https://bugs.documentfoundation.org/show_bug.cgi?id=145988

--- Comment #55 from Patrick Luby <[email protected]> ---
(In reply to خالد حسني from comment #54)
> 
> No difference or messages reported for me. I also don’t think the issue is
> limited to images, even the thumbnails in the start center have their white
> color turned into yellow.

You have a good point about the document thumbnails in the Start Center so I
traced how they are drawn. After some experimentation, I think that the
document thumbnails as well as the Impress template icons are both rendered
using following steps:

1. An offscreen image is created
2. The offscreen image is cleared in white (this is what turns yellow)
3. The thumbnail image is drawn with an alpha mask on top of the offscreen
image
4. The offscreen image is drawn to the window

What is interesting to me is that I if I try to skip step 2 by disabling
drawing filled rectangles in SkiaSalGraphicsImpl::privateDrawAlphaRect() and
drawing filled polygons in SkiaSalGraphicsImpl::performDrawPolyPolygon(), the
offscreen image is still filled with white.

So, my current theory is that erasing the background of an offscreen image is
where the problem might be. My logic is that LibreOffice colors set alpha
values to 1 - Skia's alpha value. What this means is that LibreOffice white
color in  ARGB format is #00ffffff. Copy this bit for bit directly to a Skia
white color in BGRA format results in yellow.

I post more when I find the code that clears offscreen images.

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