Re: [gtk-list] what is the pixel value of the GdkColor ?

[Sven LUTHER <luther maxime u-strasbg fr>]

On Wed, May 26, 1999 at 04:29:06PM +0200, Stefan Ondrejicka wrote:
> On Wed, 26 May 1999, Sven LUTHER wrote:
> 
> 
> Hi !
> 
> > What is contained in the pixel value of the Gdkcolor type ?
> 
> It is pointer to color inside colormap. So you don't need to fill it. It
> is automaticaly filled when you call gdk_colormap_alloc_color() function.

Ok, that is what i guessed ...

> 
> [...]
> 
> > /* is it necessary to put the color in a colrmap, or could i do without it ? */
> 
> Yes, if you want to do something with colors inside X, you need at first
> allocate pixel in colormap.
> 
> > colormap = gdk_window_get_colormap ((GdkWindow *)pixmap) ;
> >  /* what is the meaning of writeable and best_match ? */
> > gdk_colormap_alloc_color (colormap, &color, writeable, best_match);
> 
> [...]
> 
> > Later when i want ot retrieve the color associated with a pixel of the pixmap,
> > do i do :
> > ----------------------------------------
> > image = gdk_image_get ((GdkWindow *)pixmap, 0, 0, x+1, y+1);
> > pixel = get_image_get_pixel (image, x, y);
> > ----------------------------------------
> > 
> > how can i get back to the GdkColor value associated with said pixel.
> 
> easy way, how to do it :
> 
> 	color = colormap->colors[pixel];
> 
> But, I hope that, there should be some function for it.

In my case, i am writting a binding for ocaml, an ml style language and what
you just described is quite un-nice. a :

Gdkcolor gdk_colormap_get_pixel_color (GdkColormap colormap, gunit32 pixel)

would be very nice,

Friendly,

Sven LUTHER