Re: How to use the GdkColor.pixel

[Russell Shaw <rjshaw iprimus com au>]

Owen Taylor wrote:
> On Thu, 2003-12-11 at 12:14, Tom Liu wrote:
>
> > Thanks!, I understand now. 
> >
> > But, how to get the rgb value of a allocated color? In my application, I
> > allocated a lot of color when I start program, should I use RGB value?
>
> I'd just use RGB values and let GTK+ worry about allocating them,
> normally. (gdk_colormap_query_color() can be used to find the RGB
> of an allocated color.)
>
> > How about for performance?  Every time to use GdkColor in GTK+,
> > internally it need to go alloc the color, will this slow down?
>
> On any modern display (TrueColor), gdk_colormap_alloc_color() 
> is really fast - it's just a few bitshifts.
>
> But even on older pseudo-color displays, letting GTK+ allocate
> the color will generally be quite fast enough ... if the color is
> already in use, it can find it without having to ask the X server to
> allocate a new color.

IIRC, pseudo color goes thru a colormap table, so you can change
a displayed color by changing its table entry instead of having to
redraw. Can most X servers be assumed to have pseudo color?