[svgwg] What is the purpose of BackgroundImage filter input in SVG 2? (#910)

RazrFalcon has just created a new issue for https://github.com/w3c/svgwg:

== What is the purpose of BackgroundImage filter input in SVG 2? ==
https://www.w3.org/TR/filter-effects-1/#attr-valuedef-in-backgroundimage

In SVG 1, `BackgroundImage` was used in tandem with `enable-background` to render part of SVG into a filter input buffer.
In SVG 2, there are no `enable-background` anymore (no one really supported it anyway) and the spec simply says:

>This keyword represents the back drop defined by the current isolation group behind the filter region at the time that the filter element was invoked. See isolation property.

But the `filter` attribute always forces group isolation, meaning it the same as using `SourceGraphic`, no?

And browsers do not support it either. Chrome does handle `BackgroundImage` sometimes (probably simply fallbacks to `SourceGraphic`), but not `BackgroundAlpha`.

What is the difference between `SourceGraphic` and `BackgroundImage` in terms of SVG 2?

Please view or discuss this issue at https://github.com/w3c/svgwg/issues/910 using your GitHub account


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Received on Sunday, 23 April 2023 15:20:33 UTC