Re: [gtk-list] Re: drawing pixel ??

[Brandon Long <blong fiction net>]

On 10/10/98 Francisco Cespedes Moreno uttered the following other thing:
> 
> Brandon, to much thanks for your help, and sorry for my English, I'm
> Spanish.
> 
> Well, now I can draw pixels, but how can I define his color?
> 
> I must do for my University a program who read a pic, and apply to it
> filters. I think that I could do it draw pixel to pixel in a window. But I
> don know how to change this:
> > 
> > da = gtk_drawing_area_new ();
> > gtk_drawing_area_size (GTK_DRAWING_AREA (da), 50, 50);
> > gtk_container_add (GTK_CONTAINER (window), da);
> > gtk_realize_widget (da);
> > gdk_draw_point (da->window, da->style->black_gc, 10, 10);
> 				^
> 				|
> 			 THAT IS THIS
> > 
> How can I change this option, because I think that the color, doesn't it?

That is a Graphics Context, which contains various information about how
to draw, including foreground and background color.  You can use the
routine below to allocate a GC for a specific color, or else use the
gdk_color_alloc() function along with the gdk_gc_set_foreground() to
change the graphics context color.  If you do that, I suggest using
gdk_gc_copy() on black_gc and changing the color on the resulting GC.

Brandon

On 09/25/98 Eric Harlow uttered the following other thing:
> I wrote a routine called GetPen which returns a GdkGC* based on
> information I got within the last week which was quite helpful.  
> 
> Once I get my "pen", I use it all over the place.
> 
> 
> 
> GdkGC *GetPen (int red, int green, int blue)
> {
>     GdkColor *c;
>     GdkGC *gc;
> 
>     c = (gdkColor *) g_malloc (sizeof (GdkColor));
>     c->red = red;
>     c->blue = blue;
>     c->green = green;
> 
>     gdk_color_alloc (gdk_colormap_get_system (), c);
>     
>     // --- Use background pixmap HERE
>     gc = gdk_gc_new (pixmap);
>     
>     gdk_gc_set_foreground (gc, c);
> 
>     return (gc);
> }


-- 
 Brandon Long          "If organized religion is the opium of the masses,
 MD6 Crash Test Dummy   then disorganized religion is the marijuana of the
 Intel Corporation      lunatic fringe." -- Kerry Thornley, "Principia"
          I'm too low on the totem pole to speak for Intel.
		  http://www.fiction.net/blong/