bug#56182: 28.1; Display of SVG file with transparent background is incorrect

[Alan Third]

On Tue, Jun 28, 2022 at 08:38:11PM +0200, Pascal Quesseveur wrote:
> >"AT" == Alan Third <alan@idiocy.org> a écrit :
> 
>   AT> I can't reproduce it.
> 
> From what I understand the way to deal with background transparency of
> SVG images has changed in version 28.1 in function svg_load_image
> (comments about opacity are still there but I think they are
> irrelevant). Now the SVG image is encapsulated in another SVG image in
> which a rect element is defined with the background color of the
> image.

Can you try using describe-face to compare the face where the image is
and another place where the background colour is shown correctly?


> I don't know why it doesn't work on the W10 computers I work on. I
> don't know if the problem comes from this modificatino either. It
> seems to me that the displayed color is BGR instead of RGB and the
> screen gamma correction is not applied. For what it's worth I managed
> to work around the problem in lisp. With version 27.1 I had
> implemented an advice to improve the taking into account of the
> background color in the style of SVG file. So I extended that advice
> to solve my problem.

*scratches head*

Eli, do we need to decode the "unsigned long" colours in a special way
on Windows? It could be I've missed a vital step and am using them
incorrectly. So if the colour is defined in BGR byte order, and I then
use the unsigned long directly in a printf("#%06X", colour) style,
that's likely to be wrong, yes?

-- 
Alan Third