
 
 /**
  * A matrix that when multiplies will translate 0-1 coordinates (left to right,
@@ -16,21 +17,21 @@ export const PROJECTION_MATRIX = new Float32Array([
   -1, 1, 0, 1
 ]);
 
-export function createProgram(gl: WebGLRenderingContext, vertexSource: string, fragmentSource: string): WebGLProgram | undefined {
+export function createProgram(gl: WebGLRenderingContext, vertexSource: string, fragmentSource: string, logService: ILogService): WebGLProgram | undefined {
   const program = throwIfFalsy(gl.createProgram());
-  gl.attachShader(program, throwIfFalsy(createShader(gl, gl.VERTEX_SHADER, vertexSource)));
-  gl.attachShader(program, throwIfFalsy(createShader(gl, gl.FRAGMENT_SHADER, fragmentSource)));
+  gl.attachShader(program, throwIfFalsy(createShader(gl, gl.VERTEX_SHADER, vertexSource, logService)));
+  gl.attachShader(program, throwIfFalsy(createShader(gl, gl.FRAGMENT_SHADER, fragmentSource, logService)));
   gl.linkProgram(program);
   const success = gl.getProgramParameter(program, gl.LINK_STATUS);
   if (success) {
     return program;
   }
 
-  console.error(gl.getProgramInfoLog(program));
+  logService.error(gl.getProgramInfoLog(program));
   gl.deleteProgram(program);
 }
 
-export function createShader(gl: WebGLRenderingContext, type: number, source: string): WebGLShader | undefined {
+export function createShader(gl: WebGLRenderingContext, type: number, source: string, logService: ILogService): WebGLShader | undefined {
   const shader = throwIfFalsy(gl.createShader(type));
   gl.shaderSource(shader, source);
   gl.compileShader(shader);
@@ -39,7 +40,7 @@ export function createShader(gl: WebGLRenderingContext, type: number, source: st
     return shader;
   }
 
-  console.error(gl.getShaderInfoLog(shader));
+  logService.error(gl.getShaderInfoLog(shader));
   gl.deleteShader(shader);
 }
 

addons/addon-webgl/src/customGlyphs/CustomGlyphRasterizer.ts

@@ -4,6 +4,7 @@
  */
 
 import { throwIfFalsy } from 'browser/renderer/shared/RendererUtils';
+import type { ILogService } from 'common/services/Services';
 import { customGlyphDefinitions } from './CustomGlyphDefinitions';
 import { CustomGlyphDefinitionType, CustomGlyphScaleType, CustomGlyphVectorType, type CustomGlyphDefinitionPart, type CustomGlyphPathDrawFunctionDefinition, type CustomGlyphPatternDefinition, type ICustomGlyphSolidOctantBlockVector, type ICustomGlyphVectorShape } from './Types';
 
@@ -22,6 +23,7 @@ export function tryDrawCustomGlyph(
   deviceCharHeight: number,
   fontSize: number,
   devicePixelRatio: number,
+  logService: ILogService,
   backgroundColor?: string,
   variantOffset: number = 0
 ): boolean {
@@ -30,7 +32,7 @@ export function tryDrawCustomGlyph(
     // Normalize to array for uniform handling
     const parts = Array.isArray(unifiedCharDefinition) ? unifiedCharDefinition : [unifiedCharDefinition];
     for (const part of parts) {
-      drawDefinitionPart(ctx, part, xOffset, yOffset, deviceCellWidth, deviceCellHeight, deviceCharWidth, deviceCharHeight, fontSize, devicePixelRatio, backgroundColor, variantOffset);
+      drawDefinitionPart(ctx, part, xOffset, yOffset, deviceCellWidth, deviceCellHeight, deviceCharWidth, deviceCharHeight, fontSize, devicePixelRatio, logService, backgroundColor, variantOffset);
     }
     return true;
   }
@@ -49,6 +51,7 @@ function drawDefinitionPart(
   deviceCharHeight: number,
   fontSize: number,
   devicePixelRatio: number,
+  logService: ILogService,
   backgroundColor?: string,
   variantOffset: number = 0
 ): void {
@@ -79,7 +82,7 @@ function drawDefinitionPart(
       drawPatternChar(ctx, part.data, drawXOffset, drawYOffset, drawWidth, drawHeight, variantOffset);
       break;
     case CustomGlyphDefinitionType.PATH_FUNCTION:
-      drawPathFunctionCharacter(ctx, part.data, drawXOffset, drawYOffset, drawWidth, drawHeight, devicePixelRatio, part.strokeWidth);
+      drawPathFunctionCharacter(ctx, part.data, drawXOffset, drawYOffset, drawWidth, drawHeight, devicePixelRatio, logService, part.strokeWidth);
       break;
     case CustomGlyphDefinitionType.PATH:
       drawPathDefinitionCharacter(ctx, part.data, drawXOffset, drawYOffset, drawWidth, drawHeight, devicePixelRatio, part.strokeWidth);
@@ -88,7 +91,7 @@ function drawDefinitionPart(
       drawPathNegativeDefinitionCharacter(ctx, part.data, drawXOffset, drawYOffset, drawWidth, drawHeight, devicePixelRatio, backgroundColor);
       break;
     case CustomGlyphDefinitionType.VECTOR_SHAPE:
-      drawVectorShape(ctx, part.data, drawXOffset, drawYOffset, drawWidth, drawHeight, fontSize, devicePixelRatio);
+      drawVectorShape(ctx, part.data, drawXOffset, drawYOffset, drawWidth, drawHeight, fontSize, devicePixelRatio, logService);
       break;
     case CustomGlyphDefinitionType.BRAILLE:
       drawBrailleCharacter(ctx, part.data, drawXOffset, drawYOffset, drawWidth, drawHeight);
@@ -510,6 +513,7 @@ function drawPathFunctionCharacter(
   deviceCellWidth: number,
   deviceCellHeight: number,
   devicePixelRatio: number,
+  logService: ILogService,
   strokeWidth?: number
 ): void {
   ctx.save();
@@ -536,7 +540,7 @@ function drawPathFunctionCharacter(
     }
     const f = svgToCanvasInstructionMap[type];
     if (!f) {
-      console.error(`Could not find drawing instructions for "${type}"`);
+      logService.error(`Could not find drawing instructions for "${type}"`);
       continue;
     }
     const args: string[] = instruction.substring(1).split(',');
@@ -598,7 +602,8 @@ function drawVectorShape(
   deviceCellWidth: number,
   deviceCellHeight: number,
   fontSize: number,
-  devicePixelRatio: number
+  devicePixelRatio: number,
+  logService: ILogService
 ): void {
   // Clip the cell to make sure drawing doesn't occur beyond bounds
   const clipRegion = new Path2D();
@@ -619,7 +624,7 @@ function drawVectorShape(
     }
     const f = svgToCanvasInstructionMap[type];
     if (!f) {
-      console.error(`Could not find drawing instructions for "${type}"`);
+      logService.error(`Could not find drawing instructions for "${type}"`);
       continue;
     }
     const args: string[] = instruction.substring(1).split(',');

addons/addon-webgl/src/tsconfig.json

@@ -25,7 +25,6 @@
       ]
     },
     "strict": true,
-    "downlevelIteration": true,
     "experimentalDecorators": true,
     "types": [
       "../../../node_modules/@types/mocha"

demo/client/components/window/addonImageWindow.ts

@@ -65,7 +65,8 @@ export class AddonImageWindow extends BaseWindow implements IControlWindow {
     const dtIip = document.createElement('dt');
     dtIip.textContent = 'IIP (iTerm)';
     dlIip.appendChild(dtIip);
-    this._addDdWithButton(dlIip, 'image-demo3', 'palette');
+    this._addDdWithButton(dlIip, 'image-demo3', 'palette (png File)');
+    this._addDdWithButton(dlIip, 'image-demo4', 'dice (qoi MultipartFile)');
     container.appendChild(dlIip);
 
     // Kitty demos
@@ -141,6 +142,21 @@ export class AddonImageWindow extends BaseWindow implements IControlWindow {
         this._terminal.write(`\x1b]1337;File=inline=1;size=${data.length}:${btoa(sdata)}\x1b\\`);
       });
 
+    const iipDemoMulti = (url: string) => () => fetch(url)
+      .then(resp => resp.arrayBuffer())
+      .then(buffer => {
+        const data = new Uint8Array(buffer);
+        let sdata = '';
+        for (let i = 0; i < data.length; ++i) sdata += String.fromCharCode(data[i]);
+        const encoded = btoa(sdata);
+        this._terminal.write('\r\n');
+        this._terminal.write(`\x1b]1337;MultipartFile=inline=1\x1b\\`);
+        for (let i = 0; i < encoded.length; i += 100) {
+          this._terminal.write(`\x1b]1337;FilePart=${encoded.slice(i, i + 100)}\x1b\\`);
+        }
+        this._terminal.write(`\x1b]1337;FileEnd\x1b\\`);
+      });
+
     const kittyDemo = (url: string) => () => fetch(url)
       .then(resp => resp.arrayBuffer())
       .then(buffer => {
@@ -158,6 +174,8 @@ export class AddonImageWindow extends BaseWindow implements IControlWindow {
       sixelDemo('https://raw.githubusercontent.com/jerch/node-sixel/master/testfiles/test2.sixel'));
     document.getElementById('image-demo3')!.addEventListener('click',
       iipDemo('https://raw.githubusercontent.com/jerch/node-sixel/master/palette.png'));
+    document.getElementById('image-demo4')!.addEventListener('click',
+      iipDemoMulti('https://raw.githubusercontent.com/jerch/xterm-wasm-parts/master/fixtures/qoi/dice.qoi'));
     document.getElementById('image-demo-kitty1')!.addEventListener('click',
       kittyDemo('https://raw.githubusercontent.com/jerch/node-sixel/master/palette.png'));
 
@@ -176,7 +194,7 @@ export class AddonImageWindow extends BaseWindow implements IControlWindow {
       //   }
       // }
 
-      const pos = (this._terminal as any)._core._mouseService!.getCoords(ev, (this._terminal as any)._core.screenElement!, this._terminal.cols, this._terminal.rows);
+      const pos = (this._terminal as any)._core._mouseCoordsService!.getCoords(ev, (this._terminal as any)._core.screenElement!, this._terminal.cols, this._terminal.rows);
       const x = pos[0] - 1;
       const y = pos[1] - 1;
       const canvas = ev.shiftKey

demo/client/tsconfig.json

@@ -2,6 +2,7 @@
   "compilerOptions": {
     "module": "commonjs",
     "target": "es2021",
+    "types": ["node"],
     "outDir": "../out-demo/client",
     "rootDir": ".",
     "sourceMap": true,

demo/server/server.ts

@@ -118,7 +118,7 @@ function startServer(): void {
   });
 
   appWs.ws('/terminals/:pid', function (ws, req) {
-    const term = terminals[parseInt(req.params.pid)];
+    const term = terminals[parseInt(Array.isArray(req.params.pid) ? req.params.pid[0] : req.params.pid)];
     console.log('Connected to terminal ' + term.pid);
     temporaryDisposable[term.pid].dispose();
     delete temporaryDisposable[term.pid];

eslint.config.mjs

@@ -37,12 +37,13 @@ export default tseslint.config(
       '@stylistic/comma-spacing': ['warn', { before: false, after: true }],
       '@stylistic/indent': ['warn', 2],
       '@stylistic/semi': ['warn', 'always'],
-      '@stylistic/quotes': ['warn', 'single', { allowTemplateLiterals: true }],
+      '@stylistic/quotes': ['warn', 'single', { allowTemplateLiterals: 'always' }],
       '@stylistic/member-delimiter-style': ['warn', {
         multiline: { delimiter: 'semi', requireLast: true },
         singleline: { delimiter: 'comma', requireLast: false }
       }],
       '@stylistic/type-annotation-spacing': 'warn',
+      '@stylistic/space-unary-ops': 'warn',
 
