This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for the proper prefixes to use in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the spec changes.
The OffscreenCanvas.toBlob() method creates a Blob object representing the image contained in the canvas.
Promise<Blob> OffscreenCanvas.toBlob(type, encoderOptions);
type Optional
DOMString indicating the image format. The default type is image/png.encoderOptions Optional
Number between 0 and 1 indicating image quality if the requested type is image/jpeg or image/webp. If this argument is anything else, the default value for image quality is used. Other arguments are ignored.A Promise returning a Blob object representing the image contained in the canvas.
var offscreen = new OffscreenCanvas(256, 256);
var gl = offscreen.getContext("webgl");
// ... some drawing using the gl context ...
offscreen.toBlob().then(function(blob) {
console.log(blob);
});
// Blob { size: 334, type: "image/png" } Currently drafted as a proposal: OffscreenCanvas.
| Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|
| Basic support | Not supported | 46 (46) [1] | Not supported | Not supported | Not supported |
| Feature | Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|
| Basic support | Not supported | 46.0 (46) [1] | Not supported | Not supported | Not supported |
[1] This feature is behind a feature preference setting. In about:config, set gfx.offscreencanvas.enabled to true.
OffscreenCanvas.
© 2005–2017 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/OffscreenCanvas/toBlob