* bug#22253: Background of transparent PNG images uses default background color, instead of current one
@ 2015-12-28 2:45 Clément Pit--Claudel
2019-08-01 16:59 ` Lars Ingebrigtsen
0 siblings, 1 reply; 3+ messages in thread
From: Clément Pit--Claudel @ 2015-12-28 2:45 UTC (permalink / raw)
To: 22253
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Hi all,
When no :background is specified for a transparent PNG, the background color of the 'default face is used. This causes aliasing effect to appear then e.g. the image is highlighted (transient-mark-mode).
To reproduce (on latest emacs-25):
* Save https://i.stack.imgur.com/BqrLK.png as ~/rooster.png
* emacs -Q
M-: (insert #(" 🐤" 1 2
(display
(image :type imagemagick :file "~/rooster.png" :ascent center :mask heuristic :height 150))))
* Notice that the picture looks perfectly antialiased against the default white background
* C-x h
* Notice the aliasing
Can I provide more information on this bug?
Cheers,
Clément.
In GNU Emacs 25.0.50.2 (x86_64-unknown-linux-gnu, GTK+ Version 3.10.8)
of 2015-10-20
Repository revision: 13274cd5d9eb87273c14656084286d5321193858
Windowing system distributor 'The X.Org Foundation', version 11.0.11501000
System Description: Linux Mint 17.2 Rafaela
Configured using:
'configure CFLAGS=-O3'
Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GCONF GSETTINGS
NOTIFY ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11
Important settings:
value of $LC_TIME: en_DK.UTF-8
value of $LANG: en_US.UTF-8
value of $XMODIFIERS: @im=ibus
locale-coding-system: utf-8-unix
Major mode: Lisp Interaction
Minor modes in effect:
tooltip-mode: t
global-eldoc-mode: t
electric-indent-mode: t
mouse-wheel-mode: t
tool-bar-mode: t
menu-bar-mode: t
file-name-shadow-mode: t
global-font-lock-mode: t
font-lock-mode: t
blink-cursor-mode: t
auto-composition-mode: t
auto-encryption-mode: t
auto-compression-mode: t
line-number-mode: t
transient-mark-mode: t
Load-path shadows:
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Memory information:
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^ permalink raw reply [flat|nested] 3+ messages in thread
* bug#22253: Background of transparent PNG images uses default background color, instead of current one
2015-12-28 2:45 bug#22253: Background of transparent PNG images uses default background color, instead of current one Clément Pit--Claudel
@ 2019-08-01 16:59 ` Lars Ingebrigtsen
2019-09-26 16:22 ` Lars Ingebrigtsen
0 siblings, 1 reply; 3+ messages in thread
From: Lars Ingebrigtsen @ 2019-08-01 16:59 UTC (permalink / raw)
To: Clément Pit--Claudel; +Cc: 22253
Clément Pit--Claudel <clement.pitclaudel@live.com> writes:
> When no :background is specified for a transparent PNG, the background color of the 'default face is used. This causes aliasing effect to appear then e.g. the image is highlighted (transient-mark-mode).
>
> To reproduce (on latest emacs-25):
>
> * Save https://i.stack.imgur.com/BqrLK.png as ~/rooster.png
> * emacs -Q
> M-: (insert #(" 🐤" 1 2
> (display
> (image :type imagemagick :file "~/rooster.png" :ascent center :mask heuristic :height 150))))
> * Notice that the picture looks perfectly antialiased against the default white background
> * C-x h
> * Notice the aliasing
The only way to fix this would be to re-generate the images whenever the
background colour of the image changes, I guess? Or to support alpha
channels directly in the display engine, and I don't think we have
support for that?
--
(domestic pets only, the antidote for overdose, milk.)
bloggy blog: http://lars.ingebrigtsen.no
^ permalink raw reply [flat|nested] 3+ messages in thread
* bug#22253: Background of transparent PNG images uses default background color, instead of current one
2019-08-01 16:59 ` Lars Ingebrigtsen
@ 2019-09-26 16:22 ` Lars Ingebrigtsen
0 siblings, 0 replies; 3+ messages in thread
From: Lars Ingebrigtsen @ 2019-09-26 16:22 UTC (permalink / raw)
To: Clément Pit--Claudel; +Cc: 22253
Lars Ingebrigtsen <larsi@gnus.org> writes:
> The only way to fix this would be to re-generate the images whenever the
> background colour of the image changes, I guess? Or to support alpha
> channels directly in the display engine, and I don't think we have
> support for that?
We don't, so I don't think there's any realistic way to fix this glitch.
I'm closing this bug report, but if anybody has a transparently bright
idea here, please reopen.
--
(domestic pets only, the antidote for overdose, milk.)
bloggy blog: http://lars.ingebrigtsen.no
^ permalink raw reply [flat|nested] 3+ messages in thread
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2015-12-28 2:45 bug#22253: Background of transparent PNG images uses default background color, instead of current one Clément Pit--Claudel
2019-08-01 16:59 ` Lars Ingebrigtsen
2019-09-26 16:22 ` Lars Ingebrigtsen
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