extend AttributeData with eAttrs, implement SGR 4 subparams, tests

src/InputHandler.ts

@@ -497,7 +497,7 @@ export class InputHandler extends Disposable implements IInputHandler {
 
     // handle wide chars: reset start_cell-1 if we would overwrite the second cell of a wide char
     if (buffer.x && end - start > 0 && bufferRow.getWidth(buffer.x - 1) === 2) {
-      bufferRow.setCellFromCodePoint(buffer.x - 1, 0, 1, curAttr.fg, curAttr.bg);
+      bufferRow.setCellFromCodePoint(buffer.x - 1, 0, 1, curAttr.fg, curAttr.bg, curAttr.extended);
     }
 
     for (let pos = start; pos < end; ++pos) {
@@ -577,12 +577,12 @@ export class InputHandler extends Disposable implements IInputHandler {
         // a halfwidth char any fullwidth shifted there is lost
         // and will be set to empty cell
         if (bufferRow.getWidth(cols - 1) === 2) {
-          bufferRow.setCellFromCodePoint(cols - 1, NULL_CELL_CODE, NULL_CELL_WIDTH, curAttr.fg, curAttr.bg);
+          bufferRow.setCellFromCodePoint(cols - 1, NULL_CELL_CODE, NULL_CELL_WIDTH, curAttr.fg, curAttr.bg, curAttr.extended);
         }
       }
 
       // write current char to buffer and advance cursor
-      bufferRow.setCellFromCodePoint(buffer.x++, code, chWidth, curAttr.fg, curAttr.bg);
+      bufferRow.setCellFromCodePoint(buffer.x++, code, chWidth, curAttr.fg, curAttr.bg, curAttr.extended);
 
       // fullwidth char - also set next cell to placeholder stub and advance cursor
       // for graphemes bigger than fullwidth we can simply loop to zero
@@ -590,7 +590,7 @@ export class InputHandler extends Disposable implements IInputHandler {
       if (chWidth > 0) {
         while (--chWidth) {
           // other than a regular empty cell a cell following a wide char has no width
-          bufferRow.setCellFromCodePoint(buffer.x++, 0, 0, curAttr.fg, curAttr.bg);
+          bufferRow.setCellFromCodePoint(buffer.x++, 0, 0, curAttr.fg, curAttr.bg, curAttr.extended);
         }
       }
     }
@@ -611,7 +611,7 @@ export class InputHandler extends Disposable implements IInputHandler {
 
     // handle wide chars: reset cell to the right if it is second cell of a wide char
     if (buffer.x < cols && end - start > 0 && bufferRow.getWidth(buffer.x) === 0 && !bufferRow.hasContent(buffer.x)) {
-      bufferRow.setCellFromCodePoint(buffer.x, 0, 1, curAttr.fg, curAttr.bg);
+      bufferRow.setCellFromCodePoint(buffer.x, 0, 1, curAttr.fg, curAttr.bg, curAttr.extended);
     }
 
     this._dirtyRowService.markDirty(buffer.y);
@@ -2098,6 +2098,40 @@ export class InputHandler extends Disposable implements IInputHandler {
     return advance;
   }
 
+  /**
+   * SGR 4 subparams:
+   *    4:0   -   equal to SGR 24 (turn off all underline)
+   *    4:1   -   equal to SGR 4 (single underline)
+   *    4:2   -   equal to SGR 21 (double underline)
+   *    4:3   -   curly underline
+   *    4:4   -   dotted underline
+   *    4:5   -   dashed underline
+   */
+  private _processUnderline(subparams: Int32Array, attr: IAttributeData): void {
+    // treat extended attrs as immutable, thus always clone from old one
+    // this is needed since the buffer only holds references to it
+    attr.extended = attr.extended.clone();
+    let style = subparams[0];
+
+    // default to 1 == single underline
+    if (!~style || style > 5) {
+      style = 1;
+    }
+    attr.extended.underlineStyle = style;
+
+    // 0 deactivates underline
+    if (style === 0) {
+      attr.fg &= ~FgFlags.UNDERLINE;
+    }
+
+    // update HAS_EXTENDED in BG
+    if (attr.extended.isEmpty()) {
+      attr.bg &= ~BgFlags.HAS_EXTENDED;
+    } else {
+      attr.bg |= BgFlags.HAS_EXTENDED;
+    }
+  }
+
   /**
    * CSI Pm m  Character Attributes (SGR).
    *
@@ -2210,6 +2244,9 @@ export class InputHandler extends Disposable implements IInputHandler {
       } else if (p === 4) {
         // underlined text
         attr.fg |= FgFlags.UNDERLINE;
+        if (params.hasSubParams(i)) {
+          this._processUnderline(params.getSubParams(i), attr);
+        }
       } else if (p === 5) {
         // blink
         attr.fg |= FgFlags.BLINK;

src/common/Types.d.ts

@@ -68,10 +68,18 @@ export interface ICharset {
 export type CharData = [number, string, number, number];
 export type IColorRGB = [number, number, number];
 
+export interface IExtendedAttrs {
+  underlineStyle: number;
+  underlineColor: number;
+  clone(): IExtendedAttrs;
+  isEmpty(): boolean;
+}
+
 /** Attribute data */
 export interface IAttributeData {
   fg: number;
   bg: number;
+  extended: IExtendedAttrs;
 
   clone(): IAttributeData;
 
@@ -98,6 +106,11 @@ export interface IAttributeData {
   // colors
   getFgColor(): number;
   getBgColor(): number;
+
+  // extended attrs
+  hasExtendedAttrs(): number;
+  getUnderlineColor(): number;
+  getUnderlineStyle(): number;
 }
 
 /** Cell data */
@@ -122,7 +135,7 @@ export interface IBufferLine {
   set(index: number, value: CharData): void;
   loadCell(index: number, cell: ICellData): ICellData;
   setCell(index: number, cell: ICellData): void;
-  setCellFromCodePoint(index: number, codePoint: number, width: number, fg: number, bg: number): void;
+  setCellFromCodePoint(index: number, codePoint: number, width: number, fg: number, bg: number, eAttrs: IExtendedAttrs): void;
   addCodepointToCell(index: number, codePoint: number): void;
   insertCells(pos: number, n: number, ch: ICellData, eraseAttr?: IAttributeData): void;
   deleteCells(pos: number, n: number, fill: ICellData, eraseAttr?: IAttributeData): void;

src/common/buffer/AttributeData.ts

@@ -3,8 +3,8 @@
  * @license MIT
  */
 
-import { IAttributeData, IColorRGB } from 'common/Types';
-import { Attributes, FgFlags, BgFlags } from 'common/buffer/Constants';
+import { IAttributeData, IColorRGB, IExtendedAttrs } from 'common/Types';
+import { Attributes, FgFlags, BgFlags, UnderlineStyle } from 'common/buffer/Constants';
 
 export class AttributeData implements IAttributeData {
   static toColorRGB(value: number): IColorRGB {
@@ -22,12 +22,14 @@ export class AttributeData implements IAttributeData {
     const newObj = new AttributeData();
     newObj.fg = this.fg;
     newObj.bg = this.bg;
+    newObj.extended = this.extended.clone();
     return newObj;
   }
 
   // data
-  public fg: number = 0;
-  public bg: number = 0;
+  public fg = 0;
+  public bg = 0;
+  public extended = new ExtendedAttrs();
 
