Bug 163165 - With Skia, semi-transparent area in shapes is opaque during animation
Summary: With Skia, semi-transparent area in shapes is opaque during animation
Status: NEW
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: Impress (show other bugs)
Version:
(earliest affected)
unspecified
Hardware: All All
: medium normal
Assignee: Not Assigned
URL:
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Keywords:
Depends on:
Blocks: Skia
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Reported: 2024-09-26 12:46 UTC by Mike Kaganski
Modified: 2024-09-30 19:49 UTC (History)
4 users (show)

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Description Mike Kaganski 2024-09-26 12:46:54 UTC 
Use Skia. Open attachment 196675 [details] from bug 163145. Run the presentation.

The fading circle is not visible through the semi-transparent area of the upper rectangle.

With Skia disabled, it works as expected.

Already works like that using Version: 7.0.0.3 (x64)
Build ID: 8061b3e9204bef6b321a21033174034a5e2ea88e
CPU threads: 24; OS: Windows 10.0 Build 26100; UI render: Skia/Vulkan; VCL: win
Locale: ru-RU (ru_RU); UI: en-US
Calc: CL

and with OpenGL before that, using e.g. Version: 5.3.0.3 (x64)
Build ID: 7074905676c47b82bbcfbea1aeefc84afe1c50e1
CPU Threads: 24; OS Version: Windows 6.19; UI Render: GL; Layout Engine: new; 
Locale: en-US (ru_RU); Calc: CL
Comment 1 Buovjaga 2024-09-26 12:53:03 UTC 
Repro.

Version: 25.2.0.0.alpha0+ (X86_64) / LibreOffice Community
Build ID: 12e08b3cba0e75f1bd3a42f30e4830d723b24ece
CPU threads: 8; OS: Linux 6.10; UI render: Skia/Vulkan; VCL: x11
Locale: fi-FI (fi_FI.UTF-8); UI: en-US
Calc: CL threaded
Comment 2 Mike Kaganski 2024-09-27 03:54:15 UTC 
Basically, Skia now shows the same problem as bug 45219, with its attachment 56132 [details].

It is unclear how useful it is, that we have that 1-bit transparency still. The problem is related to the handling of mp2ndOutDevProvider in vclcanvas::CanvasHelper::fillPolyPolygon.

But maybe a fix similar to commits in that bug could help here in Skia code, too...