offload raw image data to Blob for off-heap storage

addons/addon-image/src/kitty/KittyGraphicsHandler.ts

@@ -303,9 +303,9 @@ export class KittyGraphicsHandler implements IApcHandler, IResetHandler {
 
     switch (action) {
       case KittyAction.TRANSMIT:
-        return this._handleTransmit(cmd, new Uint8Array(bytes), decodeError);
+        return this._handleTransmit(cmd, bytes, decodeError);
       case KittyAction.TRANSMIT_DISPLAY:
-        return this._handleTransmitDisplay(cmd, new Uint8Array(bytes), decodeError);
+        return this._handleTransmitDisplay(cmd, bytes, decodeError);
       case KittyAction.QUERY:
         return this._handleQuery(cmd, bytes, decodeError);
       default:
@@ -329,7 +329,7 @@ export class KittyGraphicsHandler implements IApcHandler, IResetHandler {
     const id = cmd.id ?? this._nextImageId++;
     const image: IKittyImageData = {
       id,
-      data: bytes,
+      data: new Blob([bytes as BlobPart]),
       width: cmd.width ?? 0,
       height: cmd.height ?? 0,
       format: (cmd.format ?? KittyFormat.PNG) as 24 | 32 | 100,
@@ -475,8 +475,7 @@ export class KittyGraphicsHandler implements IApcHandler, IResetHandler {
    * Create ImageBitmap from already-decoded image data.
    */
   private async _createBitmap(image: IKittyImageData): Promise<ImageBitmap> {
-    let bytes = image.data;
-
+    let bytes: Uint8Array = new Uint8Array(await image.data.arrayBuffer());
 
     if (image.compression === KittyCompression.ZLIB) {
       bytes = await this._decompressZlib(bytes);

addons/addon-image/src/kitty/KittyGraphicsTypes.ts

@@ -116,8 +116,8 @@ export interface IPendingTransmission {
  */
 export interface IKittyImageData {
   id: number;
-  /** Decoded image bytes (already decoded from base64) */
-  data: Uint8Array;
+  /** Decoded image data stored as Blob (off JS heap) to avoid 2GB heap limit */
+  data: Blob;
   width: number;
   height: number;
   format: 24 | 32 | 100;

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

@@ -156,7 +156,11 @@ test.describe('Kitty Graphics Protocol', () => {
       await ctx.proxy.write(`\x1b_Ga=t,f=100,i=99;${part2}\x1b\\`);
       await timeout(100);
 
-      const storedData = await ctx.page.evaluate(`Array.from(window.imageAddon._handlers.get('kitty').images.get(99).data)`);
+      const storedData = await ctx.page.evaluate(async () => {
+        const blob = (window as any).imageAddon._handlers.get('kitty').images.get(99).data;
+        const buffer = await blob.arrayBuffer();
+        return Array.from(new Uint8Array(buffer));
+      });
       deepStrictEqual(storedData, KITTY_BLACK_1X1_BYTES);
     });