   // flags
   public isInverse(): number   { return this.fg & FgFlags.INVERSE; }
@@ -66,4 +68,47 @@ export class AttributeData implements IAttributeData {
       default:                  return -1;  // CM_DEFAULT defaults to -1
     }
   }
+
+  // extended attrs
+  public hasExtendedAttrs(): number {
+    return this.bg & BgFlags.HAS_EXTENDED;
+  }
+  public getUnderlineColor(): number {
+    if ((this.bg & BgFlags.HAS_EXTENDED) && ~this.extended.underlineColor) {
+      return this.extended.underlineColor;
+    }
+    return this.getFgColor();
+  }
+  public getUnderlineStyle(): UnderlineStyle {
+    return this.fg & FgFlags.UNDERLINE
+      ? (this.bg & BgFlags.HAS_EXTENDED ? this.extended.underlineStyle : UnderlineStyle.SINGLE)
+      : UnderlineStyle.NONE;
+  }
+}
+
+
+/**
+ * Extended attributes for a cell.
+ * Holds information about different underline styles and color.
+ */
+export class ExtendedAttrs implements IExtendedAttrs {
+  constructor(
+    // underline style, NONE is empty
+    public underlineStyle: UnderlineStyle = UnderlineStyle.NONE,
+    // underline color, -1 is empty (same as FG)
+    public underlineColor: number = -1
+  ) {}
+
+  public clone(): IExtendedAttrs {
+    return new ExtendedAttrs(this.underlineStyle, this.underlineColor);
+  }
+
+  /**
+   * Convenient method to indicate whether the object holds no additional information
+   * and can be removed from the global attr object.
+   */
+  public isEmpty(): boolean {
+    // needs to test for every single attribute stored
+    return !(this.underlineStyle !== UnderlineStyle.NONE || ~this.underlineColor);
+  }
 }

src/common/buffer/Buffer.ts

@@ -13,6 +13,7 @@ import { reflowLargerApplyNewLayout, reflowLargerCreateNewLayout, reflowLargerGe
 import { Marker } from 'common/buffer/Marker';
 import { IOptionsService, IBufferService } from 'common/services/Services';
 import { DEFAULT_CHARSET } from 'common/data/Charsets';
+import { ExtendedAttrs } from 'common/buffer/AttributeData';
 
 export const MAX_BUFFER_SIZE = 4294967295; // 2^32 - 1
 
@@ -60,9 +61,11 @@ export class Buffer implements IBuffer {
     if (attr) {
       this._nullCell.fg = attr.fg;
       this._nullCell.bg = attr.bg;
+      this._nullCell.extended = attr.extended;
     } else {
       this._nullCell.fg = 0;
       this._nullCell.bg = 0;
+      this._nullCell.extended = new ExtendedAttrs();
     }
     return this._nullCell;
   }
@@ -71,9 +74,11 @@ export class Buffer implements IBuffer {
     if (attr) {
       this._whitespaceCell.fg = attr.fg;
       this._whitespaceCell.bg = attr.bg;
+      this._whitespaceCell.extended = attr.extended;
     } else {
       this._whitespaceCell.fg = 0;
       this._whitespaceCell.bg = 0;
+      this._whitespaceCell.extended = new ExtendedAttrs();
     }
     return this._whitespaceCell;
   }

src/common/buffer/BufferLine.test.ts

@@ -2,11 +2,13 @@
  * Copyright (c) 2018 The xterm.js authors. All rights reserved.
  * @license MIT
  */
-import * as chai from 'chai';
-import { NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE, DEFAULT_ATTR, Content } from 'common/buffer/Constants';
+import { NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE, DEFAULT_ATTR, Content, UnderlineStyle, BgFlags, Attributes, FgFlags } from 'common/buffer/Constants';
 import { BufferLine } from 'common/buffer//BufferLine';
 import { CellData } from 'common/buffer/CellData';
 import { CharData, IBufferLine } from '../Types';
+import { assert, expect } from 'chai';
+import { AttributeData } from 'common/buffer/AttributeData';
+
 
 class TestBufferLine extends BufferLine {
   public get combined(): {[index: number]: string} {
@@ -22,49 +24,98 @@ class TestBufferLine extends BufferLine {
   }
 }
 
+describe('AttributeData', () => {
+  describe('extended attributes', () => {
+    it('hasExtendedAttrs', () => {
+      const attrs = new AttributeData();
+      assert.equal(!!attrs.hasExtendedAttrs(), false);
+      attrs.bg |= BgFlags.HAS_EXTENDED;
+      assert.equal(!!attrs.hasExtendedAttrs(), true);
+    });
+    it('getUnderlineColor', () => {
+      const attrs = new AttributeData();
+      attrs.extended.underlineColor = (1 << 16) | (2 << 8) | 3;
+
+      // should use FG color if BgFlags.HAS_EXTENDED is not set
+      assert.equal(attrs.getUnderlineColor(), -1);
+
+      // should use underlineColor if BgFlags.HAS_EXTENDED is set and underlineColor holds a value
+      attrs.bg |= BgFlags.HAS_EXTENDED;
+      assert.equal(attrs.getUnderlineColor(), (1 << 16) | (2 << 8) | 3);
+
+      // should use FG color if underlineColor holds no value
+      attrs.extended.underlineColor = -1;
+      attrs.fg |= Attributes.CM_P256 | 123;
+      assert.equal(attrs.getUnderlineColor(), 123);
+    });
+    it('getUnderlineStyle', () => {
+      const attrs = new AttributeData();
+
+      // defaults to no underline style
+      assert.equal(attrs.getUnderlineStyle(), UnderlineStyle.NONE);
+
+      // should return NONE if UNDERLINE is not set
+      attrs.extended.underlineStyle = UnderlineStyle.CURLY;
+      assert.equal(attrs.getUnderlineStyle(), UnderlineStyle.NONE);
+
+      // should return SINGLE style if UNDERLINE is set and HAS_EXTENDED is false
+      attrs.fg |= FgFlags.UNDERLINE;
+      assert.equal(attrs.getUnderlineStyle(), UnderlineStyle.SINGLE);
+
+      // should return correct style if both is set
+      attrs.bg |= BgFlags.HAS_EXTENDED;
+      assert.equal(attrs.getUnderlineStyle(), UnderlineStyle.CURLY);
+
+      // should return NONE if UNDERLINE is not set, but HAS_EXTENDED is true
+      attrs.fg &= ~FgFlags.UNDERLINE;
+      assert.equal(attrs.getUnderlineStyle(), UnderlineStyle.NONE);
+    });
+  });
+});
+
 describe('CellData', () => {
   it('CharData <--> CellData equality', () => {
     const cell = new CellData();
     // ASCII
     cell.setFromCharData([123, 'a', 1, 'a'.charCodeAt(0)]);
-    chai.assert.deepEqual(cell.getAsCharData(), [123, 'a', 1, 'a'.charCodeAt(0)]);
-    chai.assert.equal(cell.isCombined(), 0);
+    assert.deepEqual(cell.getAsCharData(), [123, 'a', 1, 'a'.charCodeAt(0)]);
+    assert.equal(cell.isCombined(), 0);
     // combining
     cell.setFromCharData([123, 'e\u0301', 1, '\u0301'.charCodeAt(0)]);
-    chai.assert.deepEqual(cell.getAsCharData(), [123, 'e\u0301', 1, '\u0301'.charCodeAt(0)]);
-    chai.assert.equal(cell.isCombined(), Content.IS_COMBINED_MASK);
+    assert.deepEqual(cell.getAsCharData(), [123, 'e\u0301', 1, '\u0301'.charCodeAt(0)]);
+    assert.equal(cell.isCombined(), Content.IS_COMBINED_MASK);
     // surrogate
     cell.setFromCharData([123, '𝄞', 1, 0x1D11E]);
-    chai.assert.deepEqual(cell.getAsCharData(), [123, '𝄞', 1, 0x1D11E]);
-    chai.assert.equal(cell.isCombined(), 0);
+    assert.deepEqual(cell.getAsCharData(), [123, '𝄞', 1, 0x1D11E]);
+    assert.equal(cell.isCombined(), 0);
     // surrogate + combining
     cell.setFromCharData([123, '𓂀\u0301', 1, '𓂀\u0301'.charCodeAt(2)]);
-    chai.assert.deepEqual(cell.getAsCharData(), [123, '𓂀\u0301', 1, '𓂀\u0301'.charCodeAt(2)]);
-    chai.assert.equal(cell.isCombined(), Content.IS_COMBINED_MASK);
+    assert.deepEqual(cell.getAsCharData(), [123, '𓂀\u0301', 1, '𓂀\u0301'.charCodeAt(2)]);
+    assert.equal(cell.isCombined(), Content.IS_COMBINED_MASK);
     // wide char
     cell.setFromCharData([123, '１', 2, '１'.charCodeAt(0)]);
-    chai.assert.deepEqual(cell.getAsCharData(), [123, '１', 2, '１'.charCodeAt(0)]);
-    chai.assert.equal(cell.isCombined(), 0);
+    assert.deepEqual(cell.getAsCharData(), [123, '１', 2, '１'.charCodeAt(0)]);
+    assert.equal(cell.isCombined(), 0);
   });
 });
 
