Clear selection on vertical resize

Fixes #5300

src/common/services/BufferService.ts

@@ -7,7 +7,7 @@ import { Disposable } from 'vs/base/common/lifecycle';
 import { IAttributeData, IBufferLine } from 'common/Types';
 import { BufferSet } from 'common/buffer/BufferSet';
 import { IBuffer, IBufferSet } from 'common/buffer/Types';
-import { IBufferService, IOptionsService } from 'common/services/Services';
+import { IBufferService, IOptionsService, type IBufferResizeEvent } from 'common/services/Services';
 import { Emitter } from 'vs/base/common/event';
 
 export const MINIMUM_COLS = 2; // Less than 2 can mess with wide chars
@@ -22,7 +22,7 @@ export class BufferService extends Disposable implements IBufferService {
   /** Whether the user is scrolling (locks the scroll position) */
   public isUserScrolling: boolean = false;
 
-  private readonly _onResize = this._register(new Emitter<{ cols: number, rows: number }>());
+  private readonly _onResize = this._register(new Emitter<IBufferResizeEvent>());
   public readonly onResize = this._onResize.event;
   private readonly _onScroll = this._register(new Emitter<number>());
   public readonly onScroll = this._onScroll.event;
@@ -43,12 +43,12 @@ export class BufferService extends Disposable implements IBufferService {
   }
 
   public resize(cols: number, rows: number): void {
+    const colsChanged = this.cols !== cols;
+    const rowsChanged = this.rows !== rows;
     this.cols = cols;
     this.rows = rows;
     this.buffers.resize(cols, rows);
-    // TODO: This doesn't fire when scrollback changes - add a resize event to BufferSet and forward
-    //       event
-    this._onResize.fire({ cols, rows });
+    this._onResize.fire({ cols, rows, colsChanged, rowsChanged });
   }
 
   public reset(): void {

src/common/services/Services.ts

@@ -18,7 +18,7 @@ export interface IBufferService {
   readonly buffer: IBuffer;
   readonly buffers: IBufferSet;
   isUserScrolling: boolean;
-  onResize: Event<{ cols: number, rows: number }>;
+  onResize: Event<IBufferResizeEvent>;
   onScroll: Event<number>;
   scroll(eraseAttr: IAttributeData, isWrapped?: boolean): void;
   scrollLines(disp: number, suppressScrollEvent?: boolean): void;
@@ -26,6 +26,13 @@ export interface IBufferService {
   reset(): void;
 }
 
+export interface IBufferResizeEvent {
+  cols: number;
+  rows: number;
+  colsChanged: boolean;
+  rowsChanged: boolean;
+}
+
 export const ICoreMouseService = createDecorator<ICoreMouseService>('CoreMouseService');
 export interface ICoreMouseService {
   serviceBrand: undefined;