Bug 83051 – [Cairo] SVG shadows show through opaque objects

• Status: NEW
• Component: SVG

[Philip Rogers]

SVG shadows show through opaque objects, causing the test "svg/css/group-with-shadow.svg" to fail on skia platforms.

For a repro, just open LayoutTests/svg/css/group-with-shadow.svg and notice the faint grey shadow on top of the purple box. It's much easier to see if you change the testcase to use a white box, and I would recommend that this testcase be changed so busy sheriffs don't make the same mistake again and check in incorrect expectations.

[Philip Rogers]

Created attachment 135375 [details]
Update test expectations so this test fails instead of silently passing

[Peter Kasting]

Comment on attachment 135375 [details]
Update test expectations so this test fails instead of silently passing

This patch landed long ago.

[Dirk Schulze]

Looking at the implementation, Cairo might still be affected. CC: mrobinson

[Martin Robinson]

The original bug seems to be about the Skia backend. What about the Cairo implementation looks broken to you?

[Dirk Schulze]

(In reply to comment #4)
> The original bug seems to be about the Skia backend. What about the Cairo implementation looks broken to you?

It was implemented by Aryeh in a platform independent way for Cairo and Qt.

Here is the link to the test: http://trac.webkit.org/export/168780/trunk/LayoutTests/svg/css/group-with-shadow.svg Compare it to http://trac.webkit.org/export/168780/trunk/LayoutTests/platform/mac/svg/css/group-with-shadow-expected.png

Also, try a tests where elements are overlapping and apply the shadow on a group element: http://jsfiddle.net/rTPaG/

Is the shadow drawn for the group (as it should be) or for each element individually?

[Martin Robinson]

(In reply to comment #5)

> Is the shadow drawn for the group (as it should be) or for each element individually?


In the jsfiddle example the shadow is drawn for each element individually.

[Martin Robinson]

(In reply to comment #5)

> Here is the link to the test: http://trac.webkit.org/export/168780/trunk/LayoutTests/svg/css/group-with-shadow.svg Compare it to http://trac.webkit.org/export/168780/trunk/LayoutTests/platform/mac/svg/css/group-with-shadow-expected.png

The faint shadow also appears in the Mac expected results, so is this also an issue with the CG backend?