 describe('BufferLine', function(): void {
   it('ctor', function(): void {
     let line: IBufferLine = new TestBufferLine(0);
-    chai.expect(line.length).equals(0);
-    chai.expect(line.isWrapped).equals(false);
+    expect(line.length).equals(0);
+    expect(line.isWrapped).equals(false);
     line = new TestBufferLine(10);
-    chai.expect(line.length).equals(10);
-    chai.expect(line.loadCell(0, new CellData()).getAsCharData()).eql([0, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE]);
-    chai.expect(line.isWrapped).equals(false);
+    expect(line.length).equals(10);
+    expect(line.loadCell(0, new CellData()).getAsCharData()).eql([0, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE]);
+    expect(line.isWrapped).equals(false);
     line = new TestBufferLine(10, undefined, true);
-    chai.expect(line.length).equals(10);
-    chai.expect(line.loadCell(0, new CellData()).getAsCharData()).eql([0, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE]);
-    chai.expect(line.isWrapped).equals(true);
+    expect(line.length).equals(10);
+    expect(line.loadCell(0, new CellData()).getAsCharData()).eql([0, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE]);
+    expect(line.isWrapped).equals(true);
     line = new TestBufferLine(10, CellData.fromCharData([123, 'a', 456, 'a'.charCodeAt(0)]), true);
-    chai.expect(line.length).equals(10);
-    chai.expect(line.loadCell(0, new CellData()).getAsCharData()).eql([123, 'a', 456, 'a'.charCodeAt(0)]);
-    chai.expect(line.isWrapped).equals(true);
+    expect(line.length).equals(10);
+    expect(line.loadCell(0, new CellData()).getAsCharData()).eql([123, 'a', 456, 'a'.charCodeAt(0)]);
+    expect(line.isWrapped).equals(true);
   });
   it('insertCells', function(): void {
     const line = new TestBufferLine(3);
@@ -72,7 +123,7 @@ describe('BufferLine', function(): void {
     line.setCell(1, CellData.fromCharData([2, 'b', 0, 'b'.charCodeAt(0)]));
     line.setCell(2, CellData.fromCharData([3, 'c', 0, 'c'.charCodeAt(0)]));
     line.insertCells(1, 3, CellData.fromCharData([4, 'd', 0, 'd'.charCodeAt(0)]));
-    chai.expect(line.toArray()).eql([
+    expect(line.toArray()).eql([
       [1, 'a', 0, 'a'.charCodeAt(0)],
       [4, 'd', 0, 'd'.charCodeAt(0)],
       [4, 'd', 0, 'd'.charCodeAt(0)]
@@ -86,7 +137,7 @@ describe('BufferLine', function(): void {
     line.setCell(3, CellData.fromCharData([4, 'd', 0, 'd'.charCodeAt(0)]));
     line.setCell(4, CellData.fromCharData([5, 'e', 0, 'e'.charCodeAt(0)]));
     line.deleteCells(1, 2, CellData.fromCharData([6, 'f', 0, 'f'.charCodeAt(0)]));
-    chai.expect(line.toArray()).eql([
+    expect(line.toArray()).eql([
       [1, 'a', 0, 'a'.charCodeAt(0)],
       [4, 'd', 0, 'd'.charCodeAt(0)],
       [5, 'e', 0, 'e'.charCodeAt(0)],
@@ -102,7 +153,7 @@ describe('BufferLine', function(): void {
     line.setCell(3, CellData.fromCharData([4, 'd', 0, 'd'.charCodeAt(0)]));
     line.setCell(4, CellData.fromCharData([5, 'e', 0, 'e'.charCodeAt(0)]));
     line.replaceCells(2, 4, CellData.fromCharData([6, 'f', 0, 'f'.charCodeAt(0)]));
-    chai.expect(line.toArray()).eql([
+    expect(line.toArray()).eql([
       [1, 'a', 0, 'a'.charCodeAt(0)],
       [2, 'b', 0, 'b'.charCodeAt(0)],
       [6, 'f', 0, 'f'.charCodeAt(0)],
@@ -118,7 +169,7 @@ describe('BufferLine', function(): void {
     line.setCell(3, CellData.fromCharData([4, 'd', 0, 'd'.charCodeAt(0)]));
     line.setCell(4, CellData.fromCharData([5, 'e', 0, 'e'.charCodeAt(0)]));
     line.fill(CellData.fromCharData([123, 'z', 0, 'z'.charCodeAt(0)]));
-    chai.expect(line.toArray()).eql([
+    expect(line.toArray()).eql([
       [123, 'z', 0, 'z'.charCodeAt(0)],
       [123, 'z', 0, 'z'.charCodeAt(0)],
       [123, 'z', 0, 'z'.charCodeAt(0)],
@@ -134,9 +185,9 @@ describe('BufferLine', function(): void {
     line.setCell(3, CellData.fromCharData([4, 'd', 0, 'd'.charCodeAt(0)]));
     line.setCell(4, CellData.fromCharData([5, 'e', 0, 'e'.charCodeAt(0)]));
     const line2 = line.clone();
-    chai.expect(TestBufferLine.prototype.toArray.apply(line2)).eql(line.toArray());
-    chai.expect(line2.length).equals(line.length);
-    chai.expect(line2.isWrapped).equals(line.isWrapped);
+    expect(TestBufferLine.prototype.toArray.apply(line2)).eql(line.toArray());
+    expect(line2.length).equals(line.length);
+    expect(line2.isWrapped).equals(line.isWrapped);
   });
   it('copyFrom', function(): void {
     const line = new TestBufferLine(5);
@@ -147,92 +198,92 @@ describe('BufferLine', function(): void {
     line.setCell(4, CellData.fromCharData([5, 'e', 0, 'e'.charCodeAt(0)]));
     const line2 = new TestBufferLine(5, CellData.fromCharData([1, 'a', 0, 'a'.charCodeAt(0)]), true);
     line2.copyFrom(line);
-    chai.expect(line2.toArray()).eql(line.toArray());
-    chai.expect(line2.length).equals(line.length);
-    chai.expect(line2.isWrapped).equals(line.isWrapped);
+    expect(line2.toArray()).eql(line.toArray());
+    expect(line2.length).equals(line.length);
+    expect(line2.isWrapped).equals(line.isWrapped);
   });
   it('should support combining chars', function(): void {
     // CHAR_DATA_CODE_INDEX resembles current behavior in InputHandler.print
     // --> set code to the last charCodeAt value of the string
     // Note: needs to be fixed once the string pointer is in place
     const line = new TestBufferLine(2, CellData.fromCharData([1, 'e\u0301', 0, '\u0301'.charCodeAt(0)]));
-    chai.expect(line.toArray()).eql([[1, 'e\u0301', 0, '\u0301'.charCodeAt(0)], [1, 'e\u0301', 0, '\u0301'.charCodeAt(0)]]);
+    expect(line.toArray()).eql([[1, 'e\u0301', 0, '\u0301'.charCodeAt(0)], [1, 'e\u0301', 0, '\u0301'.charCodeAt(0)]]);
     const line2 = new TestBufferLine(5, CellData.fromCharData([1, 'a', 0, '\u0301'.charCodeAt(0)]), true);
     line2.copyFrom(line);
-    chai.expect(line2.toArray()).eql(line.toArray());
+    expect(line2.toArray()).eql(line.toArray());
     const line3 = line.clone();
-    chai.expect(TestBufferLine.prototype.toArray.apply(line3)).eql(line.toArray());
+    expect(TestBufferLine.prototype.toArray.apply(line3)).eql(line.toArray());
   });
   describe('resize', function(): void {
     it('enlarge(false)', function(): void {
       const line = new TestBufferLine(5, CellData.fromCharData([1, 'a', 0, 'a'.charCodeAt(0)]), false);
       line.resize(10, CellData.fromCharData([1, 'a', 0, 'a'.charCodeAt(0)]));
-      chai.expect(line.toArray()).eql((Array(10) as any).fill([1, 'a', 0, 'a'.charCodeAt(0)]));
+      expect(line.toArray()).eql((Array(10) as any).fill([1, 'a', 0, 'a'.charCodeAt(0)]));
     });
     it('enlarge(true)', function(): void {
       const line = new TestBufferLine(5, CellData.fromCharData([1, 'a', 0, 'a'.charCodeAt(0)]), false);
       line.resize(10, CellData.fromCharData([1, 'a', 0, 'a'.charCodeAt(0)]));
-      chai.expect(line.toArray()).eql((Array(10) as any).fill([1, 'a', 0, 'a'.charCodeAt(0)]));
+      expect(line.toArray()).eql((Array(10) as any).fill([1, 'a', 0, 'a'.charCodeAt(0)]));
     });
     it('shrink(true) - should apply new size', function(): void {
       const line = new TestBufferLine(10, CellData.fromCharData([1, 'a', 0, 'a'.charCodeAt(0)]), false);
       line.resize(5, CellData.fromCharData([1, 'a', 0, 'a'.charCodeAt(0)]));
-      chai.expect(line.toArray()).eql((Array(5) as any).fill([1, 'a', 0, 'a'.charCodeAt(0)]));
+      expect(line.toArray()).eql((Array(5) as any).fill([1, 'a', 0, 'a'.charCodeAt(0)]));
     });
     it('shrink to 0 length', function(): void {
       const line = new TestBufferLine(10, CellData.fromCharData([1, 'a', 0, 'a'.charCodeAt(0)]), false);
       line.resize(0, CellData.fromCharData([1, 'a', 0, 'a'.charCodeAt(0)]));
-      chai.expect(line.toArray()).eql((Array(0) as any).fill([1, 'a', 0, 'a'.charCodeAt(0)]));
+      expect(line.toArray()).eql((Array(0) as any).fill([1, 'a', 0, 'a'.charCodeAt(0)]));
     });
     it('should remove combining data on replaced cells after shrinking then enlarging', () => {
       const line = new TestBufferLine(10, CellData.fromCharData([1, 'a', 0, 'a'.charCodeAt(0)]), false);
       line.set(2, [ 0, '😁', 1, '😁'.charCodeAt(0) ]);
       line.set(9, [ 0, '😁', 1, '😁'.charCodeAt(0) ]);
-      chai.expect(line.translateToString()).eql('aa😁aaaaaa😁');
-      chai.expect(Object.keys(line.combined).length).eql(2);
+      expect(line.translateToString()).eql('aa😁aaaaaa😁');
+      expect(Object.keys(line.combined).length).eql(2);
       line.resize(5, CellData.fromCharData([1, 'a', 0, 'a'.charCodeAt(0)]));
-      chai.expect(line.translateToString()).eql('aa😁aa');
+      expect(line.translateToString()).eql('aa😁aa');
       line.resize(10, CellData.fromCharData([1, 'a', 0, 'a'.charCodeAt(0)]));
-      chai.expect(line.translateToString()).eql('aa😁aaaaaaa');
-      chai.expect(Object.keys(line.combined).length).eql(1);
+      expect(line.translateToString()).eql('aa😁aaaaaaa');
+      expect(Object.keys(line.combined).length).eql(1);
     });
   });
   describe('getTrimLength', function(): void {
     it('empty line', function(): void {
       const line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE]), false);
-      chai.expect(line.getTrimmedLength()).equal(0);
+      expect(line.getTrimmedLength()).equal(0);
     });
     it('ASCII', function(): void {
       const line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE]), false);
       line.setCell(0, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
       line.setCell(2, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
-      chai.expect(line.getTrimmedLength()).equal(3);
+      expect(line.getTrimmedLength()).equal(3);
     });
     it('surrogate', function(): void {
       const line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE]), false);
       line.setCell(0, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
       line.setCell(2, CellData.fromCharData([1, '𝄞', 1, '𝄞'.charCodeAt(0)]));
-      chai.expect(line.getTrimmedLength()).equal(3);
+      expect(line.getTrimmedLength()).equal(3);
     });
     it('combining', function(): void {
       const line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE]), false);
       line.setCell(0, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
       line.setCell(2, CellData.fromCharData([1, 'e\u0301', 1, '\u0301'.charCodeAt(0)]));
-      chai.expect(line.getTrimmedLength()).equal(3);
+      expect(line.getTrimmedLength()).equal(3);
     });
     it('fullwidth', function(): void {
       const line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE]), false);
       line.setCell(0, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
       line.setCell(2, CellData.fromCharData([1, '１', 2, '１'.charCodeAt(0)]));
       line.setCell(3, CellData.fromCharData([0, '', 0, 0]));
-      chai.expect(line.getTrimmedLength()).equal(4); // also counts null cell after fullwidth
+      expect(line.getTrimmedLength()).equal(4); // also counts null cell after fullwidth
     });
   });
   describe('translateToString with and w\'o trimming', function(): void {
     it('empty line', function(): void {
       const line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE]), false);
-      chai.expect(line.translateToString(false)).equal('          ');
-      chai.expect(line.translateToString(true)).equal('');
+      expect(line.translateToString(false)).equal('          ');
+      expect(line.translateToString(true)).equal('');
     });
     it('ASCII', function(): void {
       const line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE]), false);
@@ -240,14 +291,14 @@ describe('BufferLine', function(): void {
       line.setCell(2, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
       line.setCell(4, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
       line.setCell(5, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
-      chai.expect(line.translateToString(false)).equal('a a aa    ');
-      chai.expect(line.translateToString(true)).equal('a a aa');
-      chai.expect(line.translateToString(false, 0, 5)).equal('a a a');
-      chai.expect(line.translateToString(false, 0, 4)).equal('a a ');
-      chai.expect(line.translateToString(false, 0, 3)).equal('a a');
-      chai.expect(line.translateToString(true, 0, 5)).equal('a a a');
-      chai.expect(line.translateToString(true, 0, 4)).equal('a a ');
-      chai.expect(line.translateToString(true, 0, 3)).equal('a a');
+      expect(line.translateToString(false)).equal('a a aa    ');
+      expect(line.translateToString(true)).equal('a a aa');
+      expect(line.translateToString(false, 0, 5)).equal('a a a');
+      expect(line.translateToString(false, 0, 4)).equal('a a ');
+      expect(line.translateToString(false, 0, 3)).equal('a a');
+      expect(line.translateToString(true, 0, 5)).equal('a a a');
+      expect(line.translateToString(true, 0, 4)).equal('a a ');
+      expect(line.translateToString(true, 0, 3)).equal('a a');
 