       '@typescript-eslint/array-type': ['warn', { default: 'array', readonly: 'generic' }],
       '@typescript-eslint/consistent-type-assertions': 'warn',
@@ -85,6 +86,7 @@ export default tseslint.config(
       'eqeqeq': ['warn', 'always'],
       'jsdoc/check-alignment': 'warn',
       'jsdoc/check-param-names': 'warn',
+      'jsdoc/multiline-blocks': 'warn',
       'jsdoc/no-multi-asterisks': 'warn',
       'keyword-spacing': 'warn',
       'max-len': ['warn', {

eslint.config.typings.mjs

@@ -17,7 +17,7 @@ export default tseslint.config(
     rules: {
       '@stylistic/indent': ['warn', 2],
       '@stylistic/semi': ['warn', 'always'],
-      '@stylistic/quotes': ['warn', 'single', { allowTemplateLiterals: true }],
+      '@stylistic/quotes': ['warn', 'single', { allowTemplateLiterals: 'always' }],
       '@stylistic/member-delimiter-style': ['warn', {
         multiline: { delimiter: 'semi', requireLast: true },
         singleline: { delimiter: 'comma', requireLast: false }

package.json

@@ -75,40 +75,41 @@
     "prepublishOnly": "npm run package"
   },
   "devDependencies": {
+    "@eslint/js": "^10.0.1",
     "@lunapaint/png-codec": "^0.2.0",
-    "@playwright/test": "^1.57.0",
-    "@stylistic/eslint-plugin": "^4.4.1",
-    "@types/chai": "^4.2.22",
-    "@types/express": "4",
+    "@playwright/test": "^1.59.1",
+    "@stylistic/eslint-plugin": "^5.10.0",
+    "@types/chai": "^5.2.3",
+    "@types/express": "^5.0.6",
     "@types/express-ws": "^3.0.1",
-    "@types/jsdom": "^27.0.0",
-    "@types/mocha": "^9.0.0",
+    "@types/jsdom": "^28.0.1",
+    "@types/mocha": "^10.0.10",
     "@types/node": "^22.19.3",
     "@types/webpack": "^5.28.0",
     "@types/ws": "^8.2.0",
-    "@typescript-eslint/eslint-plugin": "^8.50.1",
-    "@typescript-eslint/parser": "^8.50.1",
-    "@typescript/native-preview": "^7.0.0-dev.20260213.1",
-    "chai": "^4.3.4",
+    "@typescript-eslint/eslint-plugin": "^8.59.2",
+    "@typescript-eslint/parser": "^8.59.2",
+    "@typescript/native-preview": "^7.0.0-dev.20260509.2",
+    "chai": "^6.2.2",
     "concurrently": "^9.1.2",
-    "esbuild": "~0.25.2",
-    "eslint": "^9.39.2",
-    "eslint-plugin-jsdoc": "^50.8.0",
-    "express": "^4.19.2",
+    "esbuild": "^0.28.0",
+    "eslint": "^10.3.0",
+    "eslint-plugin-jsdoc": "^62.9.0",
+    "express": "^5.2.1",
     "express-ws": "^5.0.2",
-    "jsdom": "^27.3.0",
-    "mocha": "^10.1.0",
+    "jsdom": "^29.1.1",
+    "mocha": "^11.7.5",
     "mustache": "^4.2.0",
     "node-pty": "^1.2.0-beta.9",
-    "nyc": "^17.1.0",
-    "source-map-loader": "^3.0.0",
+    "nyc": "^18.0.0",
+    "source-map-loader": "^5.0.0",
     "source-map-support": "^0.5.20",
-    "ts-loader": "^9.3.1",
+    "ts-loader": "^9.5.7",
     "typescript": "^5.9.3",
-    "typescript-eslint": "^8.50.1",
-    "webpack": "^5.61.0",
-    "webpack-cli": "^4.9.1",
-    "ws": "^8.2.3",
-    "xterm-benchmark": "^0.3.1"
+    "typescript-eslint": "^8.59.2",
+    "webpack": "^5.106.2",
+    "webpack-cli": "^7.0.2",
+    "ws": "^8.20.0",
+    "xterm-benchmark": "^0.3.2"
   }
 }

src/browser/CoreBrowserTerminal.ts

@@ -37,7 +37,7 @@ import { CharacterJoinerService } from 'browser/services/CharacterJoinerService'
 import { CoreBrowserService } from 'browser/services/CoreBrowserService';
 import { LinkProviderService } from 'browser/services/LinkProviderService';
 import { MouseCoordsService } from 'browser/services/MouseCoordsService';
-import { MouseService } from 'browser/services/MouseService';
+import { MouseEventCssClasses, MouseService } from 'browser/services/MouseService';
 import { RenderService } from 'browser/services/RenderService';
 import { SelectionService } from 'browser/services/SelectionService';
 import { ICharSizeService, ICharacterJoinerService, ICoreBrowserService, IKeyboardService, ILinkProviderService, IMouseCoordsService, IMouseService, IRenderService, ISelectionService, IThemeService } from 'browser/services/Services';
@@ -212,7 +212,7 @@ export class CoreBrowserTerminal extends CoreTerminal implements ITerminal {
     if (!this._themeService) return;
     for (const req of event) {
       let acc: 'foreground' | 'background' | 'cursor' | 'ansi';
-      let ident = '';
+      let ident: string;
       switch (req.index) {
         case SpecialColorIndex.FOREGROUND: // OSC 10 | 110
           acc = 'foreground';
@@ -563,8 +563,9 @@ export class CoreBrowserTerminal extends CoreTerminal implements ITerminal {
 
     try {
       this._onWillOpen.fire(this.element);
+    } catch (e) {
+      this._logService.error('onWillOpen handler threw an exception', e);
     }
-    catch { /* fails to load addon for some reason */ }
     if (!this._renderService.hasRenderer()) {
       this._renderService.setRenderer(this._createRenderer());
     }
@@ -617,11 +618,12 @@ export class CoreBrowserTerminal extends CoreTerminal implements ITerminal {
     this._register(addDisposableListener(this.element, 'mousedown', (e: MouseEvent) => this._selectionService!.handleMouseDown(e)));
 
     // apply mouse event classes set by escape codes before terminal was attached
-    if (this.mouseStateService.areMouseEventsActive) {
+    if (this.mouseStateService.areMouseEventsActive && !this.options.mouseEventsRequireAlt) {
       this._selectionService.disable();
-      this.element.classList.add('enable-mouse-events');
+      this.element.classList.add(MouseEventCssClasses.ENABLE_MOUSE_EVENTS);
     } else {
       this._selectionService.enable();
+      this.element.classList.remove(MouseEventCssClasses.ENABLE_MOUSE_EVENTS);
     }
 
     if (this.options.screenReaderMode) {

src/browser/Linkifier.test.ts

@@ -43,6 +43,20 @@ describe('Linkifier2', () => {
     },
     activate: () => { }
   };
+  const multiLineLink: ILink = {
+    text: 'foo',
+    range: {
+      start: {
+        x: 2,
+        y: 1
+      },
+      end: {
+        x: 4,
+        y: 2
+      }
+    },
+    activate: () => { }
+  };
 
   beforeEach(() => {
     const dom = new jsdom.JSDOM();
@@ -86,4 +100,30 @@ describe('Linkifier2', () => {
     linkifier.linkLeave({ classList: { add: () => { } } } as any, link, {} as any);
   });
 
+  it('onShowLinkUnderline event range is correct for wrapped links', done => {
+    linkifier.onShowLinkUnderline(e => {
+      assert.equal(multiLineLink.range.start.x - 1, e.x1);
+      assert.equal(multiLineLink.range.start.y - 1, e.y1);
+      assert.equal(multiLineLink.range.end.x, e.x2);
+      assert.equal(multiLineLink.range.end.y - 1, e.y2);
+
+      done();
+    });
+
+    linkifier.linkHover({ classList: { add: () => { } } } as any, multiLineLink, {} as any);
+  });
+
+  it('onHideLinkUnderline event range is correct for wrapped links', done => {
+    linkifier.onHideLinkUnderline(e => {
+      assert.equal(multiLineLink.range.start.x - 1, e.x1);
+      assert.equal(multiLineLink.range.start.y - 1, e.y1);
+      assert.equal(multiLineLink.range.end.x, e.x2);
+      assert.equal(multiLineLink.range.end.y - 1, e.y2);
+
+      done();
+    });
+
+    linkifier.linkLeave({ classList: { add: () => { } } } as any, multiLineLink, {} as any);
+  });
+
 });

src/browser/OscLinkProvider.test.ts

@@ -0,0 +1,105 @@
+/**
+ * Copyright (c) 2026 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import { assert } from 'chai';
+import { OscLinkProvider } from 'browser/OscLinkProvider';
+import { ILink } from 'browser/Types';
+import { createCellData, MockBufferService, MockOptionsService } from 'common/TestUtils.test';
+import { IBufferService, IOscLinkService } from 'common/services/Services';
+import { IBufferLine, IOscLinkData } from 'common/Types';
+
+class TestOscLinkService implements IOscLinkService {
+  public serviceBrand: any;
+  public registerLink(_linkData: IOscLinkData): number { return 0; }
+  public addLineToLink(_linkId: number, _y: number): void { }
+  public getLinkData(linkId: number): IOscLinkData | undefined {
+    return { uri: `https://example.com/${linkId}` };
+  }
+}
+
+function setText(line: IBufferLine | undefined, x: number, text: string): void {
+  if (!line) {
+    throw new Error('Missing buffer line');
+  }
+  for (let i = 0; i < text.length; i++) {
+    line.setCell(x + i, createCellData(0, text[i], 1));
+  }
+}
+
+function setUrl(line: IBufferLine | undefined, x: number, text: string, linkId: number): void {
+  if (!line) {
+    throw new Error('Missing buffer line');
+  }
+  for (let i = 0; i < text.length; i++) {
+    const cell = createCellData(0, text[i], 1);
+    cell.extended.urlId = linkId;
+    cell.updateExtended();
+    line.setCell(x + i, cell);
+  }
+}
+
+function getLinks(provider: OscLinkProvider, y: number): Promise<ILink[]> {
+  return new Promise(resolve => provider.provideLinks(y, links => resolve(links ?? [])));
+}
+
+describe('OscLinkProvider', () => {
+  let bufferService: IBufferService;
+  let provider: OscLinkProvider;
+
+  beforeEach(() => {
+    const optionsService = new MockOptionsService();
+    bufferService = new MockBufferService(5, 5, optionsService);
+    provider = new OscLinkProvider(bufferService, optionsService, new TestOscLinkService());
+  });
+
+  it('expands a wrapped link range backward to the previous line', async () => {
+    const line1 = bufferService.buffer.lines.get(0);
+    const line2 = bufferService.buffer.lines.get(1);
+    setText(line1, 0, 'aa');
+    setUrl(line1, 2, 'bbb', 1);
+    setUrl(line2, 0, 'cccc', 1);
+    setText(line2, 4, 'x');
+    line2!.isWrapped = true;
+
+    const links = await getLinks(provider, 2);
+    assert.lengthOf(links, 1);
+    assert.deepEqual(links[0].range, {
+      start: { x: 3, y: 1 },
+      end: { x: 4, y: 2 }
+    });
+  });
+
+  it('expands a wrapped link range forward when a link ends at line boundary', async () => {
+    const line1 = bufferService.buffer.lines.get(0);
+    const line2 = bufferService.buffer.lines.get(1);
+    setUrl(line1, 0, 'aaaaa', 1);
+    setUrl(line2, 0, 'bb', 1);
+    setText(line2, 2, 'ccc');
+    line2!.isWrapped = true;
+
+    const links = await getLinks(provider, 1);
+    assert.lengthOf(links, 1);
+    assert.deepEqual(links[0].range, {
+      start: { x: 1, y: 1 },
+      end: { x: 2, y: 2 }
+    });
+  });
+
+  it('does not merge wrapped links with different url ids', async () => {
+    const line1 = bufferService.buffer.lines.get(0);
+    const line2 = bufferService.buffer.lines.get(1);
+    setUrl(line1, 0, 'aaaaa', 1);
+    setUrl(line2, 0, 'bbb', 2);
+    setText(line2, 3, 'cc');
+    line2!.isWrapped = true;
+
+    const links = await getLinks(provider, 1);
+    assert.lengthOf(links, 1);
+    assert.deepEqual(links[0].range, {
+      start: { x: 1, y: 1 },
+      end: { x: 5, y: 1 }
+    });
+  });
+});

src/browser/OscLinkProvider.ts

@@ -6,6 +6,7 @@
 import { IBufferRange, ILink } from 'browser/Types';
 import { ILinkProvider } from 'browser/services/Services';
 import { CellData } from 'common/buffer/CellData';
+import { IBufferLine } from 'common/Types';
 import { IBufferService, IOptionsService, IOscLinkService } from 'common/services/Services';
 
 export class OscLinkProvider implements ILinkProvider {
@@ -57,19 +58,8 @@ export class OscLinkProvider implements ILinkProvider {
       if (finishLink || (currentStart !== -1 && x === lineLength - 1)) {
         const text = this._oscLinkService.getLinkData(currentLinkId)?.uri;
         if (text) {
-          // These ranges are 1-based
-          const range: IBufferRange = {
-            start: {
-              x: currentStart + 1,
-              y
-            },
-            end: {
-              // Offset end x if it's a link that ends on the last cell in the line
-              x: x + (!finishLink && x === lineLength - 1 ? 1 : 0),
-              y
-            }
-          };
-
+          const endX = x + (!finishLink && x === lineLength - 1 ? 1 : 0);
+          const range = this._getRangeWithLineWrap(y, currentStart, endX, currentLinkId);
           let ignoreLink = false;
           if (!linkHandler?.allowNonHttpProtocols) {
             try {
@@ -111,6 +101,82 @@ export class OscLinkProvider implements ILinkProvider {
     //       id
     callback(result);
   }
+
+  /**
+   * Expand a single-line OSC 8 range to a contiguous wrapped range for the same link id.
+   */
+  private _getRangeWithLineWrap(y: number, startX: number, endX: number, linkId: number): IBufferRange {
+    let startY = y;
+    let finalStartX = startX;
+    let endY = y;
+    let finalEndX = endX;
+
+    // Expand upward only when this segment starts at column 0 and the current line is wrapped.
+    while (finalStartX === 0) {
+      const currentLine = this._bufferService.buffer.lines.get(startY - 1);
+      if (!currentLine?.isWrapped) {
+        break;
+      }
+      const previousLine = this._bufferService.buffer.lines.get(startY - 2);
+      if (!previousLine) {
+        break;
+      }
+      const previousLineLength = previousLine.getTrimmedLength();
+      if (previousLineLength === 0 || !this._hasUrlId(previousLine, previousLineLength - 1, linkId)) {
+        break;
+      }
+      let previousStartX = previousLineLength - 1;
+      while (previousStartX > 0 && this._hasUrlId(previousLine, previousStartX - 1, linkId)) {
+        previousStartX--;
+      }
+      startY--;
+      finalStartX = previousStartX;
+    }
+
+    // Expand downward only when this segment reaches trimmed EOL and the next line is wrapped.
+    while (true) {
+      const currentLine = this._bufferService.buffer.lines.get(endY - 1);
+      if (!currentLine) {
+        break;
+      }
+      const currentLineLength = currentLine.getTrimmedLength();
+      if (finalEndX !== currentLineLength) {
+        break;
+      }
+      const nextLine = this._bufferService.buffer.lines.get(endY);
+      if (!nextLine?.isWrapped) {
+        break;
+      }
+      const nextLineLength = nextLine.getTrimmedLength();
+      if (nextLineLength === 0 || !this._hasUrlId(nextLine, 0, linkId)) {
+        break;
+      }
+      let nextEndX = 1;
+      while (nextEndX < nextLineLength && this._hasUrlId(nextLine, nextEndX, linkId)) {
+        nextEndX++;
+      }
+      endY++;
+      finalEndX = nextEndX;
+    }
+
+    // IBufferRange uses 1-based coordinates.
+    return {
+      start: {
+        x: finalStartX + 1,
+        y: startY
+      },
+      end: {
+        x: finalEndX,
+        y: endY
+      }
+    };
+  }
+
+  private _hasUrlId(line: IBufferLine, x: number, linkId: number): boolean {
+    const cell = this._workCell;
+    line.loadCell(x, cell);
+    return !!cell.hasExtendedAttrs() && cell.extended.urlId === linkId;
+  }
 }
 
