Re: How to use the GdkColor.pixel

[Owen Taylor <otaylor redhat com>]

On Thu, 2003-12-11 at 11:02, Tom Liu wrote:
> I use the gdk_color_alloc to get the pixel for a color. 
> When I use the pixel to set the color, it doesn't work, 
> When I just set red,green,blue, it will work.
>
>         GdkColormap* sysmap=gdk_colormap_get_system();
>         GdkColor color;
>         if (gdk_color_parse   ("#FF0000",&color)) {
>                 gdk_color_alloc (sysmap,&color) ;
>         }
>         color.red=0;color.blue=0;color.green=0;
>         printf("color:%d\n",color.pixel);
>         gtk_widget_modify_bg(widg,GTK_STATE_NORMAL,&color);
>
> looks color.pixel is useless, is that true?

General rule (with a few exceptions is):

 GTK+ functions take unallocated colors
 GDK functions take allocated colors 

An unallocated color means that the 'pixel' field is unused
and will be determined by GTK+.

E.g., the docs for gtk_widget_modify_bg say:

 * @color: the color to assign (does not need to be allocated),
 *         or %NULL to undo the effect of previous calls to
 *         of gtk_widget_modify_bg().

Regards,
                                                Owen