     });
     it('surrogate', function(): void {
@@ -256,14 +307,14 @@ describe('BufferLine', function(): void {
       line.setCell(2, CellData.fromCharData([1, '𝄞', 1, '𝄞'.charCodeAt(0)]));
       line.setCell(4, CellData.fromCharData([1, '𝄞', 1, '𝄞'.charCodeAt(0)]));
       line.setCell(5, CellData.fromCharData([1, '𝄞', 1, '𝄞'.charCodeAt(0)]));
-      chai.expect(line.translateToString(false)).equal('a 𝄞 𝄞𝄞    ');
-      chai.expect(line.translateToString(true)).equal('a 𝄞 𝄞𝄞');
-      chai.expect(line.translateToString(false, 0, 5)).equal('a 𝄞 𝄞');
-      chai.expect(line.translateToString(false, 0, 4)).equal('a 𝄞 ');
-      chai.expect(line.translateToString(false, 0, 3)).equal('a 𝄞');
-      chai.expect(line.translateToString(true, 0, 5)).equal('a 𝄞 𝄞');
-      chai.expect(line.translateToString(true, 0, 4)).equal('a 𝄞 ');
-      chai.expect(line.translateToString(true, 0, 3)).equal('a 𝄞');
+      expect(line.translateToString(false)).equal('a 𝄞 𝄞𝄞    ');
+      expect(line.translateToString(true)).equal('a 𝄞 𝄞𝄞');
+      expect(line.translateToString(false, 0, 5)).equal('a 𝄞 𝄞');
+      expect(line.translateToString(false, 0, 4)).equal('a 𝄞 ');
+      expect(line.translateToString(false, 0, 3)).equal('a 𝄞');
+      expect(line.translateToString(true, 0, 5)).equal('a 𝄞 𝄞');
+      expect(line.translateToString(true, 0, 4)).equal('a 𝄞 ');
+      expect(line.translateToString(true, 0, 3)).equal('a 𝄞');
     });
     it('combining', function(): void {
       const line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE]), false);
@@ -271,14 +322,14 @@ describe('BufferLine', function(): void {
       line.setCell(2, CellData.fromCharData([1, 'e\u0301', 1, '\u0301'.charCodeAt(0)]));
       line.setCell(4, CellData.fromCharData([1, 'e\u0301', 1, '\u0301'.charCodeAt(0)]));
       line.setCell(5, CellData.fromCharData([1, 'e\u0301', 1, '\u0301'.charCodeAt(0)]));
-      chai.expect(line.translateToString(false)).equal('a e\u0301 e\u0301e\u0301    ');
-      chai.expect(line.translateToString(true)).equal('a e\u0301 e\u0301e\u0301');
-      chai.expect(line.translateToString(false, 0, 5)).equal('a e\u0301 e\u0301');
-      chai.expect(line.translateToString(false, 0, 4)).equal('a e\u0301 ');
-      chai.expect(line.translateToString(false, 0, 3)).equal('a e\u0301');
-      chai.expect(line.translateToString(true, 0, 5)).equal('a e\u0301 e\u0301');
-      chai.expect(line.translateToString(true, 0, 4)).equal('a e\u0301 ');
-      chai.expect(line.translateToString(true, 0, 3)).equal('a e\u0301');
+      expect(line.translateToString(false)).equal('a e\u0301 e\u0301e\u0301    ');
+      expect(line.translateToString(true)).equal('a e\u0301 e\u0301e\u0301');
+      expect(line.translateToString(false, 0, 5)).equal('a e\u0301 e\u0301');
+      expect(line.translateToString(false, 0, 4)).equal('a e\u0301 ');
+      expect(line.translateToString(false, 0, 3)).equal('a e\u0301');
+      expect(line.translateToString(true, 0, 5)).equal('a e\u0301 e\u0301');
+      expect(line.translateToString(true, 0, 4)).equal('a e\u0301 ');
+      expect(line.translateToString(true, 0, 3)).equal('a e\u0301');
     });
     it('fullwidth', function(): void {
       const line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE]), false);
@@ -289,20 +340,20 @@ describe('BufferLine', function(): void {
       line.setCell(6, CellData.fromCharData([0, '', 0, 0]));
       line.setCell(7, CellData.fromCharData([1, '１', 2, '１'.charCodeAt(0)]));
       line.setCell(8, CellData.fromCharData([0, '', 0, 0]));
-      chai.expect(line.translateToString(false)).equal('a １ １１ ');
-      chai.expect(line.translateToString(true)).equal('a １ １１');
-      chai.expect(line.translateToString(false, 0, 7)).equal('a １ １');
-      chai.expect(line.translateToString(false, 0, 6)).equal('a １ １');
-      chai.expect(line.translateToString(false, 0, 5)).equal('a １ ');
-      chai.expect(line.translateToString(false, 0, 4)).equal('a １');
-      chai.expect(line.translateToString(false, 0, 3)).equal('a １');
-      chai.expect(line.translateToString(false, 0, 2)).equal('a ');
-      chai.expect(line.translateToString(true, 0, 7)).equal('a １ １');
-      chai.expect(line.translateToString(true, 0, 6)).equal('a １ １');
-      chai.expect(line.translateToString(true, 0, 5)).equal('a １ ');
-      chai.expect(line.translateToString(true, 0, 4)).equal('a １');
-      chai.expect(line.translateToString(true, 0, 3)).equal('a １');
-      chai.expect(line.translateToString(true, 0, 2)).equal('a ');
+      expect(line.translateToString(false)).equal('a １ １１ ');
+      expect(line.translateToString(true)).equal('a １ １１');
+      expect(line.translateToString(false, 0, 7)).equal('a １ １');
+      expect(line.translateToString(false, 0, 6)).equal('a １ １');
+      expect(line.translateToString(false, 0, 5)).equal('a １ ');
+      expect(line.translateToString(false, 0, 4)).equal('a １');
+      expect(line.translateToString(false, 0, 3)).equal('a １');
+      expect(line.translateToString(false, 0, 2)).equal('a ');
+      expect(line.translateToString(true, 0, 7)).equal('a １ １');
+      expect(line.translateToString(true, 0, 6)).equal('a １ １');
+      expect(line.translateToString(true, 0, 5)).equal('a １ ');
+      expect(line.translateToString(true, 0, 4)).equal('a １');
+      expect(line.translateToString(true, 0, 3)).equal('a １');
+      expect(line.translateToString(true, 0, 2)).equal('a ');
     });
     it('space at end', function(): void {
       const line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE]), false);
@@ -311,21 +362,21 @@ describe('BufferLine', function(): void {
       line.setCell(4, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
       line.setCell(5, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
       line.setCell(6, CellData.fromCharData([1, ' ', 1, ' '.charCodeAt(0)]));
-      chai.expect(line.translateToString(false)).equal('a a aa    ');
-      chai.expect(line.translateToString(true)).equal('a a aa ');
+      expect(line.translateToString(false)).equal('a a aa    ');
+      expect(line.translateToString(true)).equal('a a aa ');
     });
     it('should always return some sane value', function(): void {
       // sanity check - broken line with invalid out of bound null width cells
       // this can atm happen with deleting/inserting chars in inputhandler by "breaking"
       // fullwidth pairs --> needs to be fixed after settling BufferLine impl
       const line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, 0, NULL_CELL_CODE]), false);
-      chai.expect(line.translateToString(false)).equal('          ');
-      chai.expect(line.translateToString(true)).equal('');
+      expect(line.translateToString(false)).equal('          ');
+      expect(line.translateToString(true)).equal('');
     });
     it('should work with endCol=0', () => {
       const line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, 0, NULL_CELL_CODE]), false);
       line.setCell(0, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
-      chai.expect(line.translateToString(true, 0, 0)).equal('');
+      expect(line.translateToString(true, 0, 0)).equal('');
     });
   });
   describe('addCharToCell', () => {
@@ -335,9 +386,9 @@ describe('BufferLine', function(): void {
       const cell = line.loadCell(0, new CellData());
       // chars contains single combining char
       // width is set to 1
-      chai.assert.deepEqual(cell.getAsCharData(), [DEFAULT_ATTR, '\u0301', 1, 0x0301]);
+      assert.deepEqual(cell.getAsCharData(), [DEFAULT_ATTR, '\u0301', 1, 0x0301]);
       // do not account a single combining char as combined
-      chai.assert.equal(cell.isCombined(), 0);
+      assert.equal(cell.isCombined(), 0);
     });
     it('should add char to combining string in cell', () => {
       const line = new TestBufferLine(3, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE]), false);
@@ -348,9 +399,9 @@ describe('BufferLine', function(): void {
       line.loadCell(0, cell);
       // chars contains 3 chars
       // width is set to 1
-      chai.assert.deepEqual(cell.getAsCharData(), [123, 'e\u0301\u0301', 1, 0x0301]);
+      assert.deepEqual(cell.getAsCharData(), [123, 'e\u0301\u0301', 1, 0x0301]);
       // do not account a single combining char as combined
-      chai.assert.equal(cell.isCombined(), Content.IS_COMBINED_MASK);
