GNOME Bugzilla – Bug 335057
wrong colours in panel background image
Last modified: 2020-11-06 20:26:19 UTC
Please describe the problem: Using a background image for the gnome-panel that has any transparency results in the wrong colours for the image. Black goes to blue, yellow goes to white, transparency goes to yellow, and so on. Steps to reproduce: 1. Drag an image that has any transparent section to gnome-panel (or select that image with gnome-panel properties dialog). 2. Observe how the colours of the image in the panel are not the colours of the original image. Actual results: The colours of the image in gnome-panel are not the same as in the original. Expected results: The image in the panel has the same colours as the original. Does this happen every time? Yes Other information: Tested with png and svg files. Tested on Fedora Core 5 and Ubuntu Dapper 6.04 (both test versions of these distros updated after the final GNOME 2.14 release). Tested on two computers, one with onboard intel graphics, one with ATI card using open source drivers for both cards. This behaviour was not present until GNOME 2.13
Does it depend on your desktop background? Also, can you attach your test images to this bug? Thanks
Created attachment 61534 [details] screenshot of the reverse-colour effect
(In reply to comment #1) > Does it depend on your desktop background? > Also, can you attach your test images to this bug? > > Thanks > The effect is seen with all desktop-backgrounds I've tried, which are all jpegs or pngs. Also with a blank desktop-background. The only effect changing the desktop-background has had is changing the panel colour slightly, since the image used for the panel is partially transparent.
Ok, I can reproduce here with such an image (the new dasher icon, eg).
Mentioned in https://launchpad.net/distros/ubuntu/+source/gnome-panel/+bug/35768 as well.
May also be related to this bug: https://launchpad.net/distros/ubuntu/+source/gnome-panel/+bug/38185 (which is about a panel using flat color, but setting "transparency" to 100%)
https://launchpad.net/distros/ubuntu/+source/gnome-panel/+bug/42677 is also about that. It seems to be dependant of the background used. It happens with a vertical color gradient on my box but not with a background image
From https://launchpad.net/distros/ubuntu/+source/gnome-panel/+bug/42677: "Configure panel using properties. Select solid color background for panel, preferably a light one, then slide the transparancy bar back and forth. When the slider is on transparant the Ubuntu caramel color shows. ... > Thanks for your bug. What version of Ubuntu do you use? Could you make a screenshot of the issue? What GTK theme do you use? That works fine for me ... http://librarian.launchpad.net/2514443/transparent.png See above http://librarian.launchpad.net/2514444/opaqueback.png Screenshot of opaque background. ..."
Mentioned here -> http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=366991
Created attachment 68157 [details] [review] handle no background "ok" This patch tries to fix the issue. The problem is that when using a solid color background, the background color of the root window is changed and no background pixmap is set. Unfortunately, a) background colors are not queryable b) gnome-panel has no nice handling for the error case of "no pixmap" This patch makes gnome-panel use the default background when the background can not be determined and ignores any potential shading that might have been set. The other option would have been to just use the shading color to render the background opaque. This caused issues though when the background was supposed to be shaded with black, because that causes a solid black background. So I decided against that approach.
I should probably be explicit, that the patch only fixes bugs with a solid color background, so it might not fix the problems people are having here. And I should have mentioned that the patch adds support for screen size changes.
Benjamin: I committed the first part of the patch (screen size change), but not the second part. Unfortunately, it doesn't work well when you just kill nautilus and use "xsetroot -solid blue". I didn't try to see if it can be fixed. Also, this should be in a new bug, not in this one :-) Thanks
Shouldn't this be closed as "Fixed"? This hasn't been an issue for several releases now. Or does it have to be fixed for the version the bug was opened on?
bugzilla.gnome.org is being replaced by gitlab.gnome.org. We are closing all old bug reports in Bugzilla which have not seen updates for many years. If you can still reproduce this issue in a currently supported version of GNOME (currently that would be 3.38), then please feel free to report it at https://gitlab.gnome.org/GNOME/gnome-panel/-/issues/ Thank you for reporting this issue and we are sorry it could not be fixed.