From: mituharu@math.s.chiba-u.ac.jp
To: "Roland Winkler" <winkler@gnu.org>
Cc: 37153@debbugs.gnu.org, Paul Eggert <eggert@cs.ucla.edu>
Subject: bug#37153: 26.1; some png images scrambled
Date: Sat, 24 Aug 2019 18:01:46 +0900 [thread overview]
Message-ID: <9c4c68ebe20cbcc44763be8e72bd25eb.squirrel@weber.math.s.chiba-u.ac.jp> (raw)
In-Reply-To: <44134.15891.158963.23904@gargle.gargle.HOWL>
> On Fri Aug 23 2019 Paul Eggert wrote:
>> Do you see the same problem when using Emacs master? If not, then
>> perhaps we can just marked the bug as fixed in the next release.
>
> The problem with my test png image is that it has transparent parts
> that need to be displayed with a light color so that one can
> recognize the nontransparent dark parts. But the image uses fully
> transparent black as background. The behavior in such a case is not
> strictly defined by the png standard, see
>
> https://sourceforge.net/p/png-mng/mailman/message/36747189/
>
> Emacs displays such fully transparent background with its original
> color specified by the image. But I believe it would make more
> sense if emacs used instead a background color that the user can
> choose (the background color of the frame), similar to, for example,
> eog.
I suspect there is a longstanding typo (or thinko) in PNG
transparency handling code.
YAMAMOTO Mitsuharu
mituharu@math.s.chiba-u.ac.jp
diff --git a/src/image.c b/src/image.c
index 81d8cb4e2b2..819e058f7e1 100644
--- a/src/image.c
+++ b/src/image.c
@@ -6680,7 +6680,7 @@ png_load_body (struct frame *f, struct image *img,
struct png_load_context *c)
/* Create an image and pixmap serving as mask if the PNG image
contains an alpha channel. */
if (channels == 4
- && !transparent_p
+ && transparent_p
&& !image_create_x_image_and_pixmap (f, img, width, height, 1,
&mask_img, 1))
{
next prev parent reply other threads:[~2019-08-24 9:01 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-23 4:49 bug#37153: 26.1; some png images scrambled Roland Winkler
2019-08-23 8:47 ` Eli Zaretskii
2019-08-23 11:39 ` Roland Winkler
2019-08-23 12:22 ` Eli Zaretskii
2019-08-23 15:07 ` Roland Winkler
2019-08-23 15:34 ` Eli Zaretskii
2019-08-23 19:37 ` Paul Eggert
2019-08-23 20:11 ` Eli Zaretskii
2019-08-23 20:33 ` Paul Eggert
2019-08-24 5:51 ` Eli Zaretskii
2019-08-24 3:17 ` Roland Winkler
2019-08-24 3:39 ` Paul Eggert
2019-08-24 4:19 ` Roland Winkler
2019-08-24 6:26 ` Eli Zaretskii
2019-08-24 6:22 ` Eli Zaretskii
2019-08-24 9:01 ` mituharu [this message]
2019-08-24 10:17 ` Eli Zaretskii
2019-08-25 4:19 ` YAMAMOTO Mitsuharu
2019-08-25 7:24 ` Eli Zaretskii
2019-08-25 4:52 ` Roland Winkler
2019-08-25 6:58 ` YAMAMOTO Mitsuharu
2019-08-25 12:19 ` Roland Winkler
2019-08-25 18:38 ` Paul Eggert
2019-08-25 18:56 ` Eli Zaretskii
2019-08-25 23:02 ` YAMAMOTO Mitsuharu
2019-08-25 23:06 ` YAMAMOTO Mitsuharu
2019-08-25 23:39 ` Paul Eggert
2019-09-24 16:23 ` Lars Ingebrigtsen
2019-09-24 17:14 ` Eli Zaretskii
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