+      assert.equal(cell.isCombined(), Content.IS_COMBINED_MASK);
     });
     it('should create combining string on taken cell', () => {
       const line = new TestBufferLine(3, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE]), false);
@@ -361,9 +412,9 @@ describe('BufferLine', function(): void {
       line.loadCell(0, cell);
       // chars contains 2 chars
       // width is set to 1
-      chai.assert.deepEqual(cell.getAsCharData(), [123, 'e\u0301', 1, 0x0301]);
+      assert.deepEqual(cell.getAsCharData(), [123, 'e\u0301', 1, 0x0301]);
       // do not account a single combining char as combined
-      chai.assert.equal(cell.isCombined(), Content.IS_COMBINED_MASK);
+      assert.equal(cell.isCombined(), Content.IS_COMBINED_MASK);
     });
   });
   describe('correct fullwidth handling', () => {
@@ -377,83 +428,291 @@ describe('BufferLine', function(): void {
       const line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, 0, NULL_CELL_CODE]), false);
       populate(line);
       line.insertCells(9, 1, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
-      chai.assert.equal(line.translateToString(), '￥￥￥￥ a');
+      assert.equal(line.translateToString(), '￥￥￥￥ a');
       line.insertCells(8, 1, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
-      chai.assert.equal(line.translateToString(), '￥￥￥￥a ');
+      assert.equal(line.translateToString(), '￥￥￥￥a ');
       line.insertCells(1, 1, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
-      chai.assert.equal(line.translateToString(), ' a ￥￥￥a');
+      assert.equal(line.translateToString(), ' a ￥￥￥a');
     });
     it('insert - wide char at end', () => {
       const line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, 0, NULL_CELL_CODE]), false);
       populate(line);
       line.insertCells(0, 3, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
-      chai.assert.equal(line.translateToString(), 'aaa￥￥￥ ');
+      assert.equal(line.translateToString(), 'aaa￥￥￥ ');
       line.insertCells(4, 1, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
-      chai.assert.equal(line.translateToString(), 'aaa a ￥￥');
+      assert.equal(line.translateToString(), 'aaa a ￥￥');
       line.insertCells(4, 1, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
-      chai.assert.equal(line.translateToString(), 'aaa aa ￥ ');
+      assert.equal(line.translateToString(), 'aaa aa ￥ ');
     });
     it('delete', () => {
       const line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, 0, NULL_CELL_CODE]), false);
       populate(line);
       line.deleteCells(0, 1, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
-      chai.assert.equal(line.translateToString(), ' ￥￥￥￥a');
+      assert.equal(line.translateToString(), ' ￥￥￥￥a');
       line.deleteCells(5, 2, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
-      chai.assert.equal(line.translateToString(), ' ￥￥￥aaa');
+      assert.equal(line.translateToString(), ' ￥￥￥aaa');
       line.deleteCells(0, 2, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
-      chai.assert.equal(line.translateToString(), ' ￥￥aaaaa');
+      assert.equal(line.translateToString(), ' ￥￥aaaaa');
     });
     it('replace - start at 0', () => {
       let line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, 0, NULL_CELL_CODE]), false);
       populate(line);
       line.replaceCells(0, 1, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
-      chai.assert.equal(line.translateToString(), 'a ￥￥￥￥');
+      assert.equal(line.translateToString(), 'a ￥￥￥￥');
       line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, 0, NULL_CELL_CODE]), false);
       populate(line);
       line.replaceCells(0, 2, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
-      chai.assert.equal(line.translateToString(), 'aa￥￥￥￥');
+      assert.equal(line.translateToString(), 'aa￥￥￥￥');
       line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, 0, NULL_CELL_CODE]), false);
       populate(line);
       line.replaceCells(0, 3, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
-      chai.assert.equal(line.translateToString(), 'aaa ￥￥￥');
+      assert.equal(line.translateToString(), 'aaa ￥￥￥');
       line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, 0, NULL_CELL_CODE]), false);
       populate(line);
       line.replaceCells(0, 8, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
-      chai.assert.equal(line.translateToString(), 'aaaaaaaa￥');
+      assert.equal(line.translateToString(), 'aaaaaaaa￥');
       line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, 0, NULL_CELL_CODE]), false);
       populate(line);
       line.replaceCells(0, 9, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
-      chai.assert.equal(line.translateToString(), 'aaaaaaaaa ');
+      assert.equal(line.translateToString(), 'aaaaaaaaa ');
       line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, 0, NULL_CELL_CODE]), false);
       populate(line);
       line.replaceCells(0, 10, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
-      chai.assert.equal(line.translateToString(), 'aaaaaaaaaa');
+      assert.equal(line.translateToString(), 'aaaaaaaaaa');
     });
     it('replace - start at 1', () => {
       let line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, 0, NULL_CELL_CODE]), false);
       populate(line);
       line.replaceCells(1, 2, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
-      chai.assert.equal(line.translateToString(), ' a￥￥￥￥');
+      assert.equal(line.translateToString(), ' a￥￥￥￥');
       line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, 0, NULL_CELL_CODE]), false);
       populate(line);
       line.replaceCells(1, 3, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
-      chai.assert.equal(line.translateToString(), ' aa ￥￥￥');
+      assert.equal(line.translateToString(), ' aa ￥￥￥');
       line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, 0, NULL_CELL_CODE]), false);
       populate(line);
       line.replaceCells(1, 4, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
-      chai.assert.equal(line.translateToString(), ' aaa￥￥￥');
+      assert.equal(line.translateToString(), ' aaa￥￥￥');
       line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, 0, NULL_CELL_CODE]), false);
       populate(line);
       line.replaceCells(1, 8, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
-      chai.assert.equal(line.translateToString(), ' aaaaaaa￥');
+      assert.equal(line.translateToString(), ' aaaaaaa￥');
       line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, 0, NULL_CELL_CODE]), false);
       populate(line);
       line.replaceCells(1, 9, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
-      chai.assert.equal(line.translateToString(), ' aaaaaaaa ');
+      assert.equal(line.translateToString(), ' aaaaaaaa ');
       line = new TestBufferLine(10, CellData.fromCharData([DEFAULT_ATTR, NULL_CELL_CHAR, 0, NULL_CELL_CODE]), false);
       populate(line);
       line.replaceCells(1, 10, CellData.fromCharData([1, 'a', 1, 'a'.charCodeAt(0)]));
-      chai.assert.equal(line.translateToString(), ' aaaaaaaaa');
+      assert.equal(line.translateToString(), ' aaaaaaaaa');
+    });
+  });
+  describe('extended attributes', () => {
+    it('setCells', function(): void {
+      const line = new TestBufferLine(5);
+      const cell = CellData.fromCharData([1, 'a', 0, 'a'.charCodeAt(0)]);
+      // no eAttrs
+      line.setCell(0, cell);
+
+      // some underline style
+      cell.extended.underlineStyle = UnderlineStyle.CURLY;
+      cell.bg |= BgFlags.HAS_EXTENDED;
+      line.setCell(1, cell);
+
+      // same eAttr, different codepoint
+      cell.content = 65;  // 'A'
+      line.setCell(2, cell);
+
+      // different eAttr
+      cell.extended = cell.extended.clone();
+      cell.extended.underlineStyle = UnderlineStyle.DOTTED;
+      line.setCell(3, cell);
+
+      // no eAttrs again
+      cell.bg &= ~BgFlags.HAS_EXTENDED;
+      line.setCell(4, cell);
+
+      assert.deepEqual(line.toArray(), [
+        [1, 'a', 0, 'a'.charCodeAt(0)],
+        [1, 'a', 0, 'a'.charCodeAt(0)],
+        [1, 'A', 0, 'A'.charCodeAt(0)],
+        [1, 'A', 0, 'A'.charCodeAt(0)],
+        [1, 'A', 0, 'A'.charCodeAt(0)]
+      ]);
