87 wiersze
2.3 KiB
TypeScript
87 wiersze
2.3 KiB
TypeScript
import React from "react";
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function getSvgMarkup(el: SVGSVGElement): string {
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return [
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`<?xml version="1.0" encoding="utf-8"?>`,
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"<!-- Generator: https://github.com/toolness/mystic-symbolic -->",
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'<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">',
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el.outerHTML,
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].join("\n");
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}
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type ImageExporter = (svgEl: SVGSVGElement) => Promise<string>;
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/**
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* Initiates a download on the user's browser which downloads the given
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* SVG element under the given filename, using the given export algorithm.
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*/
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async function exportImage(
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svgRef: React.RefObject<SVGSVGElement>,
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basename: string,
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ext: string,
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exporter: ImageExporter
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) {
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const svgEl = svgRef.current;
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if (!svgEl) {
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alert("Oops, an error occurred! Please try again later.");
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return;
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}
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const url = await exporter(svgEl);
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const anchor = document.createElement("a");
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anchor.href = url;
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anchor.download = `${basename}.${ext}`;
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document.body.append(anchor);
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anchor.click();
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document.body.removeChild(anchor);
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}
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function getCanvasContext2D(
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canvas: HTMLCanvasElement
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): CanvasRenderingContext2D {
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const ctx = canvas.getContext("2d");
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if (!ctx) throw new Error(`Unable to get 2D context for canvas!`);
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return ctx;
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}
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/**
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* Exports the given SVG as an SVG in a data URL.
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*/
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const exportSvg: ImageExporter = async (svgEl) =>
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`data:image/svg+xml;utf8,${encodeURIComponent(getSvgMarkup(svgEl))}`;
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/**
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* Exports the given SVG as a PNG in a data URL.
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*/
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const exportPng: ImageExporter = async (svgEl) => {
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const dataURL = await exportSvg(svgEl);
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return new Promise((resolve, reject) => {
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const canvas = document.createElement("canvas");
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const img = document.createElement("img");
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img.onload = () => {
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canvas.width = img.width;
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canvas.height = img.height;
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const ctx = getCanvasContext2D(canvas);
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ctx.drawImage(img, 0, 0);
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resolve(canvas.toDataURL());
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};
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img.onerror = reject;
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img.src = dataURL;
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});
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};
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export const ExportWidget: React.FC<{
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svgRef: React.RefObject<SVGSVGElement>;
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basename: string;
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}> = ({ svgRef, basename }) => (
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<>
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<button onClick={() => exportImage(svgRef, basename, "svg", exportSvg)}>
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Export SVG
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</button>{" "}
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<button onClick={() => exportImage(svgRef, basename, "png", exportPng)}>
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Export PNG
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</button>
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</>
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);
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