support setting the canvas renderer (#126068)

src/vs/workbench/contrib/terminal/browser/terminalInstance.ts

@@ -532,14 +532,6 @@ export class TerminalInstance extends Disposable implements ITerminalInstance {
 		const font = this._configHelper.getFont(undefined, true);
 		const config = this._configHelper.config;
 		const editorOptions = this._configurationService.getValue<IEditorOptions>('editor');
-		let xtermRendererType: RendererType;
-		if (config.gpuAcceleration === 'auto') {
-			// Set the builtin renderer to canvas, even when webgl is being used since it's an addon
-			const suggestedRendererType = this._storageService.get(SUGGESTED_RENDERER_TYPE, StorageScope.GLOBAL);
-			xtermRendererType = suggestedRendererType === 'dom' ? 'dom' : 'canvas';
-		} else {
-			xtermRendererType = config.gpuAcceleration === 'on' ? 'canvas' : 'dom';
-		}
 
 		const xterm = new Terminal({
 			// TODO: Replace null with undefined when https://github.com/xtermjs/xterm.js/issues/3329 is resolved
@@ -563,7 +555,7 @@ export class TerminalInstance extends Disposable implements ITerminalInstance {
 			fastScrollModifier: 'alt',
 			fastScrollSensitivity: editorOptions.fastScrollSensitivity,
 			scrollSensitivity: editorOptions.mouseWheelScrollSensitivity,
-			rendererType: xtermRendererType,
+			rendererType: this._getBuiltInXtermRenderer(config.gpuAcceleration, this._storageService.get(SUGGESTED_RENDERER_TYPE, StorageScope.GLOBAL)),
 			wordSeparator: config.wordSeparators
 		});
 		this._xterm = xterm;
@@ -1442,16 +1434,25 @@ export class TerminalInstance extends Disposable implements ITerminalInstance {
 		this._safeSetOption('macOptionClickForcesSelection', config.macOptionClickForcesSelection);
 		this._safeSetOption('rightClickSelectsWord', config.rightClickBehavior === 'selectWord');
 		this._safeSetOption('wordSeparator', config.wordSeparators);
+
 		const suggestedRendererType = this._storageService.get(SUGGESTED_RENDERER_TYPE, StorageScope.GLOBAL);
 		if ((config.gpuAcceleration === 'auto' && suggestedRendererType === undefined) || config.gpuAcceleration === 'on') {
 			this._enableWebglRenderer();
 		} else {
 			this._disposeOfWebglRenderer();
-			this._safeSetOption('rendererType', (config.gpuAcceleration === 'auto' && suggestedRendererType === 'dom') ? 'dom' : (config.gpuAcceleration === 'off' ? 'dom' : 'canvas'));
+			this._safeSetOption('rendererType', this._getBuiltInXtermRenderer(config.gpuAcceleration, suggestedRendererType));
 		}
 		this._refreshEnvironmentVariableInfoWidgetState(this._processManager.environmentVariableInfo);
 	}
 
+	private _getBuiltInXtermRenderer(gpuAcceleration: string, suggestedRendererType?: string): RendererType {
+		let rendererType: RendererType = 'canvas';
+		if (gpuAcceleration === 'off' || (gpuAcceleration === 'auto' && suggestedRendererType === 'dom')) {
+			rendererType = 'dom';
+		}
+		return rendererType;
+	}
+
 	private async _enableWebglRenderer(): Promise<void> {
 		if (!this._xterm || this._webglAddon) {
 			return;

src/vs/workbench/contrib/terminal/common/terminal.ts

@@ -155,7 +155,7 @@ export interface ITerminalConfiguration {
 	altClickMovesCursor: boolean;
 	macOptionIsMeta: boolean;
 	macOptionClickForcesSelection: boolean;
-	gpuAcceleration: 'auto' | 'on' | 'off';
+	gpuAcceleration: 'auto' | 'on' | 'canvas' | 'off';
 	rightClickBehavior: 'default' | 'copyPaste' | 'paste' | 'selectWord';
 	cursorBlinking: boolean;
 	cursorStyle: string;

src/vs/workbench/contrib/terminal/common/terminalConfiguration.ts

@@ -210,11 +210,12 @@ const terminalConfiguration: IConfigurationNode = {
 		},
 		[TerminalSettingId.GpuAcceleration]: {
 			type: 'string',
-			enum: ['auto', 'on', 'off'],
+			enum: ['auto', 'on', 'off', 'canvas'],
 			markdownEnumDescriptions: [
 				localize('terminal.integrated.gpuAcceleration.auto', "Let VS Code detect which renderer will give the best experience."),
 				localize('terminal.integrated.gpuAcceleration.on', "Enable GPU acceleration within the terminal."),
-				localize('terminal.integrated.gpuAcceleration.off', "Disable GPU acceleration within the terminal.")
+				localize('terminal.integrated.gpuAcceleration.off', "Disable GPU acceleration within the terminal."),
+				localize('terminal.integrated.gpuAcceleration.canvas', "Use the fallback canvas renderer within the terminal. This uses a 2d context instead of webgl and may be better on some systems.")
 			],
 			default: 'auto',
 			description: localize('terminal.integrated.gpuAcceleration', "Controls whether the terminal will leverage the GPU to do its rendering.")