+      assert.equal((line as any)._extendedAttrs[0], undefined);
+      assert.equal((line as any)._extendedAttrs[1].underlineStyle, UnderlineStyle.CURLY);
+      assert.equal((line as any)._extendedAttrs[2].underlineStyle, UnderlineStyle.CURLY);
+      assert.equal((line as any)._extendedAttrs[3].underlineStyle, UnderlineStyle.DOTTED);
+      assert.equal((line as any)._extendedAttrs[4], undefined);
+      // should be ref to the same object
+      assert.equal((line as any)._extendedAttrs[1], (line as any)._extendedAttrs[2]);
+      // should be a different obj
+      assert.notEqual((line as any)._extendedAttrs[1], (line as any)._extendedAttrs[3]);
+    });
+    it('loadCell', () => {
+      const line = new TestBufferLine(5);
+      const cell = CellData.fromCharData([1, 'a', 0, 'a'.charCodeAt(0)]);
+      // no eAttrs
+      line.setCell(0, cell);
+
+      // some underline style
+      cell.extended.underlineStyle = UnderlineStyle.CURLY;
+      cell.bg |= BgFlags.HAS_EXTENDED;
+      line.setCell(1, cell);
+
+      // same eAttr, different codepoint
+      cell.content = 65;  // 'A'
+      line.setCell(2, cell);
+
+      // different eAttr
+      cell.extended = cell.extended.clone();
+      cell.extended.underlineStyle = UnderlineStyle.DOTTED;
+      line.setCell(3, cell);
+
+      // no eAttrs again
+      cell.bg &= ~BgFlags.HAS_EXTENDED;
+      line.setCell(4, cell);
+
+      const cell0 = new CellData();
+      line.loadCell(0, cell0);
+      const cell1 = new CellData();
+      line.loadCell(1, cell1);
+      const cell2 = new CellData();
+      line.loadCell(2, cell2);
+      const cell3 = new CellData();
+      line.loadCell(3, cell3);
+      const cell4 = new CellData();
+      line.loadCell(4, cell4);
+
+      assert.equal(cell0.extended.underlineStyle, UnderlineStyle.NONE);
+      assert.equal(cell1.extended.underlineStyle, UnderlineStyle.CURLY);
+      assert.equal(cell2.extended.underlineStyle, UnderlineStyle.CURLY);
+      assert.equal(cell3.extended.underlineStyle, UnderlineStyle.DOTTED);
+      assert.equal(cell4.extended.underlineStyle, UnderlineStyle.NONE);
+      assert.equal(cell1.extended, cell2.extended);
+      assert.notEqual(cell2.extended, cell3.extended);
+    });
+    it('fill', () => {
+      const line = new TestBufferLine(3);
+      const cell = CellData.fromCharData([1, 'a', 0, 'a'.charCodeAt(0)]);
+      cell.extended.underlineStyle = UnderlineStyle.CURLY;
+      cell.bg |= BgFlags.HAS_EXTENDED;
+      line.fill(cell);
+      assert.equal((line as any)._extendedAttrs[0].underlineStyle, UnderlineStyle.CURLY);
+      assert.equal((line as any)._extendedAttrs[1].underlineStyle, UnderlineStyle.CURLY);
+      assert.equal((line as any)._extendedAttrs[2].underlineStyle, UnderlineStyle.CURLY);
+    });
+    it('insertCells', () => {
+      const line = new TestBufferLine(5);
+      const cell = CellData.fromCharData([1, 'a', 0, 'a'.charCodeAt(0)]);
+      cell.extended.underlineStyle = UnderlineStyle.CURLY;
+      cell.bg |= BgFlags.HAS_EXTENDED;
+      line.insertCells(1, 3, cell);
+      assert.equal((line as any)._extendedAttrs[1].underlineStyle, UnderlineStyle.CURLY);
+      assert.equal((line as any)._extendedAttrs[2].underlineStyle, UnderlineStyle.CURLY);
+      assert.equal((line as any)._extendedAttrs[3].underlineStyle, UnderlineStyle.CURLY);
+      assert.equal((line as any)._extendedAttrs[4], undefined);
+      cell.extended = cell.extended.clone();
+      cell.extended.underlineStyle = UnderlineStyle.DOTTED;
+      line.insertCells(2, 2, cell);
+      assert.equal((line as any)._extendedAttrs[1].underlineStyle, UnderlineStyle.CURLY);
+      assert.equal((line as any)._extendedAttrs[2].underlineStyle, UnderlineStyle.DOTTED);
+      assert.equal((line as any)._extendedAttrs[3].underlineStyle, UnderlineStyle.DOTTED);
+      assert.equal((line as any)._extendedAttrs[4].underlineStyle, UnderlineStyle.CURLY);
+    });
+    it('deleteCells', () => {
+      const line = new TestBufferLine(5);
+      const fillCell = CellData.fromCharData([1, 'a', 0, 'a'.charCodeAt(0)]);
+      fillCell.extended.underlineStyle = UnderlineStyle.CURLY;
+      fillCell.bg |= BgFlags.HAS_EXTENDED;
+      line.fill(fillCell);
+      fillCell.extended = fillCell.extended.clone();
+      fillCell.extended.underlineStyle = UnderlineStyle.DOUBLE;
+      line.deleteCells(1, 3, fillCell);
+      assert.equal((line as any)._extendedAttrs[0].underlineStyle, UnderlineStyle.CURLY);
+      assert.equal((line as any)._extendedAttrs[1].underlineStyle, UnderlineStyle.CURLY);
+      assert.equal((line as any)._extendedAttrs[2].underlineStyle, UnderlineStyle.DOUBLE);
+      assert.equal((line as any)._extendedAttrs[3].underlineStyle, UnderlineStyle.DOUBLE);
+      assert.equal((line as any)._extendedAttrs[4].underlineStyle, UnderlineStyle.DOUBLE);
+    });
+    it('replaceCells', () => {
+      const line = new TestBufferLine(5);
+      const fillCell = CellData.fromCharData([1, 'a', 0, 'a'.charCodeAt(0)]);
+      fillCell.extended.underlineStyle = UnderlineStyle.CURLY;
+      fillCell.bg |= BgFlags.HAS_EXTENDED;
+      line.fill(fillCell);
+      fillCell.extended = fillCell.extended.clone();
+      fillCell.extended.underlineStyle = UnderlineStyle.DOUBLE;
+      line.replaceCells(1, 3, fillCell);
+      assert.equal((line as any)._extendedAttrs[0].underlineStyle, UnderlineStyle.CURLY);
+      assert.equal((line as any)._extendedAttrs[1].underlineStyle, UnderlineStyle.DOUBLE);
+      assert.equal((line as any)._extendedAttrs[2].underlineStyle, UnderlineStyle.DOUBLE);
+      assert.equal((line as any)._extendedAttrs[3].underlineStyle, UnderlineStyle.CURLY);
+      assert.equal((line as any)._extendedAttrs[4].underlineStyle, UnderlineStyle.CURLY);
+    });
+    it('clone', () => {
+      const line = new TestBufferLine(5);
+      const cell = CellData.fromCharData([1, 'a', 0, 'a'.charCodeAt(0)]);
+      // no eAttrs
+      line.setCell(0, cell);
+
+      // some underline style
+      cell.extended.underlineStyle = UnderlineStyle.CURLY;
+      cell.bg |= BgFlags.HAS_EXTENDED;
+      line.setCell(1, cell);
+
+      // same eAttr, different codepoint
+      cell.content = 65;  // 'A'
+      line.setCell(2, cell);
+
+      // different eAttr
+      cell.extended = cell.extended.clone();
+      cell.extended.underlineStyle = UnderlineStyle.DOTTED;
+      line.setCell(3, cell);
+
+      // no eAttrs again
+      cell.bg &= ~BgFlags.HAS_EXTENDED;
+      line.setCell(4, cell);
+
+      const nLine = line.clone();
+      assert.equal((nLine as any)._extendedAttrs[0], (line as any)._extendedAttrs[0]);
+      assert.equal((nLine as any)._extendedAttrs[1], (line as any)._extendedAttrs[1]);
+      assert.equal((nLine as any)._extendedAttrs[2], (line as any)._extendedAttrs[2]);
+      assert.equal((nLine as any)._extendedAttrs[3], (line as any)._extendedAttrs[3]);
+      assert.equal((nLine as any)._extendedAttrs[4], (line as any)._extendedAttrs[4]);
+    });
+    it('copyFrom', () => {
+      const initial = new TestBufferLine(5);
+      const cell = CellData.fromCharData([1, 'a', 0, 'a'.charCodeAt(0)]);
+      // no eAttrs
+      initial.setCell(0, cell);
+
+      // some underline style
+      cell.extended.underlineStyle = UnderlineStyle.CURLY;
+      cell.bg |= BgFlags.HAS_EXTENDED;
+      initial.setCell(1, cell);
+
+      // same eAttr, different codepoint
+      cell.content = 65;  // 'A'
+      initial.setCell(2, cell);
+
+      // different eAttr
+      cell.extended = cell.extended.clone();
+      cell.extended.underlineStyle = UnderlineStyle.DOTTED;
+      initial.setCell(3, cell);
+
+      // no eAttrs again
+      cell.bg &= ~BgFlags.HAS_EXTENDED;
+      initial.setCell(4, cell);
+
+      const line = new TestBufferLine(5);
+      line.fill(CellData.fromCharData([1, 'b', 0, 'b'.charCodeAt(0)]));
+      line.copyFrom(initial);
+      assert.equal((line as any)._extendedAttrs[0], (initial as any)._extendedAttrs[0]);
+      assert.equal((line as any)._extendedAttrs[1], (initial as any)._extendedAttrs[1]);
+      assert.equal((line as any)._extendedAttrs[2], (initial as any)._extendedAttrs[2]);
+      assert.equal((line as any)._extendedAttrs[3], (initial as any)._extendedAttrs[3]);
+      assert.equal((line as any)._extendedAttrs[4], (initial as any)._extendedAttrs[4]);
     });
   });
 });