 function defaultActivate(e: MouseEvent, uri: string): void {

src/browser/REARCHITECTURE.md

@@ -0,0 +1,173 @@
+# Browser folder rearchitecture
+
+Composite TypeScript projects with enforced dependencies, mirroring the layered layout planned for `src/common/`.
+
+## Platform layer rule
+
+A module is **platform** only if **no class** in that project has a **service** injected via its constructor. That includes:
+
+- Common services (`@IBufferService`, `@IOptionsService`, `@ICoreService`, `@IInstantiationService`, etc.)
+- Browser services (`@ICoreBrowserService`, `@IRenderService`, `@IThemeService`, `@ICharSizeService`, …)
+
+Passing a service into a **function** (e.g. `moveToCellSequence(…, bufferService)`) is fine. `new TextBlinkStateManager(…, coreBrowserService, optionsService)` is not — that class belongs in integration.
+
+Interface-only modules (`browser/selection/Types.ts`, `renderer/shared/Types.ts`) are platform. Implementations that take services are not.
+
+## Dependency graph (corrected)
+
+```mermaid
+flowchart BT
+  subgraph platform["Platform layer — no ctor service injection"]
+    direction LR
+    base["browser/base"]
+    scrollable["browser/scrollable"]
+    input["browser/input"]
+    selectionTypes["browser/selection/types"]
+    renderCore["browser/renderer/core"]
+    decorStore["browser/decorations/store"]
+
+    scrollable --> base
+    input --> base
+    selectionTypes --> base
+    renderCore --> base
+    decorStore --> base
+  end
+
+  subgraph integration["Integration layer — DI and wiring"]
+    direction LR
+    services["browser/services"]
+    renderer["browser/renderer"]
+    decorations["browser/decorations"]
+    terminal["browser/terminal"]
+
+    services --> base
+    services --> input
+    services --> selectionTypes
+    services --> renderCore
+    services --> decorStore
+    renderer --> services
+    renderer --> renderCore
+    renderer --> base
+    decorations --> services
+    decorations --> decorStore
+    decorations --> renderCore
+    terminal --> services
+    terminal --> renderer
+    terminal --> decorations
+    terminal --> input
+    terminal --> scrollable
+    terminal --> base
+  end
+
+  subgraph api_layer["API layer"]
+    public["browser/public"]
+  end
+
+  integration --> platform
+  api_layer --> integration
+
+  public --> terminal
+```
+
+`browser/renderer` is **not** platform: it owns `DomRenderer`, `DomRendererRowFactory`, and `TextBlinkStateManager`, all of which take injected services.
+
+## Constructor audit (current tree)
+
+### Platform-eligible
+
+| Location | Type | Notes |
+| --- | --- | --- |
+| `Dom.ts`, `Types.ts`, `LocalizableStrings.ts`, `ColorContrastCache.ts`, `TimeBasedDebouncer.ts`, `shared/` | classes / functions | no DI |
+| `scrollable/**` | widgets | `touch.ts` uses `Dom` only |
+| `input/Mouse.ts` | functions | pure DOM math |
+| `input/MoveToCell.ts` | functions | `IBufferService` passed as argument, not ctor-injected |
+| `selection/Types.ts` | interfaces | no classes with DI |
+| `renderer/shared/Constants.ts`, `RendererUtils.ts`, `Types.ts`, `SelectionRenderModel.ts` | classes | no DI |
+| `renderer/dom/WidthCache.ts` | class | canvas factory only, no services |
+| `decorations/ColorZoneStore.ts` | class | common types only, no DI |
+
+### Integration-only (ctor service injection)
+
+| Location | Injected services (representative) |
+| --- | --- |
+| `selection/SelectionModel.ts` | `IBufferService` |
+| `input/CompositionHelper.ts` | `IBufferService`, `IOptionsService`, `ICoreService`, `IRenderService` |
+| `renderer/shared/TextBlinkStateManager.ts` | `ICoreBrowserService`, `IOptionsService` |
+| `renderer/dom/DomRendererRowFactory.ts` | `ICharacterJoinerService`, `IOptionsService`, `ICoreBrowserService`, `ICoreService`, `IDecorationService`, `IThemeService` |
+| `renderer/dom/DomRenderer.ts` | `IInstantiationService`, `ICharSizeService`, `IOptionsService`, `IBufferService`, `ICoreService`, `ICoreBrowserService`, `IThemeService`; creates `DomRendererRowFactory` via `IInstantiationService` |
+| `renderer/dom/DomRenderer` inner `CursorBlinkStateManager` | `ICoreBrowserService` |
+| `services/**` | common + browser services (all `@…` ctor params) |
+| `RenderDebouncer.ts` | `ICoreBrowserService` |
+| `decorations/BufferDecorationRenderer.ts`, `OverviewRulerRenderer.ts` | `IBufferService`, `ICoreBrowserService`, `IDecorationService`, `IRenderService`, `IThemeService`, … |
+| `Viewport.ts`, `Linkifier.ts`, `AccessibilityManager.ts`, `OscLinkProvider.ts` | multiple common + browser services |
+| `CoreBrowserTerminal.ts` | orchestrates service registration and renderer construction |
+
+`Clipboard.ts` has no class ctor DI; handlers receive `ISelectionService` at call sites — keep with `terminal`.
+
+## Target package layout
+
+### Platform
+
+| Project | Contents |
+| --- | --- |
+| `browser/base` | `Dom`, `Types`, `LocalizableStrings`, `ColorContrastCache`, `TimeBasedDebouncer`, `shared/`; browser **service interfaces** (extracted from `services/Services.ts`) |
+| `browser/scrollable` | `scrollable/**` |
+| `browser/input` | `Mouse.ts`, `MoveToCell.ts` only |
+| `browser/selection/types` | `selection/Types.ts` (or merge into `base` if preferred) |
+| `browser/renderer/core` | `renderer/shared/{Constants,RendererUtils,Types,SelectionRenderModel}.ts`, `renderer/dom/WidthCache.ts` |
+| `browser/decorations/store` | `ColorZoneStore.ts` |
+
+`SelectionModel` moves to **`browser/services`** (only consumer is `SelectionService`).
+
+`CompositionHelper` moves to **`browser/terminal`** (or `browser/input/ime` as integration sibling).
+
+`TextBlinkStateManager`, `DomRenderer`, `DomRendererRowFactory` move to **`browser/renderer`** (integration), depending on **`browser/services`**.
+
+### Integration
+
+| Project | Contents |
+| --- | --- |
+| `browser/services` | `services/**`, `selection/SelectionModel.ts`, `RenderDebouncer.ts` |
+| `browser/renderer` | `TextBlinkStateManager.ts`, `renderer/dom/DomRenderer.ts`, `DomRendererRowFactory.ts` (+ tests) |
+| `browser/decorations` | `BufferDecorationRenderer.ts`, `OverviewRulerRenderer.ts` |
+| `browser/terminal` | `CoreBrowserTerminal.ts`, `Viewport.ts`, `Linkifier.ts`, `Clipboard.ts`, `AccessibilityManager.ts`, `OscLinkProvider.ts`, `CompositionHelper.ts` |
+
+### API
+
+| Project | Contents |
+| --- | --- |
+| `browser/public` | `public/Terminal.ts` |
+
+## Build order
+
+1. `base`, `scrollable`, `input`, `selection/types`, `renderer/core`, `decorations/store`
+2. `services`
+3. `renderer`, `decorations`
+4. `terminal`
+5. `public`
+
+## Why `renderer/dom` is not platform
+
+`DomRenderer` (abbreviated):
+
+```ts
+constructor(
+  …,
+  @IInstantiationService instantiationService: IInstantiationService,
+  @ICharSizeService private readonly _charSizeService: ICharSizeService,
+  @IOptionsService private readonly _optionsService: IOptionsService,
+  @IBufferService private readonly _bufferService: IBufferService,
+  @ICoreService private readonly _coreService: ICoreService,
+  @ICoreBrowserService private readonly _coreBrowserService: ICoreBrowserService,
+  @IThemeService private readonly _themeService: IThemeService
+) {
+  this._rowFactory = instantiationService.createInstance(DomRendererRowFactory, document);
+  this._textBlinkStateManager = this._register(new TextBlinkStateManager(…, this._coreBrowserService, this._optionsService));
+}
+```
+
+`DomRendererRowFactory` similarly injects `ICharacterJoinerService`, `ICoreBrowserService`, `IThemeService`, and other services. So **`renderer/dom` → `browser/services`** (and common services) today; the corrected graph places the whole DOM renderer stack in integration, with only `WidthCache` left in `renderer/core`.
+
+## Parity with `common/`
+
+Common platform modules contain algorithms and data structures without terminal service wiring. Browser platform modules are the same: DOM/scroll utilities, pointer math, renderer **primitives** (`WidthCache`, selection render geometry), and shared types — not renderers or IME helpers that pull `IRenderService` / `IThemeService` from DI.

src/browser/Terminal2.test.ts

@@ -14,7 +14,7 @@ import { IDisposable } from '@xterm/xterm';
 const COLS = 80;
 const ROWS = 25;
 
-const escapeSequenceFilesDir = path.join(__dirname, '../../fixtures/escape_sequence_files');
+const escapeSequenceFilesDir = path.join(__dirname, '../../test/fixtures/escape_sequence_files');
 const TESTFILES = fs.readdirSync(escapeSequenceFilesDir)
   .filter(f => f.endsWith('.in'))
   .map(f => path.join(escapeSequenceFilesDir, f));
@@ -125,7 +125,7 @@ function formatError(input: string, output: string, expected: string): string {
 // simple debug output of terminal cells
 function terminalToString(term: CoreBrowserTerminal): string {
   let result = '';
-  let lineText = '';
+  let lineText: string;
   for (let line = term.buffer.ybase; line < term.buffer.ybase + term.rows; line++) {
     lineText = term.buffer.lines.get(line)!.translateToString(true);
     // rtrim empty cells as xterm does

src/browser/renderer/dom/DomRendererRowFactory.ts

@@ -90,14 +90,14 @@ export class DomRendererRowFactory {
     let charElement: HTMLSpanElement | undefined;
     let cellAmount = 0;
     let text = '';
-    let i = 0;
+    let i;
     let oldBg = 0;
     let oldFg = 0;
     let oldExt = 0;
     let oldLinkHover: number | boolean = false;
     let oldSpacing = 0;
     let oldIsInSelection: boolean = false;
-    let spacing = 0;
+    let spacing;
     let skipJoinedCheckUntilX = 0;
     const classes: string[] = [];
 
@@ -231,6 +231,7 @@ export class DomRendererRowFactory {
           }
           charElement = this._document.createElement('span');
           cellAmount = 0;
+          // eslint-disable-next-line no-useless-assignment
           text = '';
         }
       }

src/browser/renderer/dom/WidthCache.ts

@@ -110,7 +110,7 @@ export class WidthCache implements IDisposable {
    * `variant` denotes the font variant to be used.
    */
   public get(c: string, bold: boolean | number, italic: boolean | number): number {
-    let cp = 0;
+    let cp: number;
     if (!bold && !italic && c.length === 1 && (cp = c.charCodeAt(0)) < WidthCacheSettings.FLAT_SIZE) {
       if (this._flat[cp] !== WidthCacheSettings.FLAT_UNSET) {
         return this._flat[cp];

src/browser/scrollable/touch.ts

@@ -367,7 +367,7 @@ export class Gesture extends Disposable {
   private _dispatchEvent(event: IGestureEvent): void {
     if (event.type === EventType.TAP) {
       const currentTime = (new Date()).getTime();
-      let setTapCount = 0;
+      let setTapCount;
       if (currentTime - this._lastSetTapCountTime > Gesture._clearTapCountTime) {
         setTapCount = 1;
       } else {

src/browser/services/CharacterJoinerService.test.ts

@@ -285,7 +285,7 @@ function substringJoiner(substring: string): (sequence: string) => [number, numb
   return (sequence: string): [number, number][] => {
     const ranges: [number, number][] = [];
     let searchIndex = 0;
-    let matchIndex = -1;
+    let matchIndex;
 
     while ((matchIndex = sequence.indexOf(substring, searchIndex)) !== -1) {
       const matchEndIndex = matchIndex + substring.length;

src/browser/services/MouseService.test.ts

@@ -3,10 +3,11 @@
  * @license MIT
  */
 import { assert } from 'chai';
-import { MouseService } from 'browser/services/MouseService';
+import { AltMouseCursorController, MouseEventCssClasses, MouseService } from 'browser/services/MouseService';
 import { MouseStateService } from 'common/services/MouseStateService';
 import { CoreMouseAction, CoreMouseButton } from 'common/Types';
 import { IBufferService, ICoreService, ILogService, IOptionsService } from 'common/services/Services';
+import { OptionsService } from 'common/services/OptionsService';
 import { MockCoreBrowserService, MockRenderService, MockSelectionService } from 'browser/TestUtils.test';
 
 function toBytes(s: string | undefined): number[] {
@@ -42,6 +43,36 @@ const logService: ILogService = {
   error: () => {}
 } as any;
 
