Re: Question about the GdkGC

[Tristan Van Berkom <vantr touchtunes com>]

Tom Liu wrote:

> When I create a GdkGC, I have to give a GdkDrawable to attach this GC,
> But when I draw line or rectangle, I still need the GdkDrawable as
> parameter.
You need to provide a GdkDrawable so that the GdkGC can reference a
colormap; the colormap is created when you create a GdkDrawable
and; if I'm not mistaken; thats because creating the colormap requires
some knowlage of the rendering architechture (Win or XFree86)
(and thats handled at the GdkDrawable level).

> Is these because one GdkGC can work on multile GdkDrawable after it
> created?
>  
Yes it can.

> Another question: the CreateGC and releaseGC is a expensive job? Should
> I create and release it every time I need to draw or just keep a global
> copy for better performance.
>  
A GdkGC is like a structure that holds a bunch of paramaters
to draw with when using any GdkDrawables; instead of passing
alot of arguments to the drawing functions; the arguments that
probably won't change from one function call to the next; are
stored in the graphics context.

Does that help ?

Regards,
                                               -Tristan

--
"Life would be so much easier if we could just look at the source code."
        -- Francois Baumier