66 lines
1.7 KiB
JavaScript
66 lines
1.7 KiB
JavaScript
import * as html from "./html.js";
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import * as conf from "./conf.js";
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const cache = {};
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const MIME = "image/jpeg";
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const STORAGE_PREFIX = `art-${conf.artSize}` ;
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function store(key, data) {
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localStorage.setItem(`${STORAGE_PREFIX}-${key}`, data);
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}
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function load(key) {
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return localStorage.getItem(`${STORAGE_PREFIX}-${key}`);
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}
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async function bytesToImage(bytes) {
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const blob = new Blob([bytes]);
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const src = URL.createObjectURL(blob);
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const image = html.node("img", {src});
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return new Promise(resolve => {
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image.onload = () => resolve(image);
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});
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}
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function resize(image) {
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while (Math.min(image.width, image.height) >= 2*conf.artSize) {
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let tmp = html.node("canvas", {width:image.width/2, height:image.height/2});
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tmp.getContext("2d").drawImage(image, 0, 0, tmp.width, tmp.height);
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image = tmp;
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}
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const canvas = html.node("canvas", {width:conf.artSize, height:conf.artSize});
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canvas.getContext("2d").drawImage(image, 0, 0, canvas.width, canvas.height);
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return canvas;
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}
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export async function get(mpd, artist, album, songUrl = null) {
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const key = `${artist}-${album}`;
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if (key in cache) { return cache[key]; }
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const loaded = await load(key);
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if (loaded) {
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cache[key] = loaded;
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return loaded;
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}
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if (!songUrl) { return null; }
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// promise to be returned in the meantime
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let resolve;
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const promise = new Promise(res => resolve = res);
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cache[key] = promise;
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const data = await mpd.albumArt(songUrl);
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if (data) {
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const bytes = new Uint8Array(data);
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const image = await bytesToImage(bytes);
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const url = resize(image).toDataURL(MIME);
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store(key, url);
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cache[key] = url;
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resolve(url);
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} else {
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cache[key] = null;
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}
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return cache[key];
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}
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