+class TestSelectionService extends MockSelectionService {
+  public enableCount = 0;
+  public disableCount = 0;
+
+  public override enable(): void {
+    this.enableCount++;
+  }
+
+  public override disable(): void {
+    this.disableCount++;
+  }
+
+  public override shouldForceSelection(): boolean {
+    return false;
+  }
+}
+
+function createTestMouseTargetElement(): HTMLElement {
+  const classes = new Set<string>();
+  return {
+    classList: {
+      add: (className: string) => classes.add(className),
+      remove: (className: string) => classes.delete(className),
+      contains: (className: string) => classes.has(className)
+    },
+    addEventListener: () => {},
+    removeEventListener: () => {}
+  } as any;
+}
+
 describe('MouseService _triggerMouseEvent', () => {
   let mouseService: MouseService;
   let mouseStateService: MouseStateService;
@@ -211,3 +242,112 @@ describe('MouseService _triggerMouseEvent', () => {
     reports = [];
   });
 });
+
+describe('MouseService mouseEventsRequireAlt', () => {
+  it('should update selection state and cursor class when toggled while mouse events are active', () => {
+    const mouseStateService = new MouseStateService();
+    const optionsService = new OptionsService({});
+    const selectionService = new TestSelectionService();
+    const mouseService = new MouseService(
+      new MockRenderService(),
+      {
+        getMouseReportCoords: (_ev: MouseEvent, _el: HTMLElement) => ({ col: 0, row: 0, x: 0, y: 0 })
+      } as any,
+      mouseStateService,
+      {
+        triggerDataEvent: () => {},
+        triggerBinaryEvent: () => {},
+        decPrivateModes: { applicationCursorKeys: false }
+      } as any,
+      bufferService,
+      optionsService,
+      selectionService,
+      logService,
+      new MockCoreBrowserService()
+    );
+    const element = createTestMouseTargetElement();
+    const screenElement = createTestMouseTargetElement();
+    const document = {
+      addEventListener: () => {},
+      removeEventListener: () => {}
+    } as any;
+
+    mouseService.bindMouse({
+      element,
+      screenElement,
+      document
+    }, disposable => disposable, () => {});
+
+    mouseStateService.activeProtocol = 'ANY';
+    assert.isTrue(element.classList.contains(MouseEventCssClasses.ENABLE_MOUSE_EVENTS));
+    assert.equal(selectionService.disableCount, 1);
+
+    optionsService.options.mouseEventsRequireAlt = true;
+    assert.isFalse(element.classList.contains(MouseEventCssClasses.ENABLE_MOUSE_EVENTS));
+    assert.equal(selectionService.enableCount, 2);
+
+    optionsService.options.mouseEventsRequireAlt = false;
+    assert.isTrue(element.classList.contains(MouseEventCssClasses.ENABLE_MOUSE_EVENTS));
+    assert.equal(selectionService.disableCount, 2);
+  });
+
+  it('should strip alt modifier from forwarded mouse reports', () => {
+    const mouseStateService = new MouseStateService();
+    mouseStateService.activeProtocol = 'ANY';
+    mouseStateService.activeEncoding = 'SGR';
+    const optionsService = new OptionsService({ mouseEventsRequireAlt: true });
+    const reports: string[] = [];
+    const mouseService = new MouseService(
+      new MockRenderService(),
+      {
+        getMouseReportCoords: () => ({ col: 0, row: 0, x: 0, y: 0 })
+      } as any,
+      mouseStateService,
+      {
+        triggerDataEvent: (data: string) => reports.push(data),
+        triggerBinaryEvent: () => {},
+        decPrivateModes: { applicationCursorKeys: false }
+      } as any,
+      bufferService,
+      optionsService,
+      new TestSelectionService(),
+      logService,
+      new MockCoreBrowserService()
+    );
+    const ctx = {
+      target: {
+        screenElement: createTestMouseTargetElement()
+      },
+      requestedEvents: {}
+    } as any;
+
+    const sent = (mouseService as any)._sendEvent(ctx, {
+      type: 'mousedown',
+      button: 0,
+      altKey: true,
+      ctrlKey: false,
+      shiftKey: false
+    } as MouseEvent);
+
+    assert.isTrue(sent);
+    assert.deepEqual(reports, ['\x1b[<0;1;1M']);
+  });
+
+  it('should toggle enable-mouse-events class when alt modifier changes', () => {
+    const element = createTestMouseTargetElement();
+    const altMouseCursor = new AltMouseCursorController(element, {
+      addEventListener: () => {},
+      removeEventListener: () => {}
+    } as any, () => true);
+
+    const sync = (altHeld: boolean) => altMouseCursor.syncFromModifier({
+      getModifierState: (key: string) => key === 'Alt' && altHeld
+    } as KeyboardEvent);
+
+    assert.isFalse(element.classList.contains(MouseEventCssClasses.ENABLE_MOUSE_EVENTS));
+    sync(true);
+    assert.isTrue(element.classList.contains(MouseEventCssClasses.ENABLE_MOUSE_EVENTS));
+    sync(false);
+    assert.isFalse(element.classList.contains(MouseEventCssClasses.ENABLE_MOUSE_EVENTS));
+  });
+});

src/browser/services/MouseService.ts

@@ -7,12 +7,16 @@ import { addDisposableListener } from 'browser/Dom';
 import { IBufferService, IMouseStateService, ICoreService, ILogService, IOptionsService } from 'common/services/Services';
 import { CoreMouseAction, CoreMouseButton, CoreMouseEventType, ICoreMouseEvent, IDisposable } from 'common/Types';
 import { C0 } from 'common/data/EscapeSequences';
-import { toDisposable } from 'common/Lifecycle';
+import { DisposableStore, MutableDisposable, toDisposable } from 'common/Lifecycle';
 import { ICoreBrowserService, IMouseCoordsService, IMouseService, IMouseServiceTarget, IRenderService, ISelectionService } from './Services';
 import { Gesture, EventType as GestureEventType, IGestureEvent } from 'browser/scrollable/touch';
 
 type RequestedMouseEvents = Record<'mouseup' | 'wheel' | 'mousedrag' | 'mousemove', EventListener | null>;
 
+export const enum MouseEventCssClasses {
+  ENABLE_MOUSE_EVENTS = 'enable-mouse-events'
+}
+
 interface IMouseBindContext {
   readonly target: IMouseServiceTarget;
   readonly focus: () => void;
@@ -25,6 +29,7 @@ export class MouseService implements IMouseService {
   private _lastEvent: ICoreMouseEvent | null = null;
   private _wheelPartialScroll: number = 0;
   private _touchScrollAccumulator: number = 0;
+  private _altMouseCursor: AltMouseCursorController | undefined;
 
   constructor(
     @IRenderService private readonly _renderService: IRenderService,
@@ -63,9 +68,20 @@ export class MouseService implements IMouseService {
       mousedrag: (ev: Event) => this._handleMouseDrag(ctx, ev as MouseEvent),
       mousemove: (ev: Event) => this._handleMouseMove(ctx, ev as MouseEvent)
     };
+    this._altMouseCursor = new AltMouseCursorController(
+      element,
+      document,
+      () => this._mouseStateService.areMouseEventsActive
+        && !!this._optionsService.rawOptions.mouseEventsRequireAlt
+    );
+    register(this._altMouseCursor);
     register(this._mouseStateService.onProtocolChange(events => {
       this._handleProtocolChange(ctx, eventListeners, events);
     }));
+    register(this._optionsService.onSpecificOptionChange('mouseEventsRequireAlt', () => {
+      this._syncMouseModeState(element);
+      this._altMouseCursor?.sync();
+    }));
     // force initial onProtocolChange so we dont miss early mouse requests
     this._mouseStateService.activeProtocol = this._mouseStateService.activeProtocol;
 
@@ -153,6 +169,19 @@ export class MouseService implements IMouseService {
       return false;
     }
 
+    if (but !== CoreMouseButton.WHEEL
+      && this._optionsService.rawOptions.mouseEventsRequireAlt
+      && this._mouseStateService.areMouseEventsActive
+      && !ev.altKey) {
+      return false;
+    }
+
+    // Alt is only used locally to gate mouse passthrough; do not forward it to the
+    // application (e.g. tmux ignores alt-modified mouse reports).
+    const stripAltFromReport = but !== CoreMouseButton.WHEEL
+      && this._optionsService.rawOptions.mouseEventsRequireAlt
+      && this._mouseStateService.areMouseEventsActive;
+
     return this._triggerMouseEvent({
       col: pos.col,
       row: pos.row,
@@ -161,7 +190,7 @@ export class MouseService implements IMouseService {
       button: but,
       action,
       ctrl: ev.ctrlKey,
-      alt: ev.altKey,
+      alt: stripAltFromReport ? false : ev.altKey,
       shift: ev.shiftKey
     });
   }
@@ -353,6 +382,21 @@ export class MouseService implements IMouseService {
     this._touchScrollAccumulator = 0;
   }
 
+  private _syncMouseModeState(element: HTMLElement): void {
+    if (this._mouseStateService.areMouseEventsActive) {
+      if (this._optionsService.rawOptions.mouseEventsRequireAlt) {
+        this._altMouseCursor?.resetClass();
+        this._selectionService.enable();
+      } else {
+        element.classList.add(MouseEventCssClasses.ENABLE_MOUSE_EVENTS);
+        this._selectionService.disable();
+      }
+    } else {
+      element.classList.remove(MouseEventCssClasses.ENABLE_MOUSE_EVENTS);
+      this._selectionService.enable();
+    }
+  }
+
   private _handleProtocolChange(ctx: IMouseBindContext, eventListeners: Record<'mouseup' | 'wheel' | 'mousedrag' | 'mousemove', EventListener>, events: CoreMouseEventType): void {
     const { element, document } = ctx.target;
     const { requestedEvents } = ctx;
@@ -361,13 +405,11 @@ export class MouseService implements IMouseService {
       if (this._optionsService.rawOptions.logLevel === 'debug') {
         this._logService.debug('Binding to mouse events:', this._explainEvents(events));
       }
-      element.classList.add('enable-mouse-events');
-      this._selectionService.disable();
     } else {
       this._logService.debug('Unbinding from mouse events.');
-      element.classList.remove('enable-mouse-events');
-      this._selectionService.enable();
     }
+    this._syncMouseModeState(element);
+    this._altMouseCursor?.sync();
 
     // add/remove handlers from requestedEvents
     if (!(events & CoreMouseEventType.MOVE)) {
@@ -537,3 +579,64 @@ export class MouseService implements IMouseService {
   }
 
 }
+
+/**
+ * Toggles MouseEventCssClasses.ENABLE_MOUSE_EVENTS on the terminal element while alt is held when
+ * `mouseEventsRequireAlt` is active. DOM listeners are only registered while active.
+ */
+export class AltMouseCursorController implements IDisposable {
+  private readonly _listeners = new MutableDisposable<IDisposable>();
+
+  constructor(
+    private readonly _element: HTMLElement,
+    private readonly _document: Document,
+    private readonly _isActive: () => boolean
+  ) {
+  }
+
+  public dispose(): void {
+    this._listeners.dispose();
+  }
+
+  public sync(): void {
+    this._listeners.clear();
+
+    if (!this._isActive()) {
+      return;
+    }
+
+    const store = new DisposableStore();
+    const syncFromModifier = (ev: KeyboardEvent | MouseEvent): void => this.syncFromModifier(ev);
+    store.add(addDisposableListener(this._document, 'keydown', syncFromModifier));
+    store.add(addDisposableListener(this._document, 'keyup', syncFromModifier));
+    store.add(addDisposableListener(this._element, 'mousemove', syncFromModifier));
+    const targetWindow = this._element.ownerDocument?.defaultView;
+    if (targetWindow) {
+      store.add(addDisposableListener(targetWindow, 'blur', () => {
+        if (this._isActive()) {
+          this.resetClass();
+        }
+      }));
+    }
+    this._listeners.value = store;
+  }
+
+  public resetClass(): void {
+    this._updateClass(false);
+  }
+
+  public syncFromModifier(ev: KeyboardEvent | MouseEvent): void {
+    if (!this._isActive()) {
+      return;
+    }
+    this._updateClass(ev.getModifierState('Alt'));
+  }
+
+  private _updateClass(altHeld: boolean): void {
+    if (altHeld) {
+      this._element.classList.add(MouseEventCssClasses.ENABLE_MOUSE_EVENTS);
+    } else {
+      this._element.classList.remove(MouseEventCssClasses.ENABLE_MOUSE_EVENTS);
+    }
+  }
+}

src/browser/services/SelectionService.test.ts

@@ -7,7 +7,7 @@ import { assert } from 'chai';
 import { SelectionService, SelectionMode } from './SelectionService';
 import { SelectionModel } from 'browser/selection/SelectionModel';
 import { IBufferLine } from 'common/Types';
-import { MockBufferService, MockOptionsService, MockCoreService, createCellData } from 'common/TestUtils.test';
+import { MockBufferService, MockOptionsService, MockCoreService, MockMouseStateService, createCellData } from 'common/TestUtils.test';
 import { BufferLine } from 'common/buffer/BufferLine';
 import { BufferLineStringCache } from 'common/buffer/BufferLineStringCache';
 import { IBufferService, IOptionsService } from 'common/services/Services';
@@ -22,9 +22,10 @@ class TestSelectionService extends SelectionService {
   constructor(
     bufferService: IBufferService,
     optionsService: IOptionsService,
-    renderService: IRenderService
+    renderService: IRenderService,
+    public readonly mouseStateService: MockMouseStateService
   ) {
-    super(null!, null!, null!, bufferService, new MockCoreService(), new MockMouseService(), optionsService, renderService, new MockCoreBrowserService());
+    super(null!, null!, null!, bufferService, new MockCoreService(), new MockMouseService(), optionsService, mouseStateService, renderService, new MockCoreBrowserService());
   }
 
