Re: Drawing area color weirdness help?

[Owen Taylor <otaylor redhat com>]

"Andrew P. Lentvorski" <andrewl@deliverator.io.com> writes:

> Okay, I created a set of widgets and packed everything together.
> One of the widgets is a GtlDrawingArea.  Fine.  I attach the expose
> event to the callback function at the bottom of this message.
> Everything comes up fine.  It even creates a nice red rectangle.
> Then I resize the window ... urp ... the color in the GtlDrawingArea
> changes to a random color every time I resize it.  Yellow .. Green ...
> Blue ... you name it.  No particular rhyme or reason.
> 
> Why?
> 
> I'm assuming that I'm doing something wrong, but I have no idea what.
> 
> Also, how do you create a GdkColor from an RGB value?
> 
> Thanks,
> Andy Lentvorski
> 
> Expose callback function starts here:
> static gint
> wave_expose_event(GtkWidget *widget, GdkEventExpose *event)
> {
>   gint width,height;
>   GdkColor foreground;
>   GdkGC *mygc;
> 
>   if (!gdk_color_parse("red",&foreground))
>     {
>       fprintf(stderr,"Failed to parse color\n");
>     }
> 
>   gdk_window_get_size(widget->window,&width,&height);
> 
>   if (!(mygc = gdk_gc_new(widget->window)))
>     {
>       fprintf(stderr,"Failed to allocate GC\n");
>     }
> 
>   gdk_gc_set_foreground(mygc,&foreground);

gdk_color_parse() does not allocate the color, it just
fills in the .red .green and .blue fields. It is 
a coincidence you got Red the first time. 
The values for red, green and blue range from
0-65535.

To use a color, you must first fill in the red,
green and blue fields, then call gdk_color_alloc().
(You probably don't want to parse and allocate the color
on each expose event though - best to do that only
once.)

I think that should answer your other question as well.

Regards,
                                        Owen