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

JBrowse 2 core libraries used by plugins

import { CanvasSequence } from 'canvas-sequencer-ts';
import isNode from 'detect-node';
export { collectTransferables, isDetachedBuffer } from "./transferables.js";
export function isImageBitmap(value) {
    return typeof ImageBitmap !== 'undefined' && value instanceof ImageBitmap;
}
export function drawImageOntoCanvasContext(imageData, context) {
    if (imageData.serializedCommands) {
        const seq = new CanvasSequence(imageData.serializedCommands);
        seq.execute(context);
    }
    else {
        context.drawImage(imageData, 0, 0);
    }
}
export function createCanvas(width, height) {
    if (typeof OffscreenCanvas === 'function') {
        return new OffscreenCanvas(width, height);
    }
    else if (isNode) {
        return nodeCreateCanvas(width, height);
    }
    else {
        const context = new CanvasSequence();
        return {
            width,
            height,
            getContext() {
                return context;
            },
        };
    }
}
export async function createImageBitmap(canvas) {
    if (typeof OffscreenCanvas === 'function') {
        return canvas.transferToImageBitmap();
    }
    else if (isNode) {
        const dataUri = canvas.toDataURL();
        const img = new nodeImage();
        return new Promise((resolve, reject) => {
            img.onload = () => {
                resolve(img);
            };
            img.onerror = reject;
            img.src = dataUri;
        });
    }
    else {
        const ctx = canvas.getContext('2d');
        return {
            height: canvas.height,
            width: canvas.width,
            serializedCommands: ctx.toJSON(),
        };
    }
}