demo · v134
OffscreenCanvas.getContextAttributes
OffscreenCanvas contexts now expose getContextAttributes(), matching the HTML <canvas> behaviour. Useful for verifying alpha / colorSpace / desynchronized / willReadFrequently — especially when the offscreen context lives on a worker. Pick options, request the context, and the page reports what came back, both on the main thread and from a real Worker.
probing OffscreenCanvas...
Try it
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The code
const off = new OffscreenCanvas(100, 100);
const ctx = off.getContext("2d", { alpha: false, willReadFrequently: true });
console.log(ctx.getContextAttributes());
// {alpha: false, willReadFrequently: true, colorSpace: "srgb", ...}