Re: question: colors, visuals, please help to understand

[Olexiy Avramchenko <ath beast stu cn ua>]

Alexander Chemeris wrote:

> Thursday, August 22, 2002, 3:34:15 PM, you wrote:
>
> > Alexander Chemeris wrote:
>
> > > Tuesday, August 20, 2002, 2:37:25 PM, you wrote:
> > >
> > > >  I need to allocate colors in PseudoColor and change their values
> > > > in runtime (gtk+-2.0). GDK allows me to allocate a writeable colors
> > > > in colormap via gdk_colormap_alloc_colors. But the problem is all
> > > > functions I've found are deprecated: gdk_colors_store,
> > > > gdk_color_change, gdk_colormap_change.
> > > See for GdkRGB part of Gdk.
> > There's no direct support for writeable colours in GdkRGB.
> >
> > > Function used to allocate colors here is gdk_rgb_find_color().
> > Allocate - yes, but not to change the value of previously allocated
> > writeable colour. I need to have a constant pixel value (initialized
> > by gdk_colormap_alloc_colors in startup time) and ability to change
> > the R/G/B values of this pixel. I can't find non-deprecated
> > functions to do this - that's the main reason of my screams.
> Hmm, why do you need writable colors?
Cause I'm using PseudoColor mode and I need to change the colours values in
runtime without frame recalculation (cause of performance reasons).

> May be cmaps would help you?
> See gdk_rgb_cmap_new()/gdk_rgb_cmap_free() and gdk_draw_indexed_image()
> There isn't much documentation, but I think it all you need:
> Allocate cmap, fill it with your colors, and then, when you need to
> change color use something like this:
> your_cmap->colors[color_number] = (r<<16) | (g<<8) | b;
This's ok for the gdk rgb, but it's not acceptable for me cause of 
performance
reasons. It's better/simple/faster to use TrueColor directly than draw 
indexed
gdk rgb into drawables.

> I never deal with this, but I saw at the gdk_rgb_indexed_to_stage()
> function implementation in gdkrgb.c... ;-)
> I think you must dig in the gdkrgb code and when you find appropriate
> way - document it. ;-)
All I want - just to know has gtk+-2.0 non-deprecated writeable colours 
support
or no.

Olexiy