Ximtool & 24bit
Sergei O. Naoumov wrote on Sep 07, 1998
Hi! I was wondering how one deals with this problem of running ximtool on a 24-bit display. By the way, I am VERY curiouos why exactly the application was written in a such a way that it only runs on an 8 bit screen. Anyway, I have Ultra 10 running in a truecolor mode, and it seems VERY strange to switch it back into 8bit for a sole purpose of being able to run a single application. Thanks, Sergei
Mike Fitzpatrick wrote on Sep 08, 1998
Sergei Naoumov (serge@avarice.astro.unc.edu)writes: > I was wondering how one deals with this problem of running ximtool on > a 24-bit display. By the way, I am VERY curiouos why exactly the > application was written in a such a way that it only runs on an 8 bit > screen. When XImtool was first written, about 5-6 years ago, 24-bit displays were still only available on high end systems or specialized platforms such as SGI, most PCs in the world also lacked the video cards for 24-bit and Linux was still in it's early stages. Nowadays it's hard to buy a new system that doesn't have 24-bit support. It was always thought that 24-bit support would be added but it wasn't deemed a priority at the beginning when the Gterm widget was being written. The problem is not that it's difficult to display an image on a 24-bit screen, it's that unlike programs such as XV (which display a static image), Ximtool has too allow brightness/contrast stretching when viewing the image. This is currently done, for speed reasons, by recomputing and rewriting the colormap used to display the image (rather than redisplaying the image itself). However, in a 24-bit display there is no colormap so modifying the image to increase the contrast becomes non-trivial and more expensive. There are plans to make XImtool and the Gterm widget on which it relies work under a 24-bit display, this will be part of the x11iraf work in progress now, but I cannot give you a date for when this will be ready. For the moment the only solution is to use an 8-bit visual when using XImtool. There was an interesting discussion in this newsgroup a while back talking about various other strategies to work around this, you can access these via our search page at http://iraf.noao.edu/seach/searches.html#NEWSSEARCH The search term "16-bit" on the adass.iraf.system group will bring up the relevant articles. Cheers, -Mike
Last post on Sep 08, 1998