From fa7889cdd02436f40e1c581f135900d5fedb9f21 Mon Sep 17 00:00:00 2001
From: meganrogge <megrogge@gmail.com>
Date: Thu, 1 Apr 2021 12:17:34 -0700
Subject: [PATCH] add onRecovercontext event

---
 addons/xterm-addon-webgl/src/WebglAddon.ts    |  6 +++++-
 addons/xterm-addon-webgl/src/WebglRenderer.ts | 12 ++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/addons/xterm-addon-webgl/src/WebglAddon.ts b/addons/xterm-addon-webgl/src/WebglAddon.ts
index aef1301e..8eeda832 100644
--- a/addons/xterm-addon-webgl/src/WebglAddon.ts
+++ b/addons/xterm-addon-webgl/src/WebglAddon.ts
@@ -3,14 +3,17 @@
  * @license MIT
  */
 
-import { Terminal, ITerminalAddon } from 'xterm';
+import { Terminal, ITerminalAddon, IEvent } from 'xterm';
 import { WebglRenderer } from './WebglRenderer';
 import { IRenderService } from 'browser/services/Services';
 import { IColorSet } from 'browser/Types';
+import { EventEmitter } from 'common/EventEmitter';
 
 export class WebglAddon implements ITerminalAddon {
   private _terminal?: Terminal;
   private _renderer?: WebglRenderer;
+  private _onRecoverContext = new EventEmitter<void>();
+  public get onRecoverContext(): IEvent<void> { return this._onRecoverContext.event; }
 
   constructor(
     private _preserveDrawingBuffer?: boolean
@@ -24,6 +27,7 @@ export class WebglAddon implements ITerminalAddon {
     const renderService: IRenderService = (<any>terminal)._core._renderService;
     const colors: IColorSet = (<any>terminal)._core._colorManager.colors;
     this._renderer = new WebglRenderer(terminal, colors, this._preserveDrawingBuffer);
+    this._renderer.onRecoverContext(() => this._onRecoverContext.fire());
     renderService.setRenderer(this._renderer);
   }
 
diff --git a/addons/xterm-addon-webgl/src/WebglRenderer.ts b/addons/xterm-addon-webgl/src/WebglRenderer.ts
index fecd5742..86e2900d 100644
--- a/addons/xterm-addon-webgl/src/WebglRenderer.ts
+++ b/addons/xterm-addon-webgl/src/WebglRenderer.ts
@@ -19,6 +19,7 @@ import { IRenderDimensions, IRenderer, IRequestRedrawEvent } from 'browser/rende
 import { ITerminal, IColorSet } from 'browser/Types';
 import { EventEmitter } from 'common/EventEmitter';
 import { CellData } from 'common/buffer/CellData';
+import { addDisposableDomListener } from 'browser/Lifecycle';
 
 export class WebglRenderer extends Disposable implements IRenderer {
   private _renderLayers: IRenderLayer[];
@@ -41,6 +42,9 @@ export class WebglRenderer extends Disposable implements IRenderer {
   private _onRequestRedraw = new EventEmitter<IRequestRedrawEvent>();
   public get onRequestRedraw(): IEvent<IRequestRedrawEvent> { return this._onRequestRedraw.event; }
 
+  private _onRecoverContext = new EventEmitter<void>();
+  public get onRecoverContext(): IEvent<void> { return this._onRecoverContext.event; }
+
   constructor(
     private _terminal: Terminal,
     private _colors: IColorSet,
@@ -82,6 +86,9 @@ export class WebglRenderer extends Disposable implements IRenderer {
     if (!this._gl) {
       throw new Error('WebGL2 not supported ' + this._gl);
     }
+
+    this.register(addDisposableDomListener(this._canvas, 'webglcontextlost', (e) => { this._onContextLost(e); }));
+
     this._core.screenElement!.appendChild(this._canvas);
 
     this._rectangleRenderer = new RectangleRenderer(this._terminal, this._colors, this._gl, this.dimensions);
@@ -93,6 +100,11 @@ export class WebglRenderer extends Disposable implements IRenderer {
     this._isAttached = document.body.contains(this._core.screenElement!);
   }
 
+  private _onContextLost(e: Event): void {
+    e.preventDefault();
+    this._onRecoverContext.fire();
+  }
+
   public dispose(): void {
     for (const l of this._renderLayers) {
       l.dispose();