bug#12612: 24.2.50; Frame Background RGB(1,1,1) Darker Than Set Using GTK3

[Stephen Berman]

On Tue, 9 Oct 2012 14:11:09 -0400 Taylor Venable <tvenable@mieweb.com> wrote:

> When using GTK3, any time one sets the frame background (e.g. from
> startup, or using set-frame-parameter) there is a difference between the
> background color of the part of the frame with text, and the part of the
> frame without. The part with text is correct, but the part of the frame
> without is darker by 1 bit in all three RGB attributes. For example, the
> default background is white; if you take a screenshot and look at the
> result in the GIMP you will find that space between text is #ffffff,
> whereas the background after the end of the line or buffer is #fefefe.
>
> Only with GTK3 have I noticed this; with GTK2 this does not occur. 

I confirm both these observations.

> happens with -Q. You don't notice it with light (Emacs) themes, but on
> my monitor I can see it with darker (Emacs) themes fairly easily. When
> in doubt, you can always check with a screenshot. 

On my monitor (and with my eyes) I can't tell the difference, but when I
used a color picker program it showed just what you describe.

>                                                   The exception is if
> the background is set to #000000, in which case everything has a
> background of #000000 as it should.

I guess that's no exception, since there are no negative RGB values.

> I have no GTK3 theme set. Thanks for having a look.

I'm using oxygen-gtk on KDE4.

> In GNU Emacs 24.2.50.2 (x86_64-unknown-linux-gnu, GTK+ Version 3.4.4)
>  of 2012-10-09 on trantor
> Bzr revision: monnier@iro.umontreal.ca-20121009163751-ui2zwwoaj8bqwj52

Mine: GNU Emacs 24.2.50.1 (x86_64-suse-linux-gnu, GTK+ Version 3.4.4) of
2012-10-03 on rosalinde
Bzr revision 110349 eggert@cs.ucla.edu-20121002193810-gu1indup6lry2cxn

(Not seen on GNU Emacs 23.3.1 (x86_64-suse-linux-gnu, GTK+ Version
2.24.10) of 2012-08-15 on build21.)