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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 and internal only CanvasRenderingContext2D.drawWidgetAsOnScreen() method of the Canvas 2D API renders the root widget of a window into the canvas. Unlike drawWindow(), this API uses the operating system to snapshot the widget on-screen, rather than reading from Gecko's own compositor.

This API cannot be used by Web content. It is only supported on Windows, only on widgets that use OMTC, and only from within the chrome process.


void ctx.drawWidgetAsOnScreen(window);


The Window to render.


Not part of any current specification or draft. This is a non-standard and internal only API.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support No support 41 (41) No support No support No support
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support No support No support 41.0 (41) No support No support No support

See also

Document Tags and Contributors

 Contributors to this page: fscholz
 Last updated by: fscholz,