--- David Neèas (Yeti) <yeti@xxxxxxxxxxxxxxx> wrote: > > On Thu, Sep 27, 2007 at 04:45:10PM +0200, alex wrote: > > I want to create a grayscale image from a CCD camera. > > Data are from a function wich gives me an 16 bits array corresponding to > > the CCD's pixels. > > I take a look at the pixbuf class, but it seems to use a RGB structure. > > How can I do my job ? > > If you don't expect the graphics system to be actually > capable of displaying 16bpc images, it is easiest to just > convert the data to 8bpp RGB (which is a trivial operation). > > Yeti > > -- > http://gwyddion.net/ > _______________________________________________ > gtk-list mailing list > gtk-list@xxxxxxxxx > http://mail.gnome.org/mailman/listinfo/gtk-list > Oh, I expect a lot of things. And I do not consider a lot of things to be trivial. First of all, modern displays have contrast ratios greater than 255:1, so there is no physical reason not expect more than 8 bits of dynamic range, and, actually, even with smaller contrast ratios the matter is brighness resolution. Second, 16 -> 8 bits conversion is not trivial - I am not talking about taking just, say, upper 8 bits of a 16 bits word. I am talking about brightness compression first. For example, I can decide to use 12 bits of dynamic range of input image, then convert them to 8 bits using something gamma-like curve, i.e. mapping function, changing the curve steepness as needed for my image, for example, increasing it in lower values range if I want to show shadow details. ... Remember, KDE's KRITA uses ImageMagic for a reason; ImageMagic supports up to floating point number per color per pixel IIRC. Regards, Sergei. Applications From Scratch: http://appsfromscratch.berlios.de/ ____________________________________________________________________________________ Need a vacation? Get great deals to amazing places on Yahoo! Travel. http://travel.yahoo.com/ _______________________________________________ gtk-list mailing list gtk-list@xxxxxxxxx http://mail.gnome.org/mailman/listinfo/gtk-list
