Re: [gtk-list] Re: Displaying images from a camera as fast as possible?/RGB images

[john giorgio hart bbk ac uk]

Nils Hulth <Nils.Hulth@lucs.lu.se> wrote:
>What I'm really after is a widget where I can manipulate the RGB-values
>directly, and do memory copies of large chunks, and afterwards flush the
>whole picture onto the screen. The best would be if I could reuse the same
>memory again, to avoid slow copies. 

The absolute fastest way AFAIK is to call gdk_draw_rgb_image() directly. Take
a look at gtk/testrgb.c, you should be able to get 10 mpixels/sec on a nice
PC. I use this in my image display program with good results.

>I do not like the using the DGA extension
>since you need to be root to use it, therefore I can accept some slowdown. Is
>there such a thing?

gdk_draw_rgb_image() uses shared memory (via Xshm) if possible, so it gets you
much the same order of speed up, but without needing that DGA stuff.

Good luck,

John
--
John Cupitt, john.cupitt@ng-london.org.uk, +44 (0)171 930 2108
VASARI Lab, The National Gallery, Trafalgar Square, London, WC2N 5DN