   public get model(): SelectionModel { return this._model; }
@@ -45,16 +46,18 @@ describe('SelectionService', () => {
   let buffer: IBuffer;
   let bufferService: IBufferService;
   let optionsService: IOptionsService;
+  let mouseStateService: MockMouseStateService;
   let selectionService: TestSelectionService;
 
   beforeEach(() => {
     optionsService = new MockOptionsService();
+    mouseStateService = new MockMouseStateService();
     bufferService = new MockBufferService(20, 20, optionsService);
     buffer = bufferService.buffer;
     const renderService = new MockRenderService();
     renderService.dimensions.css.canvas.height = 10 * 20;
     renderService.dimensions.css.canvas.width = 10 * 20;
-    selectionService = new TestSelectionService(bufferService, optionsService, renderService);
+    selectionService = new TestSelectionService(bufferService, optionsService, renderService, mouseStateService);
   });
 
   function stringToRow(text: string): IBufferLine {
@@ -499,5 +502,21 @@ describe('SelectionService', () => {
       assert.isFalse(selectionService.areCoordsInSelection([2, 1], [2, 0], [2, 1]));
     });
   });
+
+  describe('shouldForceSelection', () => {
+    it('should force selection without alt when mouseEventsRequireAlt is enabled', () => {
+      optionsService.options.mouseEventsRequireAlt = true;
+      mouseStateService.areMouseEventsActive = true;
+      assert.isTrue(selectionService.shouldForceSelection({ altKey: false } as MouseEvent));
+      assert.isFalse(selectionService.shouldForceSelection({ altKey: true } as MouseEvent));
+    });
+
+    it('should take precedence over macOptionClickForcesSelection', () => {
+      optionsService.options.mouseEventsRequireAlt = true;
+      optionsService.options.macOptionClickForcesSelection = true;
+      mouseStateService.areMouseEventsActive = true;
+      assert.isFalse(selectionService.shouldForceSelection({ altKey: true } as MouseEvent));
+    });
+  });
 });
 

src/browser/services/SelectionService.ts

@@ -9,13 +9,13 @@ import { moveToCellSequence } from 'browser/input/MoveToCell';
 import { SelectionModel } from 'browser/selection/SelectionModel';
 import { ISelectionRedrawRequestEvent, ISelectionRequestScrollLinesEvent } from 'browser/selection/Types';
 import { ICoreBrowserService, IMouseCoordsService, IRenderService, ISelectionService } from 'browser/services/Services';
-import { Disposable, toDisposable } from 'common/Lifecycle';
+import { Disposable, MutableDisposable, toDisposable } from 'common/Lifecycle';
 import * as Browser from 'common/Platform';
 import { IBufferLine, ICellData, IDisposable } from 'common/Types';
 import { getRangeLength } from 'common/buffer/BufferRange';
 import { CellData } from 'common/buffer/CellData';
 import { IBuffer } from 'common/buffer/Types';
-import { IBufferService, ICoreService, IOptionsService } from 'common/services/Services';
+import { IBufferService, ICoreService, IMouseStateService, IOptionsService } from 'common/services/Services';
 import { Emitter } from 'common/Event';
 
 const enum Constants {
@@ -102,7 +102,7 @@ export class SelectionService extends Disposable implements ISelectionService {
 
   private _mouseMoveListener: EventListener;
   private _mouseUpListener: EventListener;
-  private _trimListener: IDisposable;
+  private readonly _trimListener = this._register(new MutableDisposable<IDisposable>());
   private _workCell: CellData = new CellData();
 
   private _mouseDownTimeStamp: number = 0;
@@ -127,6 +127,7 @@ export class SelectionService extends Disposable implements ISelectionService {
     @ICoreService private readonly _coreService: ICoreService,
     @IMouseCoordsService private readonly _mouseCoordsService: IMouseCoordsService,
     @IOptionsService private readonly _optionsService: IOptionsService,
+    @IMouseStateService private readonly _mouseStateService: IMouseStateService,
     @IRenderService private readonly _renderService: IRenderService,
     @ICoreBrowserService private readonly _coreBrowserService: ICoreBrowserService
   ) {
@@ -140,7 +141,7 @@ export class SelectionService extends Disposable implements ISelectionService {
         this.clearSelection();
       }
     });
-    this._trimListener = this._bufferService.buffer.lines.onTrim(amount => this._handleTrim(amount));
+    this._trimListener.value = this._bufferService.buffer.lines.onTrim(amount => this._handleTrim(amount));
     this._register(this._bufferService.buffers.onBufferActivate(e => this._handleBufferActivate(e)));
 
     this.enable();
@@ -434,6 +435,10 @@ export class SelectionService extends Disposable implements ISelectionService {
    * @param event The mouse event.
    */
   public shouldForceSelection(event: MouseEvent): boolean {
+    if (this._optionsService.rawOptions.mouseEventsRequireAlt && this._mouseStateService.areMouseEventsActive) {
+      return !event.altKey;
+    }
+
     if (Browser.isMac) {
       return event.altKey && this._optionsService.rawOptions.macOptionClickForcesSelection;
     }
@@ -458,6 +463,10 @@ export class SelectionService extends Disposable implements ISelectionService {
       return;
     }
 
+    if (this._optionsService.rawOptions.mouseEventsRequireAlt && this._mouseStateService.areMouseEventsActive && event.altKey) {
+      return;
+    }
+
     // Allow selection when using a specific modifier key, even when disabled
     if (!this._enabled) {
       if (!this.shouldForceSelection(event)) {
@@ -596,6 +605,9 @@ export class SelectionService extends Disposable implements ISelectionService {
    * @param event the mouse or keyboard event
    */
   public shouldColumnSelect(event: KeyboardEvent | MouseEvent): boolean {
+    if (this._optionsService.rawOptions.mouseEventsRequireAlt && this._mouseStateService.areMouseEventsActive) {
+      return false;
+    }
     return event.altKey && !(Browser.isMac && this._optionsService.rawOptions.macOptionClickForcesSelection);
   }
 
@@ -769,8 +781,7 @@ export class SelectionService extends Disposable implements ISelectionService {
     // reverseIndex) and delete in a splice is only ever used when the same
     // number of elements was just added. Given this is could actually be
     // beneficial to leave the selection as is for these cases.
-    this._trimListener.dispose();
-    this._trimListener = e.activeBuffer.lines.onTrim(amount => this._handleTrim(amount));
+    this._trimListener.value = e.activeBuffer.lines.onTrim(amount => this._handleTrim(amount));
   }
 
   /**
@@ -919,10 +930,10 @@ export class SelectionService extends Disposable implements ISelectionService {
     // Calculate the start _column_, converting the the string indexes back to
     // column coordinates.
     let start =
-        startIndex // The index of the selection's start char in the line string
-        + charOffset // The difference between the initial char's column and index
-        - leftWideCharCount // The number of wide chars left of the initial char
-        + leftLongCharOffset; // The number of additional chars left of the initial char added by columns with strings longer than 1 (emojis)
+      startIndex // The index of the selection's start char in the line string
+      + charOffset // The difference between the initial char's column and index
+      - leftWideCharCount // The number of wide chars left of the initial char
+      + leftLongCharOffset; // The number of additional chars left of the initial char added by columns with strings longer than 1 (emojis)
 
     // Calculate the length in _columns_, converting the the string indexes back
     // to column coordinates.

src/common/Clone.test.ts

@@ -1,129 +0,0 @@
-/**
- * Copyright (c) 2016 The xterm.js authors. All rights reserved.
- * @license MIT
- */
-
-import { assert } from 'chai';
-import { clone } from 'common/Clone';
-
-describe('clone', () => {
-  it('should clone simple objects', () => {
-    const test = {
-      a: 1,
-      b: 2
-    };
-
-    assert.deepEqual(clone(test), { a: 1, b: 2 });
-  });
-
-  it('should clone nested objects', () => {
-    const test = {
-      bar: {
-        a: 1,
-        b: 2,
-        c: {
-          foo: 'bar'
-        }
-      }
-    };
-
-    assert.deepEqual(clone(test), {
-      bar: {
-        a: 1,
-        b: 2,
-        c: {
-          foo: 'bar'
-        }
-      }
-    });
-  });
-
-  it('should clone array values', () => {
-    const test = {
-      a: [1, 2, 3],
-      b: [1, null, 'test', { foo: 'bar' }]
-    };
-
-    assert.deepEqual(clone(test), {
-      a: [1, 2, 3],
-      b: [1, null, 'test', { foo: 'bar' }]
-    });
-  });
-
-  it('should stop mutation from occuring on the original object', () => {
-    const test = {
-      a: 1,
-      b: 2,
-      c: {
-        foo: 'bar'
-      }
-    };
-
-    const cloned = clone(test);
-
-    test.a = 5;
-    test.c.foo = 'barbaz';
-
-    assert.deepEqual(cloned, {
-      a: 1,
-      b: 2,
-      c: {
-        foo: 'bar'
-      }
-    });
-  });
-
-  it('should clone to a maximum depth of 5 by default', () => {
-    const test = {
-      a: {
-        b: {
-          c: {
-            d: {
-              e: {
-                f: 'foo'
-              }
-            }
-          }
-        }
-      }
-    };
-
-    const cloned = clone(test);
-
-    test.a.b.c.d.e.f = 'bar';
-
-    // The values at a greater depth then 5 should not be cloned
-    assert.equal((cloned as any).a.b.c.d.e.f, 'bar');
-  });
-
-  it('should allow an optional maximum depth to be set', () => {
-    const test = {
-      a: {
-        b: {
-          c: 'foo'
-        }
-      }
-    };
-
-    const cloned = clone(test, 2);
-
-    test.a.b.c = 'bar';
-
-    // The values at a greater depth then 2 should not be cloned
-    assert.equal((cloned as any).a.b.c, 'bar');
-  });
-
-  it('should not throw when cloning a recursive reference', () => {
-    const test = {
-      a: {
-        b: {
-          c: {}
-        }
-      }
-    };
-
-    test.a.b.c = test;
-
-    assert.doesNotThrow(() => clone(test));
-  });
-});

src/common/Clone.ts

@@ -1,23 +0,0 @@
-/**
- * Copyright (c) 2016 The xterm.js authors. All rights reserved.
- * @license MIT
- */
-
-/*
- * A simple utility for cloning values
- */
-export function clone<T>(val: T, depth: number = 5): T {
-  if (typeof val !== 'object') {
-    return val;
-  }
-
-  // If we're cloning an array, use an array as the base, otherwise use an object
-  const clonedObject: any = Array.isArray(val) ? [] : {};
-
-  for (const key in val) {
-    // Recursively clone eack item unless we're at the maximum depth
-    clonedObject[key] = depth <= 1 ? val[key] : (val[key] && clone(val[key], depth - 1));
-  }
-
-  return clonedObject as T;
-}

src/common/CoreTerminal.ts

@@ -263,7 +263,7 @@ export abstract class CoreTerminal extends Disposable implements ICoreTerminal {
   private _handleWindowsPtyOptionChange(): void {
     let value = false;
     const windowsPty = this.optionsService.rawOptions.windowsPty;
-    if (windowsPty && windowsPty.buildNumber !== undefined && windowsPty.buildNumber !== undefined) {
+    if (windowsPty && windowsPty.backend !== undefined && windowsPty.buildNumber !== undefined) {
       value = !!(windowsPty.backend === 'conpty' && windowsPty.buildNumber < 21376);
     }
     if (value) {

src/common/InputHandler.test.ts

@@ -14,7 +14,6 @@ import { Params } from 'common/parser/Params';
 import { MockCoreService, MockBufferService, MockOptionsService, MockLogService, MockMouseStateService, MockCharsetService, MockUnicodeService, MockOscLinkService, extendedAttributes } from 'common/TestUtils.test';
 import { IBufferService, ICoreService, type IOscLinkService } from 'common/services/Services';
 import { DEFAULT_OPTIONS } from 'common/services/OptionsService';
-import { clone } from 'common/Clone';
 import { BufferService } from 'common/services/BufferService';
 import { CoreService } from 'common/services/CoreService';
 import { OscLinkService } from 'common/services/OscLinkService';
@@ -227,32 +226,32 @@ describe('InputHandler', () => {
       assert.equal(coreService.decPrivateModes.cursorStyle, undefined);
       assert.equal(coreService.decPrivateModes.cursorBlink, undefined);
 
-      optionsService.options = clone(DEFAULT_OPTIONS);
+      optionsService.options = structuredClone(DEFAULT_OPTIONS);
       inputHandler.setCursorStyle(Params.fromArray([1]));
       assert.equal(coreService.decPrivateModes.cursorStyle, 'block');
       assert.equal(coreService.decPrivateModes.cursorBlink, true);
 
-      optionsService.options = clone(DEFAULT_OPTIONS);
+      optionsService.options = structuredClone(DEFAULT_OPTIONS);
       inputHandler.setCursorStyle(Params.fromArray([2]));
       assert.equal(coreService.decPrivateModes.cursorStyle, 'block');
       assert.equal(coreService.decPrivateModes.cursorBlink, false);
 