src/common/buffer/BufferLine.ts

@@ -3,11 +3,11 @@
  * @license MIT
  */
 
-import { CharData, IBufferLine, ICellData, IAttributeData } from 'common/Types';
+import { CharData, IBufferLine, ICellData, IAttributeData, IExtendedAttrs } from 'common/Types';
 import { stringFromCodePoint } from 'common/input/TextDecoder';
-import { CHAR_DATA_CHAR_INDEX, CHAR_DATA_WIDTH_INDEX, CHAR_DATA_ATTR_INDEX, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE, WHITESPACE_CELL_CHAR, Content } from 'common/buffer/Constants';
+import { CHAR_DATA_CHAR_INDEX, CHAR_DATA_WIDTH_INDEX, CHAR_DATA_ATTR_INDEX, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE, WHITESPACE_CELL_CHAR, Content, BgFlags } from 'common/buffer/Constants';
 import { CellData } from 'common/buffer/CellData';
-import { AttributeData } from 'common/buffer/AttributeData';
+import { AttributeData, ExtendedAttrs } from 'common/buffer/AttributeData';
 
 /**
  * buffer memory layout:
@@ -55,6 +55,7 @@ export const DEFAULT_ATTR_DATA = Object.freeze(new AttributeData());
 export class BufferLine implements IBufferLine {
   protected _data: Uint32Array;
   protected _combined: {[index: number]: string} = {};
+  protected _extendedAttrs: {[index: number]: ExtendedAttrs} = {};
   public length: number;
 
   constructor(cols: number, fillCellData?: ICellData, public isWrapped: boolean = false) {
@@ -174,6 +175,9 @@ export class BufferLine implements IBufferLine {
     if (cell.content & Content.IS_COMBINED_MASK) {
       cell.combinedData = this._combined[index];
     }
+    if (cell.bg & BgFlags.HAS_EXTENDED) {
+      cell.extended = this._extendedAttrs[index];
+    }
     return cell;
   }
 
