Re: GC foreground color.

[Owen Taylor <otaylor redhat com>]

On Wed, 2003-06-25 at 04:48, Deganello Aligi wrote:
>   Hi all, I want to draw a red line on a drawing area but it seem not
> possible to chage the foreground color. I can't understand why I can modify
> the line attributes but not the color. Can someone help me. I'm virgin new
> user of GTK.
> Here is the code. What's wrong?
>
> static gint expose_event (GtkWidget *widget, GdkEventExpose *event)
> {
>       GdkGC           *gc;
>       GdkColor        *color;
>
>       gc=gdk_gc_new(widget->window);
>       color = g_malloc(sizeof(GdkColor));
>       color->red = 0xffff; color->green = 0x0; color->blue = 0x0;
>       gdk_gc_set_foreground(gc, color);

A) No reason to malloc the color here. Just allocate it on the 
stack:

 GdkColor red = { 0, 0xffff, 0, 0 };

B) gdk_gc_set_foreground() takes an allocated color. You'd need
   to use gdk_colormap_alloc_color() first. But easier, use
   gdk_gc_set_rgb_fg_color() which does the allocation for you.

     gdk_gc_set_rgb_fg_color (gc, &red);

Regards,
                                Owen