-      optionsService.options = clone(DEFAULT_OPTIONS);
+      optionsService.options = structuredClone(DEFAULT_OPTIONS);
       inputHandler.setCursorStyle(Params.fromArray([3]));
       assert.equal(coreService.decPrivateModes.cursorStyle, 'underline');
       assert.equal(coreService.decPrivateModes.cursorBlink, true);
 
-      optionsService.options = clone(DEFAULT_OPTIONS);
+      optionsService.options = structuredClone(DEFAULT_OPTIONS);
       inputHandler.setCursorStyle(Params.fromArray([4]));
       assert.equal(coreService.decPrivateModes.cursorStyle, 'underline');
       assert.equal(coreService.decPrivateModes.cursorBlink, false);
 
-      optionsService.options = clone(DEFAULT_OPTIONS);
+      optionsService.options = structuredClone(DEFAULT_OPTIONS);
       inputHandler.setCursorStyle(Params.fromArray([5]));
       assert.equal(coreService.decPrivateModes.cursorStyle, 'bar');
       assert.equal(coreService.decPrivateModes.cursorBlink, true);
 
-      optionsService.options = clone(DEFAULT_OPTIONS);
+      optionsService.options = structuredClone(DEFAULT_OPTIONS);
       inputHandler.setCursorStyle(Params.fromArray([6]));
       assert.equal(coreService.decPrivateModes.cursorStyle, 'bar');
       assert.equal(coreService.decPrivateModes.cursorBlink, false);

src/common/InputHandler.ts

@@ -567,8 +567,9 @@ export class InputHandler extends Disposable implements IInputHandler {
       if (screenReaderMode) {
         this._onA11yChar.fire(stringFromCodePoint(code));
       }
-      if (this._getCurrentLinkId()) {
-        this._oscLinkService.addLineToLink(this._getCurrentLinkId(), this._activeBuffer.ybase + this._activeBuffer.y);
+      const linkId = this._getCurrentLinkId();
+      if (linkId) {
+        this._oscLinkService.addLineToLink(linkId, this._activeBuffer.ybase + this._activeBuffer.y);
       }
 
       // goto next line if ch would overflow
@@ -2590,10 +2591,6 @@ export class InputHandler extends Disposable implements IInputHandler {
    * | 3      | CMY color.                                                    | #N      |
    * | 4      | CMYK color.                                                   | #N      |
    * | 5      | Indexed (256 colors) as `Ps ; 5 ; INDEX` or `Ps : 5 : INDEX`. | #Y      |
-   *
-   *
-   * FIXME: blinking is implemented in attrs, but not working in renderers?
-   * FIXME: remove dead branch for p=100
    */
   public charAttributes(params: IParams): boolean {
     // Optimize a single SGR0.

src/common/StringBuilder.test.ts

@@ -0,0 +1,143 @@
+/**
+ * Copyright (c) 2026 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import { assert } from 'chai';
+import { LimitedStringBuilder, StringBuilder } from 'common/StringBuilder';
+
+describe('StringBuilder', () => {
+  it('should start empty', () => {
+    const builder = new StringBuilder();
+    assert.strictEqual(builder.length, 0);
+    assert.strictEqual(builder.toString(), '');
+  });
+
+  it('should append a single chunk', () => {
+    const builder = new StringBuilder();
+    builder.append('hello');
+    assert.strictEqual(builder.length, 5);
+    assert.strictEqual(builder.toString(), 'hello');
+  });
+
+  it('should join multiple chunks in order', () => {
+    const builder = new StringBuilder();
+    builder.append('foo');
+    builder.append('bar');
+    builder.append('baz');
+    assert.strictEqual(builder.length, 9);
+    assert.strictEqual(builder.toString(), 'foobarbaz');
+  });
+
+  it('should handle empty chunks', () => {
+    const builder = new StringBuilder();
+    builder.append('');
+    builder.append('a');
+    builder.append('');
+    assert.strictEqual(builder.length, 1);
+    assert.strictEqual(builder.toString(), 'a');
+  });
+
+  it('should reset accumulated data', () => {
+    const builder = new StringBuilder();
+    builder.append('hello');
+    builder.reset();
+    assert.strictEqual(builder.length, 0);
+    assert.strictEqual(builder.toString(), '');
+  });
+
+  it('should allow appending after reset', () => {
+    const builder = new StringBuilder();
+    builder.append('old');
+    builder.reset();
+    builder.append('new');
+    assert.strictEqual(builder.toString(), 'new');
+  });
+
+  it('should accumulate many small chunks without quadratic concatenation', () => {
+    const builder = new StringBuilder();
+    const chunk = 'x';
+    const count = 10000;
+    for (let i = 0; i < count; i++) {
+      builder.append(chunk);
+    }
+    assert.strictEqual(builder.length, count);
+    assert.strictEqual(builder.toString(), 'x'.repeat(count));
+  });
+});
+
+describe('LimitedStringBuilder', () => {
+  it('should expose the configured limit', () => {
+    const builder = new LimitedStringBuilder(42);
+    assert.strictEqual(builder.limit, 42);
+  });
+
+  it('should start empty', () => {
+    const builder = new LimitedStringBuilder(10);
+    assert.strictEqual(builder.length, 0);
+    assert.strictEqual(builder.toString(), '');
+  });
+
+  it('should accept data up to the limit', () => {
+    const builder = new LimitedStringBuilder(10);
+    assert.strictEqual(builder.append('12345'), false);
+    assert.strictEqual(builder.append('67890'), false);
+    assert.strictEqual(builder.length, 10);
+    assert.strictEqual(builder.toString(), '1234567890');
+  });
+
+  it('should accept a single chunk exactly at the limit', () => {
+    const builder = new LimitedStringBuilder(5);
+    assert.strictEqual(builder.append('abcde'), false);
+    assert.strictEqual(builder.length, 5);
+    assert.strictEqual(builder.toString(), 'abcde');
+  });
+
+  it('should reject data exceeding the limit and clear the buffer', () => {
+    const builder = new LimitedStringBuilder(5);
+    builder.append('abc');
+    assert.strictEqual(builder.append('def'), true);
+    assert.strictEqual(builder.length, 0);
+    assert.strictEqual(builder.toString(), '');
+  });
+
+  it('should reject a single chunk larger than the limit', () => {
+    const builder = new LimitedStringBuilder(3);
+    assert.strictEqual(builder.append('toolong'), true);
+    assert.strictEqual(builder.length, 0);
+    assert.strictEqual(builder.toString(), '');
+  });
+
+  it('should allow appending again after reset following a limit breach', () => {
+    const builder = new LimitedStringBuilder(3);
+    assert.strictEqual(builder.append('abcd'), true);
+    builder.reset();
+    assert.strictEqual(builder.append('ab'), false);
+    assert.strictEqual(builder.toString(), 'ab');
+  });
+
+  it('should accumulate many chunks before hitting the limit', () => {
+    const limit = 100;
+    const builder = new LimitedStringBuilder(limit);
+    const chunk = 'A';
+    for (let i = 0; i < limit; i++) {
+      assert.strictEqual(builder.append(chunk), false);
+    }
+    assert.strictEqual(builder.toString(), 'A'.repeat(limit));
+    assert.strictEqual(builder.append('B'), true);
+    assert.strictEqual(builder.toString(), '');
+  });
+
+  it('should reject when limit is zero and any data is appended', () => {
+    const builder = new LimitedStringBuilder(0);
+    assert.strictEqual(builder.append('a'), true);
+    assert.strictEqual(builder.length, 0);
+  });
+
+  it('should allow zero-length appends at the limit', () => {
+    const builder = new LimitedStringBuilder(0);
+    assert.strictEqual(builder.append(''), false);
+    assert.strictEqual(builder.length, 0);
+    assert.strictEqual(builder.toString(), '');
+  });
+});

src/common/StringBuilder.ts

@@ -0,0 +1,67 @@
+/**
+ * Copyright (c) 2026 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+/**
+ * Accumulates string data from multiple chunks without O(n²) string concatenation.
+ */
+export class StringBuilder {
+  private _chunks: string[] = [];
+  private _length = 0;
+
+  public get length(): number {
+    return this._length;
+  }
+
+  public reset(): void {
+    this._chunks.length = 0;
+    this._length = 0;
+  }
+
+  public append(chunk: string): void {
+    this._chunks.push(chunk);
+    this._length += chunk.length;
+  }
+
+  public toString(): string {
+    return this._chunks.join('');
+  }
+}
+
+/**
+ * String builder that rejects payloads larger than a fixed limit.
+ */
+export class LimitedStringBuilder {
+  private readonly _builder = new StringBuilder();
+
+  constructor(private readonly _limit: number) { }
+
+  public get length(): number {
+    return this._builder.length;
+  }
+
+  public get limit(): number {
+    return this._limit;
+  }
+
+  public reset(): void {
+    this._builder.reset();
+  }
+
+  /**
+   * @returns true if the limit was exceeded (buffer is cleared in that case)
+   */
+  public append(chunk: string): boolean {
+    this._builder.append(chunk);
+    if (this._builder.length > this._limit) {
+      this._builder.reset();
+      return true;
+    }
+    return false;
+  }
+
+  public toString(): string {
+    return this._builder.toString();
+  }
+}

src/common/TaskQueue.ts

@@ -74,10 +74,10 @@ abstract class TaskQueue implements ITaskQueue {
 
   private _process(deadline: ITaskDeadline): void {
     this._idleCallback = undefined;
-    let taskDuration = 0;
+    let taskDuration: number;
     let longestTask = 0;
     let lastDeadlineRemaining = deadline.timeRemaining();
-    let deadlineRemaining = 0;
+    let deadlineRemaining: number;
     while (this._i < this._tasks.length) {
       taskDuration = performance.now();
       if (!this._tasks[this._i]()) {

src/common/TestUtils.test.ts

@@ -5,7 +5,6 @@
 
 import { IBufferService, ICoreService, ILogService, IOptionsService, ITerminalOptions, IMouseStateService, ICharsetService, UnicodeCharProperties, UnicodeCharWidth, IUnicodeService, IUnicodeVersionProvider, LogLevelEnum, IDecorationService, IInternalDecoration, IOscLinkService, type IBufferResizeEvent } from 'common/services/Services';
 import { UnicodeService } from 'common/services/UnicodeService';
-import { clone } from 'common/Clone';
 import { DEFAULT_OPTIONS } from 'common/services/OptionsService';
 import { IBufferSet, IBuffer } from 'common/buffer/Types';
 import { BufferSet } from 'common/buffer/BufferSet';
@@ -157,7 +156,7 @@ export class MockLogService implements ILogService {
 
 export class MockOptionsService implements IOptionsService {
   public serviceBrand: any;
-  public readonly rawOptions: Required<ITerminalOptions> = clone(DEFAULT_OPTIONS);
+  public readonly rawOptions: Required<ITerminalOptions> = structuredClone(DEFAULT_OPTIONS);
   public options: Required<ITerminalOptions> = this.rawOptions;
   public onOptionChange: IEvent<keyof ITerminalOptions> = new Emitter<keyof ITerminalOptions>().event;
   constructor(testOptions?: Partial<ITerminalOptions>) {

src/common/Types.ts

@@ -528,8 +528,8 @@ export interface IInputHandler {
   /** CSI ' } */ insertColumns(params: IParams): boolean;
   /** CSI ' ~ */ deleteColumns(params: IParams): boolean;
 
-  /** OSC 0
-      OSC 2 */ setTitle(data: string): boolean;
+  /** OSC 0 */
+  /** OSC 2 */ setTitle(data: string): boolean;
   /** OSC 4 */ setOrReportIndexedColor(data: string): boolean;
   /** OSC 10 */ setOrReportFgColor(data: string): boolean;
   /** OSC 11 */ setOrReportBgColor(data: string): boolean;
@@ -542,24 +542,24 @@ export interface IInputHandler {
   /** ESC E */ nextLine(): boolean;
   /** ESC = */ keypadApplicationMode(): boolean;
   /** ESC > */ keypadNumericMode(): boolean;
-  /** ESC % G
-      ESC % @ */ selectDefaultCharset(): boolean;
-  /** ESC ( C
-      ESC ) C
-      ESC * C
-      ESC + C
-      ESC - C
-      ESC . C
-      ESC / C */ selectCharset(collectAndFlag: string): boolean;
+  /** ESC % G */
+  /** ESC % @ */ selectDefaultCharset(): boolean;
+  /** ESC ( C */
+  /** ESC ) C */
+  /** ESC * C */
+  /** ESC + C */
+  /** ESC - C */
+  /** ESC . C */
+  /** ESC / C */ selectCharset(collectAndFlag: string): boolean;
   /** ESC D */ index(): boolean;
   /** ESC H */ tabSet(): boolean;
   /** ESC M */ reverseIndex(): boolean;
   /** ESC c */ fullReset(): boolean;
-  /** ESC n
-      ESC o
-      ESC |
-      ESC }
-      ESC ~ */ setgLevel(level: number): boolean;
+  /** ESC n */
+  /** ESC o */
+  /** ESC | */
+  /** ESC } */
+  /** ESC ~ */ setgLevel(level: number): boolean;
   /** ESC # 8 */ screenAlignmentPattern(): boolean;
 }
 

src/common/buffer/BufferLine.ts

@@ -8,6 +8,7 @@ import { AttributeData } from 'common/buffer/AttributeData';
 import { CellData } from 'common/buffer/CellData';
 import { Attributes, BgFlags, CHAR_DATA_ATTR_INDEX, CHAR_DATA_CHAR_INDEX, CHAR_DATA_WIDTH_INDEX, Content, NULL_CELL_CHAR, NULL_CELL_CODE, NULL_CELL_WIDTH, WHITESPACE_CELL_CHAR } from 'common/buffer/Constants';
 import { stringFromCodePoint } from 'common/input/TextDecoder';
+import { StringBuilder } from 'common/StringBuilder';
 
