96 lines
2.5 KiB
JavaScript
96 lines
2.5 KiB
JavaScript
define(() => {
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'use strict';
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// Thanks, https://stackoverflow.com/a/23522755/1180785
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const safari = /^((?!chrome|android).)*safari/i.test(navigator.userAgent);
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return class Exporter {
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constructor() {
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this.latestSVG = null;
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this.canvas = null;
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this.context = null;
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this.indexPNG = 0;
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this.latestPNGIndex = 0;
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this.latestPNG = null;
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}
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getSVGContent(renderer) {
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return renderer.svg().outerHTML;
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}
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getSVGBlob(renderer) {
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return new Blob(
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[this.getSVGContent(renderer)],
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{type: 'image/svg+xml'}
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);
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}
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getSVGURL(renderer) {
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const blob = this.getSVGBlob(renderer);
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if(this.latestSVG) {
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URL.revokeObjectURL(this.latestSVG);
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}
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this.latestSVG = URL.createObjectURL(blob);
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return this.latestSVG;
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}
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getPNGBlob(renderer, resolution, callback) {
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if(!this.canvas) {
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window.devicePixelRatio = 1;
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this.canvas = document.createElement('canvas');
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this.context = this.canvas.getContext('2d');
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}
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const width = renderer.width * resolution;
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const height = renderer.height * resolution;
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const img = new Image(width, height);
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let safariHackaround = null;
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if(safari) {
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// Safari fails to resize SVG images unless they are displayed
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// on the page somewhere, so we must add it before drawing the
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// image. For some reason, doing this inside the load listener
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// is too late, so we do it here and do our best to ensure it
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// doesn't change the page rendering (display:none fails too)
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safariHackaround = document.createElement('div');
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safariHackaround.style.position = 'absolute';
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safariHackaround.style.visibility = 'hidden';
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safariHackaround.appendChild(img);
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document.body.appendChild(safariHackaround);
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}
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img.addEventListener('load', () => {
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this.canvas.width = width;
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this.canvas.height = height;
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this.context.drawImage(img, 0, 0);
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if(safariHackaround) {
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document.body.removeChild(safariHackaround);
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}
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this.canvas.toBlob(callback, 'image/png');
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}, {once: true});
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img.src = this.getSVGURL(renderer);
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}
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getPNGURL(renderer, resolution, callback) {
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++ this.indexPNG;
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const index = this.indexPNG;
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this.getPNGBlob(renderer, resolution, (blob) => {
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const url = URL.createObjectURL(blob);
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const isLatest = index >= this.latestPNGIndex;
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if(isLatest) {
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if(this.latestPNG) {
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URL.revokeObjectURL(this.latestPNG);
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}
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this.latestPNG = url;
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this.latestPNGIndex = index;
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callback(url, true);
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} else {
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callback(url, false);
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URL.revokeObjectURL(url);
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}
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});
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}
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};
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});
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