add onImageAdded to api

Author: anthonykim1

addons/addon-image/src/ImageAddon.ts

@@ -5,6 +5,7 @@
 
 import type { ITerminalAddon, IDisposable } from '@xterm/xterm';
 import type { ImageAddon as IImageApi } from '@xterm/addon-image';
+import { Emitter, type IEvent } from 'common/Event';
 import { IIPHandler } from './IIPHandler';
 import { ImageRenderer } from './ImageRenderer';
 import { ImageStorage, CELL_SIZE_DEFAULT } from './ImageStorage';
@@ -62,6 +63,8 @@ export class ImageAddon implements ITerminalAddon, IImageApi {
   private _disposables: IDisposable[] = [];
   private _terminal: ITerminalExt | undefined;
   private _handlers: Map<String, IResetHandler> = new Map();
+  private readonly _onImageAdded = new Emitter<void>();
+  public readonly onImageAdded: IEvent<void> = this._onImageAdded.event;
 
   constructor(opts?: Partial<IImageAddonOptions>) {
     this._opts = Object.assign({}, DEFAULT_OPTIONS, opts);
@@ -74,6 +77,7 @@ export class ImageAddon implements ITerminalAddon, IImageApi {
     }
     this._disposables.length = 0;
     this._handlers.clear();
+    this._onImageAdded.dispose();
   }
 
   private _disposeLater(...args: IDisposable[]): void {
@@ -88,6 +92,7 @@ export class ImageAddon implements ITerminalAddon, IImageApi {
     // internal data structures
     this._renderer = new ImageRenderer(terminal);
     this._storage = new ImageStorage(terminal, this._renderer, this._opts);
+    this._storage.onImageAdded = () => this._onImageAdded.fire();
 
     // enable size reports
     if (this._opts.enableSizeReports) {

addons/addon-image/src/ImageStorage.ts

@@ -124,6 +124,7 @@ export class ImageStorage implements IDisposable {
   private _pixelLimit: number = 2500000;
 
   private _viewportMetrics: { cols: number, rows: number };
+  public onImageAdded: (() => void) | undefined;
   public onImageDeleted: ((storageId: number) => void) | undefined;
 
   constructor(
@@ -336,6 +337,7 @@ export class ImageStorage implements IDisposable {
 
     // finally add the image
     this._images.set(imageId, imgSpec);
+    this.onImageAdded?.();
     return imageId;
   }
 

addons/addon-image/test/ImageAddon.test.ts

@@ -196,6 +196,18 @@ test.describe('ImageAddon', () => {
   });
 
   test.describe('image lifecycle & eviction', () => {
+    test('onImageAdded fires for each image', async () => {
+      await ctx.page.evaluate(`
+        window._imageAddedCount = 0;
+        window.imageAddon.onImageAdded(() => { window._imageAddedCount++; });
+      `);
+      await ctx.proxy.write(SIXEL_SEQ_0);
+      await pollFor(ctx.page, 'window._imageAddedCount', 1);
+      await ctx.proxy.write(SIXEL_SEQ_0);
+      await pollFor(ctx.page, 'window._imageAddedCount', 2);
+      await ctx.proxy.write(SIXEL_SEQ_0);
+      await pollFor(ctx.page, 'window._imageAddedCount', 3);
+    });
     test('delete image once scrolled off', async () => {
       await ctx.proxy.write(SIXEL_SEQ_0);
       pollFor(ctx.page, 'window.imageAddon._storage._images.size', 1);

addons/addon-image/test/KittyGraphics.test.ts

@@ -2159,6 +2159,19 @@ test.describe('Kitty Graphics Protocol', () => {
       strictEqual(await ctx.page.evaluate(`window.imageAddon._storage._images.has(${oldStorageId})`), false);
     });
   });
+
+  test.describe('onImageAdded callback', () => {
+    test('onImageAdded fires for each kitty image', async () => {
+      await ctx.page.evaluate(`
+        window._imageAddedCount = 0;
+        window.imageAddon.onImageAdded(() => { window._imageAddedCount++; });
+      `);
+      await ctx.proxy.write(`\x1b_Ga=T,f=100;${KITTY_BLACK_1X1_BASE64}\x1b\\`);
+      await pollFor(ctx.page, 'window._imageAddedCount', 1);
+      await ctx.proxy.write(`\x1b_Ga=T,f=100;${KITTY_RGB_3X1_BASE64}\x1b\\`);
+      await pollFor(ctx.page, 'window._imageAddedCount', 2);
+    });
+  });
 });
 
 /**

addons/addon-image/typings/addon-image.d.ts

@@ -3,7 +3,7 @@
  * @license MIT
  */
 
-import { Terminal, ITerminalAddon } from '@xterm/xterm';
+import { Terminal, ITerminalAddon, IEvent } from '@xterm/xterm';
 
 declare module '@xterm/addon-image' {
   export interface IImageAddonOptions {
@@ -116,6 +116,11 @@ declare module '@xterm/addon-image' {
      */
     public showPlaceholder: boolean;
 
+    /**
+     * Event fired whenever a new image is added to storage.
+     */
+    public readonly onImageAdded: IEvent<void>;
+
     /**
      * Get original image canvas at buffer position.
      */