OffscreenCanvas.convertToBlob()

The OffscreenCanvas.convertToBlob() method creates a Blob object representing the image contained in the canvas.

Syntax

Promise<Blob> OffscreenCanvas.convertToBlob(options);

Parameters

optionsOptional

You can specify several options when converting your OffscreenCanvas object into a Blob object, for example:

const blob = offscreenCanvas.convertToBlob({
  type: "image/jpeg",
  quality: 0.95
});

options:

• type: A DOMString indicating the image format. The default type is image/png.
• quality: A Number between 0 and 1 indicating image quality if the type option is image/jpeg or image/webp. If this argument is anything else, the default value for image quality is used. Other arguments are ignored.

Return value

A Promise returning a Blob object representing the image contained in the canvas.

Examples

var offscreen = new OffscreenCanvas(256, 256);
var gl = offscreen.getContext("webgl");

// ... some drawing using the gl context ...

offscreen.convertToBlob().then(function(blob) {
  console.log(blob);
});

// Blob { size: 334, type: "image/png" }

Specifications

Browser compatibility

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	WebView Android	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet
convertToBlob	69	79	46 See bug 1390089.	No	56	No	No	69	46 See bug 1390089.	48	No	10.0

See also

• The interface defining this method, OffscreenCanvas.