 // Buffer memory layout:
 //
@@ -41,6 +42,7 @@ export const DEFAULT_ATTR_DATA = Object.freeze(new AttributeData());
 // Work variables to avoid garbage collection
 let $startIndex = 0;
 const $workCell = new CellData();
+const $translateToStringBuilder = new StringBuilder();
 
 export interface IBufferLineStringCacheEntry {
   value: string | undefined;
@@ -570,12 +572,12 @@ export class BufferLine implements IBufferLine {
     if (outColumns) {
       outColumns.length = 0;
     }
-    let result = '';
+    $translateToStringBuilder.reset();
     while (startCol < endCol) {
       const content = this._data[startCol * Constants.CELL_INDICIES + Cell.CONTENT];
       const cp = content & Content.CODEPOINT_MASK;
       const chars = (content & Content.IS_COMBINED_MASK) ? this._combined[startCol] : (cp) ? stringFromCodePoint(cp) : WHITESPACE_CELL_CHAR;
-      result += chars;
+      $translateToStringBuilder.append(chars);
       if (outColumns) {
         for (let i = 0; i < chars.length; ++i) {
           outColumns.push(startCol);
@@ -586,6 +588,8 @@ export class BufferLine implements IBufferLine {
     if (outColumns) {
       outColumns.push(startCol);
     }
+    const result = $translateToStringBuilder.toString();
+    $translateToStringBuilder.reset();
     if (isCanonicalRequest) {
       const cacheEntry = this._getStringCacheEntry(true)!;
       cacheEntry.value = result;

src/common/buffer/BufferReflow.ts

@@ -178,7 +178,10 @@ export function reflowLargerApplyNewLayout(lines: CircularList<IBufferLine>, new
  */
 export function reflowSmallerGetNewLineLengths(wrappedLines: BufferLine[], oldCols: number, newCols: number): number[] {
   const newLineLengths: number[] = [];
-  const cellsNeeded = wrappedLines.map((l, i) => getWrappedLineTrimmedLength(wrappedLines, i, oldCols)).reduce((p, c) => p + c);
+  let cellsNeeded = 0;
+  for (let i = 0; i < wrappedLines.length; i++) {
+    cellsNeeded += getWrappedLineTrimmedLength(wrappedLines, i, oldCols);
+  }
 
   // Use srcCol and srcLine to find the new wrapping point, use that to get the cellsAvailable and
   // linesNeeded

src/common/data/Charsets.ts

@@ -98,8 +98,7 @@ CHARSETS['4'] = {
  * ESC (C or ESC (5
  * Reference: http://vt100.net/docs/vt220-rm/table2-7.html
  */
-CHARSETS['C'] =
-CHARSETS['5'] = {
+CHARSETS['C'] = CHARSETS['5'] = {
   '[': 'Ä',
   '\\': 'Ö',
   ']': 'Å',
@@ -185,8 +184,7 @@ CHARSETS['Y'] = {
  * ESC (E or ESC (6
  * Reference: http://vt100.net/docs/vt220-rm/table2-12.html
  */
-CHARSETS['E'] =
-CHARSETS['6'] = {
+CHARSETS['E'] = CHARSETS['6'] = {
   '@': 'Ä',
   '[': 'Æ',
   '\\': 'Ø',
@@ -220,8 +218,7 @@ CHARSETS['Z'] = {
  * ESC (H or ESC (7
  * Reference: http://vt100.net/docs/vt220-rm/table2-14.html
  */
-CHARSETS['H'] =
-CHARSETS['7'] = {
+CHARSETS['H'] = CHARSETS['7'] = {
   '@': 'É',
   '[': 'Ä',
   '\\': 'Ö',

src/common/input/TextDecoder.ts

@@ -148,7 +148,7 @@ export class Utf8ToUtf32 {
     let byte2: number;
     let byte3: number;
     let byte4: number;
-    let codepoint = 0;
+    let codepoint;
     let startPos = 0;
 
     // handle leftover bytes

src/common/input/WriteBuffer.test.ts

@@ -125,5 +125,86 @@ describe('WriteBuffer', () => {
       assert.deepEqual(stack, []);
       assert.deepEqual(cbStack, []);
     });
+    it('flushSync fires onWriteParsed', () => {
+      let parsed = 0;
+      wb.onWriteParsed(() => parsed++);
+      wb.write('a');
+      wb.write('b');
+      assert.equal(parsed, 0);
+      wb.flushSync();
+      assert.equal(parsed, 1);
+    });
+    it('flushSync with no pending writes does not fire onWriteParsed', () => {
+      let parsed = 0;
+      wb.onWriteParsed(() => parsed++);
+      wb.flushSync();
+      assert.equal(parsed, 0);
+    });
+    it('dispose cancels scheduled innerWrite', done => {
+      wb.write('a');
+      wb.dispose();
+      setTimeout(() => {
+        assert.deepEqual(stack, []);
+        done();
+      }, 20);
+    });
+    it('dispose does not fire onWriteParsed for pending writes', done => {
+      let parsed = 0;
+      wb.onWriteParsed(() => parsed++);
+      wb.write('a');
+      wb.dispose();
+      setTimeout(() => {
+        assert.equal(parsed, 0);
+        done();
+      }, 20);
+    });
+    it('write after dispose is a no-op', done => {
+      wb.dispose();
+      wb.write('a');
+      setTimeout(() => {
+        assert.deepEqual(stack, []);
+        done();
+      }, 20);
+    });
+    it('dispose is idempotent', done => {
+      wb.write('a');
+      wb.dispose();
+      wb.dispose();
+      setTimeout(() => {
+        assert.deepEqual(stack, []);
+        done();
+      }, 20);
+    });
+    it('async handler continuation is skipped after dispose', done => {
+      let resolve!: (value: boolean) => void;
+      const pending = new Promise<boolean>(r => { resolve = r; });
+      wb = new WriteBuffer(() => pending);
+      wb.write('a');
+      wb.dispose();
+      resolve(true);
+      setTimeout(() => {
+        assert.deepEqual(stack, []);
+        done();
+      }, 20);
+    });
+    it('handleUserInput still processes first chunk synchronously', () => {
+      wb.handleUserInput();
+      wb.write('a');
+      assert.deepEqual(stack, ['a']);
+    });
+    it('flushSync after dispose is a no-op', done => {
+      wb.write('a');
+      wb.dispose();
+      wb.flushSync();
+      setTimeout(() => {
+        assert.deepEqual(stack, []);
+        done();
+      }, 20);
+    });
+    it('writeSync after dispose is a no-op', () => {
+      wb.dispose();
+      wb.writeSync('a');
+      assert.deepEqual(stack, []);
+    });
   });
 });

src/common/input/WriteBuffer.ts

@@ -4,11 +4,10 @@
  * @license MIT
  */
 
-import { Disposable } from 'common/Lifecycle';
+import { TimeoutTimer } from 'common/Async';
+import { Disposable, toDisposable } from 'common/Lifecycle';
 import { Emitter } from 'common/Event';
 
-declare const setTimeout: (handler: () => void, timeout?: number) => void;
-
 const enum Constants {
   /**
    * Safety watermark to avoid memory exhaustion and browser engine crash on fast data input.
@@ -43,11 +42,18 @@ export class WriteBuffer extends Disposable {
   private _syncCalls = 0;
   private _didUserInput = false;
 
+  private readonly _innerWriteTimer = this._register(new TimeoutTimer());
   private readonly _onWriteParsed = this._register(new Emitter<void>());
   public readonly onWriteParsed = this._onWriteParsed.event;
 
   constructor(private _action: (data: string | Uint8Array, promiseResult?: boolean) => void | Promise<boolean>) {
     super();
+    this._register(toDisposable(() => {
+      this._writeBuffer.length = 0;
+      this._callbacks.length = 0;
+      this._pendingData = 0;
+      this._bufferOffset = 0;
+    }));
   }
 
   public handleUserInput(): void {
@@ -63,6 +69,9 @@ export class WriteBuffer extends Disposable {
    * promises to resolve.
    */
   public flushSync(): void {
+    if (this._store.isDisposed) {
+      return;
+    }
     // exit early if another sync write loop is active
     if (this._isSyncWriting) {
       return;
@@ -71,7 +80,9 @@ export class WriteBuffer extends Disposable {
 
     // Process all pending chunks synchronously
     let chunk: string | Uint8Array | undefined;
+    let didProcess = false;
     while (chunk = this._writeBuffer.shift()) {
+      didProcess = true;
       this._action(chunk);
       const cb = this._callbacks.shift();
       if (cb) cb();
@@ -84,12 +95,18 @@ export class WriteBuffer extends Disposable {
     this._callbacks.length = 0;
 
     this._isSyncWriting = false;
+    if (didProcess) {
+      this._onWriteParsed.fire();
+    }
   }
 
   /**
    * @deprecated Unreliable, to be removed soon.
    */
   public writeSync(data: string | Uint8Array, maxSubsequentCalls?: number): void {
+    if (this._store.isDisposed) {
+      return;
+    }
     // stop writeSync recursions with maxSubsequentCalls argument
     // This is dangerous to use as it will lose the current data chunk
     // and return immediately.
@@ -133,6 +150,9 @@ export class WriteBuffer extends Disposable {
   }
 
   public write(data: string | Uint8Array, callback?: () => void): void {
+    if (this._store.isDisposed) {
+      return;
+    }
     if (this._pendingData > Constants.DISCARD_WATERMARK) {
       throw new Error('write data discarded, use flow control to avoid losing data');
     }
@@ -153,7 +173,7 @@ export class WriteBuffer extends Disposable {
         return;
       }
 
-      setTimeout(() => this._innerWrite());
+      this._scheduleInnerWrite();
     }
 
     this._pendingData += data.length;
@@ -189,7 +209,17 @@ export class WriteBuffer extends Disposable {
    *
    * Note, for pure sync code `lastTime` and `promiseResult` have no meaning.
    */
+  private _scheduleInnerWrite(lastTime: number = 0, promiseResult: boolean = true): void {
+    if (this._store.isDisposed) {
+      return;
+    }
+    this._innerWriteTimer.cancelAndSet(() => this._innerWrite(lastTime, promiseResult), 0);
+  }
+
   protected _innerWrite(lastTime: number = 0, promiseResult: boolean = true): void {
+    if (this._store.isDisposed) {
+      return;
+    }
     const startTime = lastTime || performance.now();
     while (this._writeBuffer.length > this._bufferOffset) {
       const data = this._writeBuffer[this._bufferOffset];
@@ -218,9 +248,16 @@ export class WriteBuffer extends Disposable {
          * responsibility to slice hard work), but we can at least schedule a screen update as we
          * gain control.
          */
-        const continuation: (r: boolean) => void = (r: boolean) => performance.now() - startTime >= Constants.WRITE_TIMEOUT_MS
-          ? setTimeout(() => this._innerWrite(0, r))
-          : this._innerWrite(startTime, r);
+        const continuation: (r: boolean) => void = (r: boolean) => {
+          if (this._store.isDisposed) {
+            return;
+          }
+          if (performance.now() - startTime >= Constants.WRITE_TIMEOUT_MS) {
+            this._scheduleInnerWrite(0, r);
+          } else {
+            this._innerWrite(startTime, r);
+          }
+        };
 
         /**
          * Optimization considerations:
@@ -267,7 +304,7 @@ export class WriteBuffer extends Disposable {
         this._callbacks = this._callbacks.slice(this._bufferOffset);
         this._bufferOffset = 0;
       }
-      setTimeout(() => this._innerWrite());
+      this._scheduleInnerWrite();
     } else {
       this._writeBuffer.length = 0;
       this._callbacks.length = 0;

src/common/parser/ApcParser.ts

@@ -7,6 +7,7 @@ import { IApcHandler, IHandlerCollection, ApcFallbackHandlerType, IApcParser, IS
 import { ParserConstants } from 'common/parser/Constants';
 import { utf32ToString } from 'common/input/TextDecoder';
 import { IDisposable } from 'common/Types';
+import { LimitedStringBuilder } from 'common/StringBuilder';
 
 const EMPTY_HANDLERS: IApcHandler[] = [];
 
@@ -153,13 +154,13 @@ export class ApcParser implements IApcParser {
 export class ApcHandler implements IApcHandler {
   private static _payloadLimit = ParserConstants.PAYLOAD_LIMIT;
 
-  private _data = '';
+  private _data = new LimitedStringBuilder(ApcHandler._payloadLimit);
   private _hitLimit: boolean = false;
 
   constructor(private _handler: (data: string) => boolean | Promise<boolean>) { }
 
   public start(): void {
-    this._data = '';
+    this._data.reset();
     this._hitLimit = false;
   }
 
@@ -167,9 +168,7 @@ export class ApcHandler implements IApcHandler {
     if (this._hitLimit) {
       return;
     }
-    this._data += utf32ToString(data, start, end);
-    if (this._data.length > ApcHandler._payloadLimit) {
-      this._data = '';
+    if (this._data.append(utf32ToString(data, start, end))) {
       this._hitLimit = true;
     }
   }
@@ -179,18 +178,18 @@ export class ApcHandler implements IApcHandler {
     if (this._hitLimit) {
       ret = false;
     } else if (success) {
-      ret = this._handler(this._data);
+      ret = this._handler(this._data.toString());
       if (ret instanceof Promise) {
         // need to hold data until `ret` got resolved
         // dont care for errors, data will be freed anyway on next start
         return ret.then(res => {
-          this._data = '';
+          this._data.reset();
           this._hitLimit = false;
           return res;
         });
       }
     }
-    this._data = '';
+    this._data.reset();
     this._hitLimit = false;
     return ret;
   }

src/common/parser/DcsParser.ts

@@ -8,6 +8,7 @@ import { IDcsHandler, IParams, IHandlerCollection, IDcsParser, DcsFallbackHandle
 import { utf32ToString } from 'common/input/TextDecoder';
 import { Params } from 'common/parser/Params';
 import { ParserConstants } from 'common/parser/Constants';
+import { LimitedStringBuilder } from 'common/StringBuilder';
 
 const EMPTY_HANDLERS: IDcsHandler[] = [];
 
