Add terminal.integrated.fontLigatures setting

Fixes #7541

src/vs/workbench/parts/terminal/electron-browser/media/xterm.css

@@ -3,6 +3,14 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
+.monaco-workbench .panel.integrated-terminal {
+	font-feature-settings: "liga" 0;
+}
+
+.monaco-workbench .panel.integrated-terminal.enable-ligatures {
+	font-feature-settings: "liga" 1;
+}
+
 .monaco-workbench .panel.integrated-terminal .xterm {
 	background-color: transparent!important;
 	position: relative;

src/vs/workbench/parts/terminal/electron-browser/terminal.contribution.ts

@@ -59,6 +59,11 @@ configurationRegistry.registerConfiguration({
 			'description': nls.localize('terminal.integrated.fontFamily', "Controls the font family of the terminal, this defaults to editor.fontFamily's value."),
 			'type': 'string'
 		},
+		'terminal.integrated.fontLigatures': {
+			'description': nls.localize('terminal.integrated.fontLigatures', "Controls whether font ligatures are enabled in the terminal."),
+			'type': 'boolean',
+			'default': false
+		},
 		'terminal.integrated.fontSize': {
 			'description': nls.localize('terminal.integrated.fontSize', "Controls the font size of the terminal, this defaults to editor.fontSize's value."),
 			'type': 'number',

src/vs/workbench/parts/terminal/electron-browser/terminal.ts

@@ -35,6 +35,7 @@ export interface ITerminalConfiguration {
 				osx: string[]
 			},
 			fontFamily: string,
+			fontLigatures: boolean,
 			fontSize: number,
 			lineHeight: number
 		}

src/vs/workbench/parts/terminal/electron-browser/terminalConfigHelper.ts

@@ -137,6 +137,10 @@ export class TerminalConfigHelper {
 		return this.measureFont(fontFamily, fontSize + 'px', lineHeight === 0 ? 'normal' : lineHeight + 'px');
 	}
 
+	public getFontLigaturesEnabled(): boolean {
+		return this.configurationService.getConfiguration<ITerminalConfiguration>().terminal.integrated.fontLigatures;
+	}
+
 	public getCursorBlink(): boolean {
 		let editorConfig = this.configurationService.getConfiguration<IConfiguration>();
 		return editorConfig.editor.cursorBlinking === 'blink';

src/vs/workbench/parts/terminal/electron-browser/terminalPanel.ts

@@ -201,6 +201,7 @@ export class TerminalPanel extends Panel {
 			return;
 		}
 		this.terminalInstances[this.terminalService.getActiveTerminalIndex()].setFont(this.configurationHelper.getFont());
+		DOM.toggleClass(this.parentDomElement, 'enable-ligatures', this.configurationHelper.getFontLigaturesEnabled());
 		this.layout(new Dimension(this.parentDomElement.offsetWidth, this.parentDomElement.offsetHeight));
 	}