101 lines
3.0 KiB
TypeScript
101 lines
3.0 KiB
TypeScript
/*
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* https://github.com/morethanwords/tweb
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* Copyright (C) 2019-2021 Eduard Kuzmenko
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* https://github.com/morethanwords/tweb/blob/master/LICENSE
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*/
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import type fastBlur from '../vendor/fastBlur';
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import addHeavyTask from './heavyQueue';
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const RADIUS = 2;
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const ITERATIONS = 2;
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const isFilterAvailable = 'filter' in (document.createElement('canvas').getContext('2d') || {});
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let requireBlurPromise: Promise<any>;
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let fastBlurFunc: typeof fastBlur;
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if(!isFilterAvailable) {
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requireBlurPromise = import('../vendor/fastBlur').then(m => {
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fastBlurFunc = m.default;
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});
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} else {
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requireBlurPromise = Promise.resolve();
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}
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function processBlurNext(img: HTMLImageElement, radius: number, iterations: number) {
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return new Promise<string>((resolve) => {
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const canvas = document.createElement('canvas');
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canvas.width = img.width;
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canvas.height = img.height;
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const ctx = canvas.getContext('2d', {alpha: false});
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if(isFilterAvailable) {
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ctx.filter = `blur(${radius}px)`;
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ctx.drawImage(img, -radius * 2, -radius * 2, canvas.width + radius * 4, canvas.height + radius * 4);
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} else {
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ctx.drawImage(img, 0, 0);
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fastBlurFunc(ctx, 0, 0, canvas.width, canvas.height, radius, iterations);
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}
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resolve(canvas.toDataURL());
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/* if(DEBUG) {
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console.log(`[blur] end, radius: ${radius}, iterations: ${iterations}, time: ${performance.now() - perf}`);
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} */
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/* canvas.toBlob(blob => {
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resolve(URL.createObjectURL(blob));
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if(DEBUG) {
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console.log(`[blur] end, radius: ${radius}, iterations: ${iterations}, time: ${performance.now() - perf}`);
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}
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}); */
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});
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}
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const blurPromises: Map<string, Promise<string>> = new Map();
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const CACHE_SIZE = 1000;
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export default function blur(dataUri: string, radius: number = RADIUS, iterations: number = ITERATIONS) {
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if(!dataUri) {
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console.error('no dataUri for blur', dataUri);
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return Promise.resolve(dataUri);
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}
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if(blurPromises.size > CACHE_SIZE) {
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blurPromises.clear();
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}
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if(blurPromises.has(dataUri)) return blurPromises.get(dataUri);
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const promise = new Promise<string>((resolve) => {
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//return resolve(dataUri);
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requireBlurPromise.then(() => {
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const img = new Image();
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img.onload = () => {
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if(isFilterAvailable) {
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processBlurNext(img, radius, iterations).then(resolve);
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} else {
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addHeavyTask({
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items: [[img, radius, iterations]],
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context: null,
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process: processBlurNext
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}, 'unshift').then(results => {
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resolve(results[0]);
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});
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}
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};
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img.src = dataUri;
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/* addHeavyTask({
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items: [[dataUri, radius, iterations]],
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context: null,
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process: processBlur
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}, 'unshift').then(results => {
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resolve(results[0]);
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}); */
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});
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});
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blurPromises.set(dataUri, promise);
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return promise;
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}
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