@@ -140,7 +141,7 @@ EMPTY_PARAMS.addParam(0);
 export class DcsHandler implements IDcsHandler {
   private static _payloadLimit = ParserConstants.PAYLOAD_LIMIT;
 
-  private _data = '';
+  private _data = new LimitedStringBuilder(DcsHandler._payloadLimit);
   private _params: IParams = EMPTY_PARAMS;
   private _hitLimit: boolean = false;
 
@@ -152,7 +153,7 @@ export class DcsHandler implements IDcsHandler {
     // perf optimization:
     // clone only, if we have non empty params, otherwise stick with default
     this._params = (params.length > 1 || params.params[0]) ? params.clone() : EMPTY_PARAMS;
-    this._data = '';
+    this._data.reset();
     this._hitLimit = false;
   }
 
@@ -160,9 +161,7 @@ export class DcsHandler implements IDcsHandler {
     if (this._hitLimit) {
       return;
     }
-    this._data += utf32ToString(data, start, end);
-    if (this._data.length > DcsHandler._payloadLimit) {
-      this._data = '';
+    if (this._data.append(utf32ToString(data, start, end))) {
       this._hitLimit = true;
     }
   }
@@ -172,20 +171,20 @@ export class DcsHandler implements IDcsHandler {
     if (this._hitLimit) {
       ret = false;
     } else if (success) {
-      ret = this._handler(this._data, this._params);
+      ret = this._handler(this._data.toString(), this._params);
       if (ret instanceof Promise) {
         // need to hold data and params until `ret` got resolved
         // dont care for errors, data will be freed anyway on next start
         return ret.then(res => {
           this._params = EMPTY_PARAMS;
-          this._data = '';
+          this._data.reset();
           this._hitLimit = false;
           return res;
         });
       }
     }
     this._params = EMPTY_PARAMS;
-    this._data = '';
+    this._data.reset();
     this._hitLimit = false;
     return ret;
   }

src/common/parser/EscapeSequenceParser.ts

@@ -572,8 +572,8 @@ export class EscapeSequenceParser extends Disposable implements IEscapeSequenceP
    * ```
    */
   public parse(data: Uint32Array, length: number, promiseResult?: boolean): void | Promise<boolean> {
-    let code = 0;
-    let transition = 0;
+    let code: number;
+    let transition: number;
     let start = 0;
     let handlerResult: void | boolean | Promise<boolean>;
 

src/common/parser/OscParser.ts

@@ -7,6 +7,7 @@ import { IOscHandler, IHandlerCollection, OscFallbackHandlerType, IOscParser, IS
 import { OscState, ParserConstants } from 'common/parser/Constants';
 import { utf32ToString } from 'common/input/TextDecoder';
 import { IDisposable } from 'common/Types';
+import { LimitedStringBuilder } from 'common/StringBuilder';
 
 const EMPTY_HANDLERS: IOscHandler[] = [];
 
@@ -194,13 +195,13 @@ export class OscParser implements IOscParser {
 export class OscHandler implements IOscHandler {
   private static _payloadLimit = ParserConstants.PAYLOAD_LIMIT;
 
-  private _data = '';
+  private _data = new LimitedStringBuilder(OscHandler._payloadLimit);
   private _hitLimit: boolean = false;
 
   constructor(private _handler: (data: string) => boolean | Promise<boolean>) { }
 
   public start(): void {
-    this._data = '';
+    this._data.reset();
     this._hitLimit = false;
   }
 
@@ -208,9 +209,7 @@ export class OscHandler implements IOscHandler {
     if (this._hitLimit) {
       return;
     }
-    this._data += utf32ToString(data, start, end);
-    if (this._data.length > OscHandler._payloadLimit) {
-      this._data = '';
+    if (this._data.append(utf32ToString(data, start, end))) {
       this._hitLimit = true;
     }
   }
@@ -220,18 +219,18 @@ export class OscHandler implements IOscHandler {
     if (this._hitLimit) {
       ret = false;
     } else if (success) {
-      ret = this._handler(this._data);
+      ret = this._handler(this._data.toString());
       if (ret instanceof Promise) {
         // need to hold data until `ret` got resolved
         // dont care for errors, data will be freed anyway on next start
         return ret.then(res => {
-          this._data = '';
+          this._data.reset();
           this._hitLimit = false;
           return res;
         });
       }
     }
-    this._data = '';
+    this._data.reset();
     this._hitLimit = false;
     return ret;
   }

src/common/public/BufferNamespaceApi.ts

@@ -20,7 +20,7 @@ export class BufferNamespaceApi extends Disposable implements IBufferNamespaceAp
     super();
     this._normal = new BufferApiView(this._core.buffers.normal, 'normal');
     this._alternate = new BufferApiView(this._core.buffers.alt, 'alternate');
-    this._core.buffers.onBufferActivate(() => this._onBufferChange.fire(this.active));
+    this._register(this._core.buffers.onBufferActivate(() => this._onBufferChange.fire(this.active)));
   }
   public get active(): IBufferApi {
     if (this._core.buffers.active === this._core.buffers.normal) { return this.normal; }

src/common/services/CoreService.ts

@@ -3,7 +3,6 @@
  * @license MIT
  */
 
-import { clone } from 'common/Clone';
 import { Disposable } from 'common/Lifecycle';
 import { IDecPrivateModes, IKittyKeyboardState, IModes } from 'common/Types';
 import { IBufferService, ICoreService, ILogService, IOptionsService } from 'common/services/Services';
@@ -61,14 +60,14 @@ export class CoreService extends Disposable implements ICoreService {
   ) {
     super();
     this.isCursorInitialized = _optionsService.rawOptions.showCursorImmediately ?? false;
-    this.modes = clone(DEFAULT_MODES);
-    this.decPrivateModes = clone(DEFAULT_DEC_PRIVATE_MODES);
+    this.modes = structuredClone(DEFAULT_MODES);
+    this.decPrivateModes = structuredClone(DEFAULT_DEC_PRIVATE_MODES);
     this.kittyKeyboard = DEFAULT_KITTY_KEYBOARD_STATE();
   }
 
   public reset(): void {
-    this.modes = clone(DEFAULT_MODES);
-    this.decPrivateModes = clone(DEFAULT_DEC_PRIVATE_MODES);
+    this.modes = structuredClone(DEFAULT_MODES);
+    this.decPrivateModes = structuredClone(DEFAULT_DEC_PRIVATE_MODES);
     this.kittyKeyboard = DEFAULT_KITTY_KEYBOARD_STATE();
   }
 

src/common/services/DecorationService.ts

@@ -88,12 +88,10 @@ export class DecorationService extends Disposable implements IDecorationService
     if (!bucket) {
       return;
     }
-    let xmin = 0;
-    let xmax = 0;
     for (const d of bucket) {
-      xmin = d.options.x ?? 0;
-      xmax = xmin + (d.options.width ?? 1);
-      if (x >= xmin && x < xmax && (!layer || (d.options.layer ?? 'bottom') === layer)) {
+      $xmin = d.options.x ?? 0;
+      $xmax = $xmin + (d.options.width ?? 1);
+      if (x >= $xmin && x < $xmax && (!layer || (d.options.layer ?? 'bottom') === layer)) {
         yield d;
       }
     }
@@ -225,12 +223,7 @@ export class DecorationLineCache extends Disposable {
       if (newLine < 0) {
         continue;
       }
-      const existing = newMap.get(newLine);
-      if (existing) {
-        existing.push(...bucket);
-      } else {
-        newMap.set(newLine, bucket.slice());
-      }
+      this._mergeLineBucket(newMap, newLine, bucket);
     }
     this._decorationsByLine.clear();
     for (const [line, bucket] of newMap) {
@@ -254,7 +247,9 @@ export class DecorationLineCache extends Disposable {
   private _mergeLineBucket(newMap: Map<number, IInternalDecoration[]>, line: number, bucket: IInternalDecoration[]): void {
     const existing = newMap.get(line);
     if (existing) {
-      existing.push(...bucket);
+      for (let i = 0, len = bucket.length; i < len; i++) {
+        existing.push(bucket[i]);
+      }
     } else {
       newMap.set(line, bucket.slice());
     }

src/common/services/OptionsService.ts

@@ -41,6 +41,7 @@ export const DEFAULT_OPTIONS: Readonly<Required<ITerminalOptions>> = {
   macOptionIsMeta: false,
   macOptionClickForcesSelection: false,
   minimumContrastRatio: 1,
+  mouseEventsRequireAlt: false,
   disableStdin: false,
   allowProposedApi: false,
   allowTransparency: false,

src/common/services/Services.ts

@@ -234,6 +234,7 @@ export interface ITerminalOptions {
   macOptionIsMeta?: boolean;
   macOptionClickForcesSelection?: boolean;
   minimumContrastRatio?: number;
+  mouseEventsRequireAlt?: boolean;
   reflowCursorLine?: boolean;
   rescaleOverlappingGlyphs?: boolean;
   rightClickSelectsWord?: boolean;

src/headless/Terminal.ts

@@ -69,12 +69,7 @@ export class Terminal extends CoreTerminal {
     return this.buffer.markers;
   }
 
-  public addMarker(cursorYOffset: number): IMarker | undefined {
-    // Disallow markers on the alt buffer
-    if (this.buffer !== this.buffers.normal) {
-      return;
-    }
-
+  public registerMarker(cursorYOffset: number): IMarker {
     return this.buffer.addMarker(this.buffer.ybase + this.buffer.y + cursorYOffset);
   }
 
@@ -108,6 +103,7 @@ export class Terminal extends CoreTerminal {
       // Don't clear if it's already clear
       return;
     }
+    this.buffer.clearAllMarkers();
     this.buffer.lines.set(0, this.buffer.lines.get(this.buffer.ybase + this.buffer.y)!);
     this.buffer.lines.length = 1;
     this.buffer.ydisp = 0;

src/headless/public/Terminal.test.ts

@@ -114,6 +114,29 @@ describe('Headless API Tests', function (): void {
     }
   });
 
+  it('clear disposes markers', async () => {
+    term = new Terminal({ rows: 5, allowProposedApi: true });
+    for (let i = 0; i < 10; i++) {
+      await writeSync('\n\rtest' + i);
+    }
+    const markers = [
+      term.registerMarker(1),
+      term.registerMarker(2),
+      term.registerMarker(3),
+      term.registerMarker(4)
+    ];
+    let disposeCount = 0;
+    for (const marker of markers) {
+      marker.onDispose(() => disposeCount++);
+    }
+    term.clear();
+    strictEqual(disposeCount, markers.length);
+    for (const marker of markers) {
+      strictEqual(marker.isDisposed, true);
+    }
+    strictEqual(term.markers.length, 0);
+  });
+
   describe('options', () => {
     const termOptions = {
       cols: 80,
@@ -396,6 +419,15 @@ describe('Headless API Tests', function (): void {
       strictEqual(term.buffer.normal.getLine(0)!.translateToString(), 'norm ');
       strictEqual(term.buffer.alternate.getLine(0), undefined);
     });
+
+    it('registerMarker on alternate buffer', async () => {
+      term = new Terminal({ cols: 5, allowProposedApi: true });
+      await writeSync('\x1b[?47h');
+      const marker = term.registerMarker(0);
+      strictEqual(term.buffer.active.type, 'alternate');
+      strictEqual(term.markers.length, 1);
+      strictEqual(term.markers[0], marker);
+    });
   });
 
   describe('modes', () => {

src/headless/public/Terminal.ts

@@ -40,15 +40,6 @@ export class Terminal extends Disposable implements ITerminalApi {
     };
 
     for (const propName in this._core.options) {
-      Object.defineProperty(this._publicOptions, propName, {
-        get: () => {
-          return this._core.options[propName];
-        },
-        set: (value: any) => {
-          this._checkReadonlyOptions(propName);
-          this._core.options[propName] = value;
-        }
-      });
       const desc = {
         get: getter.bind(this, propName),
         set: setter.bind(this, propName)
@@ -139,11 +130,11 @@ export class Terminal extends Disposable implements ITerminalApi {
     this._verifyIntegers(columns, rows);
     this._core.resize(columns, rows);
   }
-  public registerMarker(cursorYOffset: number = 0): IMarker | undefined {
+  public registerMarker(cursorYOffset: number = 0): IMarker {
     this._verifyIntegers(cursorYOffset);
-    return this._core.addMarker(cursorYOffset);
+    return this._core.registerMarker(cursorYOffset);
   }
-  public addMarker(cursorYOffset: number): IMarker | undefined {
+  public addMarker(cursorYOffset: number): IMarker {
     return this.registerMarker(cursorYOffset);
   }
   public dispose(): void {

src/tsconfig-library-base.json

@@ -4,7 +4,6 @@
     "composite": true,
     "strict": true,
     "declarationMap": true,
-    "experimentalDecorators": true,
-    "downlevelIteration": true
+    "experimentalDecorators": true
   }
 }

test/benchmark/tsconfig.json

@@ -8,10 +8,10 @@
     "types": [
       "../../node_modules/@types/node"
     ],
-    "moduleResolution": "node",
+    "moduleResolution": "nodenext",
     "strict": false,
     "target": "es2021",
-    "module": "commonjs",
+    "module": "nodenext",
     "paths": {
       "common/*": [ "../../src/common/*" ],
       "browser/*": [ "../../src/browser/*" ],