tree 4b149f9804477d53d2c5366f1cee165c02be83ec
parent f853785cb85b57e9c8af5dd1ce7c01d1ce9af60b
author Jean-Philippe Gravel <jpgravel@chromium.org> 1680642899 -0700
committer Blink WPT Bot <blink-w3c-test-autoroller@chromium.org> 1680643746 -0700

Add support for "dropShadow" in CanvasFilter.

This is based on the SVG feDropShadow specification:
https://drafts.fxtf.org/filter-effects/#feDropShadowElement

There are a few known limitations right now:
 - SVG's feDropShadow supports different blur values for the X and
   the Y directions. We can't easily support this with CanvasFilter
   right now because it's implemented by leveraging the CSS code
   and CSS doesn't support different X/Y blur values.

 - For now, `currentColor` and `color-scheme` are not supported.
   These depend on the DOM element computed style, which is not
   available when we do `new CanvasFilter(...)`. To support
   `CurrentColor` and `color-schemes`, we would need maintain
   unresolved colors in the CanvasFilter object and resolve these
   colors only when the filter is assigned to a canvas element
   context. This is possible, but it's better if we only add this
   complexity if it's really needed.

Change-Id: I402c8a43c9e227ac3e5f363aee1946619a408716
Bug: 1428652
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4386673
Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Commit-Queue: Jean-Philippe Gravel <jpgravel@chromium.org>
Reviewed-by: Aaron Krajeski <aaronhk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1126225}