Hi,
running on Ubuntu 11.04
I found similar topic, where some experimental “theme” feature was suggested, but it seems it doesn’t work for current version
Also I care just for waveform background, GUI doesn’t bother me
How can I change waveform background to black?
The simplest may be to use (or edit) one of these ready-made themes, following the instructions given to set audacity.cfg to load the theme:
http://jcsu.jesus.cam.ac.uk/~hdc21/design/audacity/ .
Otherwise (assuming you are using Audacity 1.3.9 or later) Audacity cannot create ImageCache.png or the individual theme files for you to edit because Theming is disabled. You can read about the limited and somewhat buggy Theming feature at
http://manual.audacityteam.org/man/Theme_Preferences .
If you want a current build with Theming enabled, build Audacity from source code, either the source tarball:
http://audacityteam.org/download/source#recdown
or current HEAD:
http://wiki.audacityteam.org/wiki/CompilingAudacityForBeginners#simple
then you can enable #define EXPERIMENTAL_THEME_PREFS in src/Experimental.h by removing the two “//” in front of the define. There is also a #define EXPERIMENTAL_THEMING which sets a specific theme but it’s unknown how that reacts to a dark operating system theme like Ubuntu’s default theme.
Gale
Thanks for your explanations, Gale 
I did what you suggested - I enabled “experimental theme prefs” support and rebuild Audacity.
However, it was all just too much trouble for nothing.
First, I needed to guess which color box matches which widget, from ImageCache.png, finally ending by replacing all color boxes #C0C0C0 (192,192,192) to black. There were 5-6 boxes IIRC, but unfortunately all that was changed by this action, was waveform background. Spectrogram and Pitch background remained the same as they were #BFBFBF (191,191,191) without reference color box in ImageCache.png file.
I haven’t yet found application that by default uses light background for color spectrogram, except of course Audacity.
By other suggestion, I also tried adjusting colordefs in “src/AllThemeResources.h” (clrBlank, clrUnselected…) without visible result
Then I revert everything just as it was, as I didn’t want experimental features for nothing
Thinking about this topic, IMHO what Audacity “should” provide to end user is setting colors for view widget (of whatever it is called) with additional colormap selection for spectrogram view. That’s not hard thing to provide, and is provided by all audio editors I know of, instead patch-worked “theme” support which is IMHO wrong approach, just providing different icons, as can be seen from Gale’s link.
Please feel free to post a patch against the current svn head source. I’ll be happy to test it.
If you search the forum there were some posts (a long time ago) about theming. One user even posted a template that identified most of the colour maps.
Just my two cent on this: Enabling users to change the waveform or spectogram background would indeed be very useful!
Currently, you only have a choice between a colored spectrogram view that hurts your eyes and is not really well graded, and something a little more professional with a grayscale, but considering that the background is grey anyway, it suggests that there is a baseline uniform noise on all frequencies and makes the spectrogram less contrasty and difficult to see.
If you enabled us to have a white background, you would have better access to a new user-base of bioacoustics researchers which still have to rely on unpractical freeware or expensive commercial programs to generate their spectrograms. And a number of them would be developers maybe…
I’ll add a couple of votes to our Feature Request system.
Note that you can change the waveform colours including the background now, if you download one of the theme images from http://jcsu.jesus.cam.ac.uk/~hdc21/design/audacity/ , modify it, then follow the instructions on that page to add the image file to the Audacity folder for program data than edit audacity.cfg. If you get all the themes and compare them, you can probably figure which of the colour squares at the bottom you need to change.
Gale