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From: Stefan Kangas <stefankangas@gmail.com>
To: Po Lu <luangruo@yahoo.com>
Cc: 59242@debbugs.gnu.org, Evgeny Zajcev <lg.zevlg@gmail.com>
Subject: bug#59242: 29.0.50; Poor quality for WebP images
Date: Mon, 14 Aug 2023 02:11:56 +0200	[thread overview]
Message-ID: <CADwFkmkkxg87fMpSaDcOr4PmuJ9eU5HqkmWeT2gXYKyxmwmLog@mail.gmail.com> (raw)
In-Reply-To: <877czzkx3d.fsf@yahoo.com>

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tags 59242 + patch
thanks

Po Lu <luangruo@yahoo.com> writes:

> > Evgeny Zajcev <lg.zevlg@gmail.com> writes:
>
> > Looks like partial transparency is incorrectly applied for webp images.

Thanks for the bug report.

> Stefan, I see the following code in image.c:
[...]
> So if the webp library does not blend itself, I think we will have to do
> that for it.  Am I missing anything here?

Yes, the old code was not right.  The attached patch should add proper
alpha blending for webp images.  I have tested it with the example
images here: https://developers.google.com/speed/webp/gallery2

Evgeny, could you please test this patch and report back?  It should
apply cleanly both against master and emacs-29.

[-- Attachment #2: 0001-Fix-alpha-blending-for-webp-images.patch --]
[-- Type: application/x-patch, Size: 3808 bytes --]

  reply	other threads:[~2023-08-14  0:11 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-13  8:48 bug#59242: 29.0.50; Poor quality for WebP images Evgeny Zajcev
2022-11-13  9:44 ` Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-08-14  0:11   ` Stefan Kangas [this message]
2023-08-14  2:33     ` Eli Zaretskii
2023-08-14  7:08       ` Stefan Kangas
2023-08-25 18:28     ` Stefan Kangas

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