fix: normalize model-visible images with Pi processing

src/agent/image-processing/resize.ts

@@ -0,0 +1,65 @@
+// Ported from @earendil-works/pi-coding-agent 1.1.0, dist/utils/image-resize.js (MIT).
+import path from "node:path";
+import { Worker } from "node:worker_threads";
+import {
+	IMAGE_RESIZE_WORKER_RESPONSE_TYPE,
+	resizeImageInProcess,
+	type ResizeImageWorkerResponse,
+} from "./resize-core.mjs";
+import type { ModelImageResizeOptions, ResizedImage } from "./types.ts";
+
+function isResizeImageWorkerResponse(value: unknown): value is ResizeImageWorkerResponse {
+	return value !== null && typeof value === "object" && "type" in value && value.type === IMAGE_RESIZE_WORKER_RESPONSE_TYPE;
+}
+
+async function resizeImageInWorker(workerPath: string, inputBytes: Uint8Array, mimeType: string, options?: ModelImageResizeOptions): Promise<ResizedImage | null> {
+	const worker = new Worker(workerPath);
+	try {
+		// Transfer a worker-owned copy so the caller's bytes remain intact.
+		const inputBytesForWorker = new Uint8Array(inputBytes);
+		return await new Promise((resolve, reject) => {
+			let settled = false;
+			const settle = (result: ResizedImage | null) => {
+				if (settled) return;
+				settled = true;
+				resolve(result);
+			};
+			const fail = (error: Error) => {
+				if (settled) return;
+				settled = true;
+				reject(error);
+			};
+			worker.on("message", (message: unknown) => {
+				// Ignore Node's own worker-channel messages (e.g. node --watch).
+				if (!isResizeImageWorkerResponse(message)) return;
+				if ("error" in message) fail(new Error(message.error));
+				else settle(message.result);
+			});
+			worker.once("error", fail);
+			worker.once("exit", (code) => {
+				if (!settled) fail(new Error(`Image resize worker exited with code ${code}`));
+			});
+			worker.postMessage({ inputBytes: inputBytesForWorker, mimeType, options }, [inputBytesForWorker.buffer]);
+		});
+	} finally {
+		void worker.terminate().catch(() => undefined);
+	}
+}
+
+export async function resizeImage(inputBytes: Uint8Array, mimeType: string, options?: ModelImageResizeOptions): Promise<ResizedImage | null> {
+	// Source-vs-runtime adaptation: Next bundles the TS orchestration, but traces
+	// unbundled .mjs worker/core/EXIF/Photon resources at this cwd-relative path.
+	// The packaged server's cwd is the standalone root. No Bun path is needed.
+	const workerPath = path.join(process.cwd(), "src/agent/image-processing/resize-worker.mjs");
+	try {
+		return await resizeImageInWorker(workerPath, inputBytes, mimeType, options);
+	} catch {
+		return resizeImageInProcess(inputBytes, mimeType, options);
+	}
+}
+
+export function formatDimensionNote(result: ResizedImage): string | undefined {
+	if (!result.wasResized) return undefined;
+	const scale = result.originalWidth / result.width;
+	return `[Image: original ${result.originalWidth}x${result.originalHeight}, displayed at ${result.width}x${result.height}. Multiply coordinates by ${scale.toFixed(2)} to map to original image.]`;
+}