@@ -184,6 +188,9 @@ export class BufferLine implements IBufferLine {
     if (cell.content & Content.IS_COMBINED_MASK) {
       this._combined[index] = cell.combinedData;
     }
+    if (cell.bg & BgFlags.HAS_EXTENDED) {
+      this._extendedAttrs[index] = cell.extended;
+    }
     this._data[index * CELL_SIZE + Cell.CONTENT] = cell.content;
     this._data[index * CELL_SIZE + Cell.FG] = cell.fg;
     this._data[index * CELL_SIZE + Cell.BG] = cell.bg;
@@ -194,7 +201,10 @@ export class BufferLine implements IBufferLine {
    * Since the input handler see the incoming chars as UTF32 codepoints,
    * it gets an optimized access method.
    */
-  public setCellFromCodePoint(index: number, codePoint: number, width: number, fg: number, bg: number): void {
+  public setCellFromCodePoint(index: number, codePoint: number, width: number, fg: number, bg: number, eAttrs: IExtendedAttrs): void {
+    if (bg & BgFlags.HAS_EXTENDED) {
+      this._extendedAttrs[index] = eAttrs;
+    }
     this._data[index * CELL_SIZE + Cell.CONTENT] = codePoint | (width << Content.WIDTH_SHIFT);
     this._data[index * CELL_SIZE + Cell.FG] = fg;
     this._data[index * CELL_SIZE + Cell.BG] = bg;
@@ -233,7 +243,7 @@ export class BufferLine implements IBufferLine {
 
     // handle fullwidth at pos: reset cell one to the left if pos is second cell of a wide char
     if (pos && this.getWidth(pos - 1) === 2) {
-      this.setCellFromCodePoint(pos - 1, 0, 1, eraseAttr?.fg || 0, eraseAttr?.bg || 0);
+      this.setCellFromCodePoint(pos - 1, 0, 1, eraseAttr?.fg || 0, eraseAttr?.bg || 0, eraseAttr?.extended || new ExtendedAttrs());
     }
 
     if (n < this.length - pos) {
@@ -252,7 +262,7 @@ export class BufferLine implements IBufferLine {
 
     // handle fullwidth at line end: reset last cell if it is first cell of a wide char
     if (this.getWidth(this.length - 1) === 2) {
-      this.setCellFromCodePoint(this.length - 1, 0, 1, eraseAttr?.fg || 0, eraseAttr?.bg || 0);
+      this.setCellFromCodePoint(this.length - 1, 0, 1, eraseAttr?.fg || 0, eraseAttr?.bg || 0, eraseAttr?.extended || new ExtendedAttrs());
     }
   }
 
@@ -276,21 +286,21 @@ export class BufferLine implements IBufferLine {
     // - reset pos-1 if wide char
     // - reset pos if width==0 (previous second cell of a wide char)
     if (pos && this.getWidth(pos - 1) === 2) {
-      this.setCellFromCodePoint(pos - 1, 0, 1, eraseAttr?.fg || 0, eraseAttr?.bg || 0);
+      this.setCellFromCodePoint(pos - 1, 0, 1, eraseAttr?.fg || 0, eraseAttr?.bg || 0, eraseAttr?.extended || new ExtendedAttrs());
     }
     if (this.getWidth(pos) === 0 && !this.hasContent(pos)) {
-      this.setCellFromCodePoint(pos, 0, 1, eraseAttr?.fg || 0, eraseAttr?.bg || 0);
+      this.setCellFromCodePoint(pos, 0, 1, eraseAttr?.fg || 0, eraseAttr?.bg || 0, eraseAttr?.extended || new ExtendedAttrs());
     }
   }
 
   public replaceCells(start: number, end: number, fillCellData: ICellData, eraseAttr?: IAttributeData): void {
     // handle fullwidth at start: reset cell one to the left if start is second cell of a wide char
     if (start && this.getWidth(start - 1) === 2) {
-      this.setCellFromCodePoint(start - 1, 0, 1, eraseAttr?.fg || 0, eraseAttr?.bg || 0);
+      this.setCellFromCodePoint(start - 1, 0, 1, eraseAttr?.fg || 0, eraseAttr?.bg || 0, eraseAttr?.extended || new ExtendedAttrs());
     }
     // handle fullwidth at last cell + 1: reset to empty cell if it is second part of a wide char
     if (end < this.length && this.getWidth(end - 1) === 2) {
-      this.setCellFromCodePoint(end, 0, 1, eraseAttr?.fg || 0, eraseAttr?.bg || 0);
+      this.setCellFromCodePoint(end, 0, 1, eraseAttr?.fg || 0, eraseAttr?.bg || 0, eraseAttr?.extended || new ExtendedAttrs());
     }
 
     while (start < end  && start < this.length) {
@@ -320,7 +330,7 @@ export class BufferLine implements IBufferLine {
         const data = new Uint32Array(cols * CELL_SIZE);
         data.set(this._data.subarray(0, cols * CELL_SIZE));
         this._data = data;
-        // Remove any cut off combined data
+        // Remove any cut off combined data, FIXME: repeat this for extended attrs
         const keys = Object.keys(this._combined);
         for (let i = 0; i < keys.length; i++) {
           const key = parseInt(keys[i], 10);
@@ -339,6 +349,7 @@ export class BufferLine implements IBufferLine {
   /** fill a line with fillCharData */
   public fill(fillCellData: ICellData): void {
     this._combined = {};
+    this._extendedAttrs = {};
     for (let i = 0; i < this.length; ++i) {
       this.setCell(i, fillCellData);
     }
@@ -357,6 +368,10 @@ export class BufferLine implements IBufferLine {
     for (const el in line._combined) {
       this._combined[el] = line._combined[el];
     }
+    this._extendedAttrs = {};
+    for (const el in line._extendedAttrs) {
+      this._extendedAttrs[el] = line._extendedAttrs[el];
+    }
     this.isWrapped = line.isWrapped;
   }
 
@@ -368,6 +383,9 @@ export class BufferLine implements IBufferLine {
     for (const el in this._combined) {
       newLine._combined[el] = this._combined[el];
     }
+    for (const el in this._extendedAttrs) {
+      newLine._extendedAttrs[el] = this._extendedAttrs[el];
+    }
     newLine.isWrapped = this.isWrapped;
     return newLine;
   }
@@ -397,7 +415,7 @@ export class BufferLine implements IBufferLine {
       }
     }
 
-    // Move any combined data over as needed
+    // Move any combined data over as needed, FIXME: repeat for extended attrs
     const srcCombinedKeys = Object.keys(src._combined);
     for (let i = 0; i < srcCombinedKeys.length; i++) {
       const key = parseInt(srcCombinedKeys[i], 10);

src/common/buffer/CellData.ts

@@ -3,10 +3,10 @@
  * @license MIT
  */
 
-import { CharData, ICellData } from 'common/Types';
+import { CharData, ICellData, IExtendedAttrs } from 'common/Types';
 import { stringFromCodePoint } from 'common/input/TextDecoder';
 import { CHAR_DATA_CHAR_INDEX, CHAR_DATA_WIDTH_INDEX, CHAR_DATA_ATTR_INDEX, Content } from 'common/buffer/Constants';
-import { AttributeData } from 'common/buffer/AttributeData';
+import { AttributeData, ExtendedAttrs } from 'common/buffer/AttributeData';
 
 /**
  * CellData - represents a single Cell in the terminal buffer.
@@ -19,10 +19,11 @@ export class CellData extends AttributeData implements ICellData {
     return obj;
   }
   /** Primitives from terminal buffer. */
-  public content: number = 0;
-  public fg: number = 0;
-  public bg: number = 0;
-  public combinedData: string = '';
+  public content = 0;
+  public fg = 0;
+  public bg = 0;
+  public extended: IExtendedAttrs = new ExtendedAttrs();
+  public combinedData = '';
   /** Whether cell contains a combined string. */
   public isCombined(): number {
     return this.content & Content.IS_COMBINED_MASK;

src/common/buffer/Constants.ts

@@ -121,8 +121,18 @@ export const enum FgFlags {
 
 export const enum BgFlags {
   /**
-   * bit 27..32 (upper 4 unused)
+   * bit 27..32 (upper 3 unused)
    */
   ITALIC = 0x4000000,
-  DIM = 0x8000000
+  DIM = 0x8000000,
+  HAS_EXTENDED = 0x10000000
+}
+
+export const enum UnderlineStyle {
+  NONE = 0,
+  SINGLE = 1,
+  DOUBLE = 2,
+  CURLY = 3,
+  DOTTED = 4,
+  DASHED = 5
 }