Support fast scrolling using a modifier key

demo/client.ts

@@ -228,6 +228,7 @@ function initOptions(term: TerminalType): void {
     bellSound: null,
     bellStyle: ['none', 'sound'],
     cursorStyle: ['block', 'underline', 'bar'],
+    fastScrollModifier: ['alt', 'ctrl', 'shift'],
     fontFamily: null,
     fontWeight: ['normal', 'bold', '100', '200', '300', '400', '500', '600', '700', '800', '900'],
     fontWeightBold: ['normal', 'bold', '100', '200', '300', '400', '500', '600', '700', '800', '900'],

src/browser/Viewport.ts

@@ -7,7 +7,7 @@ import { Disposable } from 'common/Lifecycle';
 import { addDisposableDomListener } from 'browser/Lifecycle';
 import { IColorSet, IViewport } from 'browser/Types';
 import { ICharSizeService, IRenderService } from 'browser/services/Services';
-import { IBufferService } from 'common/services/Services';
+import { IBufferService, IOptionsService } from 'common/services/Services';
 
 const FALLBACK_SCROLL_BAR_WIDTH = 15;
 
@@ -37,6 +37,7 @@ export class Viewport extends Disposable implements IViewport {
     private readonly _viewportElement: HTMLElement,
     private readonly _scrollArea: HTMLElement,
     @IBufferService private readonly _bufferService: IBufferService,
+    @IOptionsService private readonly _optionsService: IOptionsService,
     @ICharSizeService private readonly _charSizeService: ICharSizeService,
     @IRenderService private readonly _renderService: IRenderService
   ) {
@@ -174,8 +175,31 @@ export class Viewport extends Disposable implements IViewport {
       return 0;
     }
 
+    const modifier = this._optionsService.options.fastScrollModifier;
+    const sensitivity = this._optionsService.options.fastScrollSensitivity;
+
+    // Multiply the scroll speed when the modifier is down
+    let multiplier = 1;
+    switch (modifier) {
+      case 'alt':
+        if (ev.altKey) {
+          multiplier = sensitivity;
+        }
+        break;
+      case 'ctrl':
+        if (ev.ctrlKey) {
+          multiplier = sensitivity;
+        }
+        break;
+      case 'shift':
+        if (ev.shiftKey) {
+          multiplier = sensitivity;
+        }
+        break;
+    }
+
     // Fallback to WheelEvent.DOM_DELTA_PIXEL
-    let amount = ev.deltaY;
+    let amount = ev.deltaY * multiplier;
     if (ev.deltaMode === WheelEvent.DOM_DELTA_LINE) {
       amount *= this._currentRowHeight;
     } else if (ev.deltaMode === WheelEvent.DOM_DELTA_PAGE) {

src/common/services/OptionsService.ts

@@ -23,6 +23,8 @@ export const DEFAULT_OPTIONS: ITerminalOptions = Object.freeze({
   bellSound:  DEFAULT_BELL_SOUND,
   bellStyle: 'none',
   drawBoldTextInBrightColors: true,
+  fastScrollModifier: 'alt',
+  fastScrollSensitivity: 5,
   fontFamily: 'courier-new, courier, monospace',
   fontSize: 15,
   fontWeight: 'normal',

src/common/services/Services.ts

@@ -149,6 +149,8 @@ export interface IPartialTerminalOptions {
   cursorStyle?: 'block' | 'underline' | 'bar';
   disableStdin?: boolean;
   drawBoldTextInBrightColors?: boolean;
+  fastScrollModifier?: 'alt' | 'ctrl' | 'shift';
+  fastScrollSensitivity?: number;
   fontSize?: number;
   fontFamily?: string;
   fontWeight?: FontWeight;
@@ -178,6 +180,8 @@ export interface ITerminalOptions {
   cursorStyle: 'block' | 'underline' | 'bar';
   disableStdin: boolean;
   drawBoldTextInBrightColors: boolean;
+  fastScrollModifier: 'alt' | 'ctrl' | 'shift';
+  fastScrollSensitivity: number;
   fontSize: number;
   fontFamily: string;
   fontWeight: FontWeight;

typings/xterm.d.ts

@@ -82,6 +82,16 @@ declare module 'xterm' {
      */
     drawBoldTextInBrightColors?: boolean;
 
+    /**
+     * The modifier key hold to multiply scroll speed.
+     */
+    fastScrollModifier?: 'alt' | 'ctrl' | 'shift';
+
+    /**
+     * The scroll speed multiplier used for fast scrolling.
+     */
+    fastScrollSensitivity?: number;
+
     /**
      * The font size used to render text.
      */