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52 lines
1.4 KiB
JavaScript
52 lines
1.4 KiB
JavaScript
7 years ago
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define([
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'/bower_components/tweetnacl/nacl-fast.min.js',
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], function () {
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var Nacl = window.nacl;
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var Thumb = {
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dimension: 150, // thumbnails are all 150px
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};
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// create thumbnail image from metadata
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// return an img tag, or undefined if anything goes wrong
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Thumb.fromMetadata = function (metadata) {
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if (!metadata || typeof(metadata) !== 'object' || !metadata.thumbnail) { return; }
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try {
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var u8 = Nacl.util.decodeBase64(metadata.thumbnail);
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var blob = new Blob([u8], {
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type: 'image/png'
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});
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var url = URL.createObjectURL(blob);
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var img = new Image();
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img.src = url;
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img.width = Thumb.dimension;
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img.height = Thumb.dimension;
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return img;
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} catch (e) {
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console.error(e);
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return;
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}
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};
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// assumes that your canvas is square
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// nodeback returning blob
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Thumb.fromCanvas = function (canvas, cb) {
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canvas = canvas;
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var c2 = document.createElement('canvas');
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var d = Thumb.dimension;
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c2.width = d;
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c2.height = 2;
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var ctx = c2.getContext('2d');
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ctx.drawImage(canvas, 0, 0, d, d);
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c2.toBlob(function (blob) {
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cb(void 0, blob);
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});
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};
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Thumb.fromVideo = function (video, cb) {
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cb = cb; // WIP
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};
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return Thumb;
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});
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