Files
marco/app/services/image-processor.js

130 lines
3.5 KiB
JavaScript

import Service from '@ember/service';
// We use the special Vite query parameter to load this as a web worker
import Worker from '../workers/image-processor?worker';
export default class ImageProcessorService extends Service {
_worker = null;
_callbacks = new Map();
_msgId = 0;
constructor() {
super(...arguments);
this._initWorker();
}
_initWorker() {
if (!this._worker && typeof Worker !== 'undefined') {
try {
this._worker = new Worker();
this._worker.onmessage = this._handleMessage.bind(this);
this._worker.onerror = this._handleError.bind(this);
} catch (e) {
console.warn('Failed to initialize image-processor worker:', e);
}
}
}
_handleMessage(e) {
const { id, success, blob, dim, blurhash, error } = e.data;
const resolver = this._callbacks.get(id);
if (resolver) {
this._callbacks.delete(id);
if (success) {
resolver.resolve({ blob, dim, blurhash });
} else {
resolver.reject(new Error(error));
}
}
}
_handleError(error) {
console.error('Image Processor Worker Error:', error);
// Reject all pending jobs
for (const [, resolver] of this._callbacks.entries()) {
resolver.reject(new Error('Worker crashed'));
}
this._callbacks.clear();
// Restart the worker for future jobs
this._worker.terminate();
this._worker = null;
this._initWorker();
}
_getImageDimensions(file) {
return new Promise((resolve, reject) => {
const img = new Image();
const url = URL.createObjectURL(file);
img.onload = () => {
const dimensions = { width: img.width, height: img.height };
URL.revokeObjectURL(url);
resolve(dimensions);
};
img.onerror = () => {
URL.revokeObjectURL(url);
reject(new Error('Could not read image dimensions'));
};
img.src = url;
});
}
async process(file, maxDimension, quality, computeBlurhash = false) {
if (!this._worker) {
// Fallback if worker initialization failed (e.g. incredibly old browsers)
throw new Error('Image processor worker is not available.');
}
try {
// 1. Get dimensions safely on the main thread
const { width: origWidth, height: origHeight } =
await this._getImageDimensions(file);
// 2. Calculate aspect-ratio preserving dimensions
let targetWidth = origWidth;
let targetHeight = origHeight;
if (origWidth > origHeight) {
if (origWidth > maxDimension) {
targetHeight = Math.round(origHeight * (maxDimension / origWidth));
targetWidth = maxDimension;
}
} else {
if (origHeight > maxDimension) {
targetWidth = Math.round(origWidth * (maxDimension / origHeight));
targetHeight = maxDimension;
}
}
// 3. Send to worker for processing
return new Promise((resolve, reject) => {
const id = ++this._msgId;
this._callbacks.set(id, { resolve, reject });
this._worker.postMessage({
type: 'PROCESS_IMAGE',
id,
file,
targetWidth,
targetHeight,
quality,
computeBlurhash,
});
});
} catch (e) {
throw new Error(`Failed to process image: ${e.message}`);
}
}
willDestroy() {
super.willDestroy(...arguments);
if (this._worker) {
this._worker.terminate();
this._worker = null;
}
this._callbacks.clear();
}
}