@jbrowse/core/esm/util/renderToAbstractCanvas.js

JBrowse 2 core libraries used by plugins

import { CanvasSequence } from 'canvas-sequencer-ts';
import { blobToDataURL } from "./blobToDataURL.js";
import { createCanvas, createImageBitmap } from "./offscreenCanvasPonyfill.js";
export async function renderToAbstractCanvas(width, height, opts, cb) {
    const { exportSVG, highResolutionScaling = 1 } = opts;
    const safeWidth = Math.max(1, width);
    const safeHeight = Math.max(1, height);
    if (exportSVG) {
        if (!exportSVG.rasterizeLayers) {
            const fakeCtx = new CanvasSequence();
            const callbackResult = await cb(fakeCtx);
            return {
                ...callbackResult,
                canvasRecordedData: fakeCtx.toJSON(),
            };
        }
        else {
            const s = exportSVG.scale || highResolutionScaling;
            const canvas = createCanvas(Math.ceil(safeWidth * s), Math.ceil(safeHeight * s));
            const ctx = canvas.getContext('2d');
            if (!ctx) {
                throw new Error('2d canvas rendering not supported on this platform');
            }
            if (s !== 1) {
                ctx.scale(s, s);
            }
            const callbackResult = await cb(ctx);
            return {
                ...callbackResult,
                html: `<image width="${width}" height="${height}" href="${'convertToBlob' in canvas
                    ? await blobToDataURL(await canvas.convertToBlob({
                        type: 'image/png',
                    }))
                    : canvas.toDataURL('image/png')}" />`,
            };
        }
    }
    else {
        const canvas = createCanvas(Math.ceil(safeWidth * highResolutionScaling), Math.ceil(safeHeight * highResolutionScaling));
        const ctx = canvas.getContext('2d');
        if (!ctx) {
            throw new Error('2d canvas rendering not supported on this platform');
        }
        if (highResolutionScaling !== 1) {
            ctx.scale(highResolutionScaling, highResolutionScaling);
        }
        const callbackResult = await cb(ctx);
        return {
            ...callbackResult,
            imageData: await createImageBitmap(canvas),
        };
    }
}