On Wed, 2003-02-19 at 17:34, Juan Pablo wrote:
Hi I have been folowing the thread, and all i can do is post what i know, wich is not the last word, of course... There is two kind of "visuals", truecolor and indexed (indexed are out of the scope) BPP R G B A 15 5 5 5 0 16 5 6 5 0 24 8 8 8 0 32 8 8 8 8 Actualy 32bpp is not a visual, alpha channel is used into the program or if the hardware have acceleration for overlay, etc... but there is no alpha structure in X. Human eye can distinguish more luma(grayscale) than croma(colors), that is why, when the light is very low we start to see in grayscale. Because we have more luma receptors than croma (don know the name in
rods and cones. iirc cones are the receptors for colour, and rods are for b&w Of course.. that could be the opposite way around.. but I got a 50% chance of being right ;)
english :). This fact was used long ago by the people who invent the TV signal. NTSC for example, it uses YUV or YIQ (is is the same for this pourpose) half brandwidght for Y (luma) and the other half for UV. MPEG and its derivates like JPEG uses the same principle (see subsampling 2:1:1, 4:2:2 etc) So i do not recomend using a jpg to store cientific data, instead BMP is so basic that there is no way to loose data (tiff can be saved as jpeg:) So i recommend you to use all the bits you want per pixel in an internal data structure (array) and then shift to 8bpp to display it :) chau Juan Pablo http://xjuan.gq.nu _______________________________________________ gtk-app-devel-list mailing list gtk-app-devel-list gnome org http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
--
Azrael
("\''/").___..--'''"-._
`0_ O ) `-. ( ).`-.__.`)
(_Y_.)' ._ ) `._ `. ``-..-'
_..`--'_..-_/ /--'_.' .'
((i).-'' ((i).' (((.-'
Of all God's creatures there is only one that cannot be made the slave
of the lash. That one is the cat. If man could be crossed with a cat it
would improve man, but it would deteriorate the cat.
ICQ#52944566
Registered Linux User: 269002
Attachment:
signature.asc
Description: This is a digitally signed message part