@infinite-canvas-tutorial/webcomponents/esm/systems/DownloadScreenshot.js

WebComponents UI implementation

import { Canvas, DOMAdapter, Screenshot, System, } from '@infinite-canvas-tutorial/ecs';
import { Event } from '../event';
const downloadedFilename = 'infinite-canvas-screenshot';
export class DownloadScreenshot extends System {
    constructor() {
        super();
        this.screenshots = this.query((q) => q.added.with(Screenshot));
        this.query((q) => q.using(Canvas).read);
    }
    execute() {
        this.screenshots.added.forEach((screenshot) => {
            const { dataURL, svg, canvas, download } = screenshot.read(Screenshot);
            if (download) {
                this.downloadImage(downloadedFilename, dataURL);
            }
            const api = canvas.read(Canvas).api;
            api.element.dispatchEvent(new CustomEvent(Event.SCREENSHOT_DOWNLOADED, {
                detail: {
                    dataURL,
                    svg,
                },
            }));
        });
    }
    downloadImage(defaultFilename, dataURL) {
        const mimeType = dataURL.substring(dataURL.indexOf(':') + 1, dataURL.indexOf(';'));
        const suffix = mimeType.split('/')[1];
        // g-svg only support .svg
        const isSVG = dataURL.startsWith('data:image/svg');
        const fileName = `${defaultFilename}.${isSVG ? 'svg' : suffix}`;
        const link = DOMAdapter.get()
            .getDocument()
            .createElement('a');
        if (isSVG) {
            link.addEventListener('click', () => {
                link.download = fileName;
                link.href = dataURL;
            });
        }
        else if (window.Blob && window.URL) {
            const arr = dataURL.split(',');
            let mime = '';
            if (arr && arr.length > 0) {
                const match = arr[0].match(/:(.*?);/);
                // eslint-disable-next-line prefer-destructuring
                if (match && match.length >= 2)
                    mime = match[1];
            }
            const bstr = atob(arr[1]);
            let n = bstr.length;
            const u8arr = new Uint8Array(n);
            while (n--) {
                u8arr[n] = bstr.charCodeAt(n);
            }
            const blobObj = new Blob([u8arr], { type: mime });
            // account for IE
            // @see https://stackoverflow.com/a/41434373
            if (navigator.msSaveBlob) {
                navigator.msSaveBlob(blobObj, fileName);
            }
            else {
                link.addEventListener('click', () => {
                    link.download = fileName;
                    link.href = window.URL.createObjectURL(blobObj);
                });
            }
        }
        // trigger click
        if (link.click) {
            link.click();
        }
        else {
            const e = DOMAdapter.get().getDocument().createEvent('MouseEvents');
            e.initEvent('click', false, false);
            link.dispatchEvent(e);
        }
    }
}
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