Non-standard This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.
The non-standard HTMLCanvasElement.mozOpaque
property is a Boolean
reflecting the moz-opaque
HTML attribute of the <canvas>
element. It lets the canvas know whether or not translucency will be a factor. If the canvas knows there's no translucency, painting performance can be optimized.
This has been standardized as setting the alpha
option to false
when creating a drawing context with HTMLCanvasElement.getContext()
. Use of mozOpaque
should be avoided. Firefox will stop supporting it in the future.
Syntax
var opaque = canvas.mozOpaque; canvas.mozOpaque = true;
Examples
Given this <canvas>
element:
<canvas id="canvas" width="300" height="300" moz-opaque></canvas>
You can get or set the mozOpaque
property. For example, you could conditionally set it to true
if mimeType == 'image/jpeg'
, or similar, to gain performance in your application when translucency is not needed.
var canvas = document.getElementById('canvas');
console.log(canvas.mozOpaque); // true
// deactivate it
canvas.mozOpaque = false;
Specifications
Not part of any standard.
Browser compatibility
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Update compatibility data on GitHub
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Chrome
No support No |
Edge
No support No |
Firefox
Full support 3 |
IE
No support No |
Opera
No support No |
Safari
No support No |
WebView Android
No support No |
Chrome Android
No support No |
Firefox Android
Full support 4 |
Opera Android
No support No |
Safari iOS
No support No |
Samsung Internet Android
No support No |
Legend
- Full support
- Full support
- No support
- No support
- Non-standard. Expect poor cross-browser support.'
- Non-standard. Expect poor cross-browser support.
See also
- The interface defining it,
HTMLCanvasElement
. - The
moz-opaque
HTML attribute of the<canvas>
element. - Optimizing your JavaScript game for Firefox OS
HTMLCanvasElement.mozOpaque by Mozilla Contributors is licensed under CC-BY-SA 2.5.