Re: [gtk-list] Re: clip origin, and **clip mask origion** ??

[Travis Loyd <lelandg usa net>]

On Fri, 14 May 1999, Paul Barton-Davis wrote:

> >
> >HOW DO YOU CREATE A MASK FOR EACH ONE!!!!!!!!!!!!!!! :)
> 
> Ah yes. Well, there is a way, although it rather ugly.
> 
> Create the composite pixmap. Create a GdkBitmap of the right size (any
> way you can think of). Create a GC with a depth of 2. Draw the
> relevant section into the bitmap with the GC. Voila.

I'm amazed with what I've created so far using GTK considering my lack of
fundamental understanding. I don't know what a GC actually is although
I've used them quite a bit. I don't know how to create a GC with a depth
of 2.

And if I don't have the mask yet doesn't it make sense that when I draw
the mask that it will copy a square because in order to copy we need to
already have the mask?

I'm trying to implement your suggesting and getting this error:

Gdk-ERROR **: BadMatch (invalid parameter attributes)
  serial 2192 error_code 8 request_code 62 minor_code 0

I don't know how to make a GC of 2, that might be the problem.

I've attached one of the functions I'm trying to do this in, but if you
know exactly what I'm asking I suspect you don't need it.

Could you please give an example. Later on I believe my program might be
well used as an example for future GTK programmers.


Travis Loyd
[email: lelandg@usa.net				Encrypt your email too: ]
[other: s201635@mail.nwmissouri.edu		     http://www.pgp.com	]
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void add_walls(struct reference_hold *sister) {
	gint x, y, z, ptr;
	GdkBitmap *the_mask;
	GdkGC *the_gc;

	the_mask = gdk_pixmap_new(sister->main_window->window, 40, 40, 1);
	the_gc = gdk_gc_new(sister->main_window->window);

	for(ptr = 0; ptr < sister->factory_tile_size; ptr ++) {
		if(sister->factory_tile_layout[ptr] == 0xd2) {
			for(++ptr;ptr < sister->factory_tile_size; ptr ++) {
				if(sister->factory_tile_layout[ptr] >= 0xd0) {
					/* We are out of walls */
//					ptr--;
					break;
				}

				x = sister->factory_tile_layout[ptr];
				y = sister->factory_tile_layout[++ptr];
				z = sister->factory_tile_layout[++ptr];

				/* This adds the walls */
				switch(z) {
					case 0:
						gdk_draw_pixmap(
							the_mask, the_gc,
							sister->tileset_xpm, WALL_NORTH_X, WALL_NORTH_Y,
							(x*TILE_SIZE), (y*TILE_SIZE), TILE_SIZE, TILE_SIZE);
						gdk_gc_set_clip_mask(sister->tileset_gc, the_mask);
//						my_set_gc_clip_mask(sister,
//							(WALL_NORTH_X), (WALL_NORTH_Y));
						gdk_gc_set_clip_origin(sister->tileset_gc,
							(x*TILE_SIZE), (y*TILE_SIZE));
						gdk_draw_pixmap(
							sister->factory_tile_xpm, sister->tileset_gc,
							sister->tileset_xpm, WALL_NORTH_X, WALL_NORTH_Y,
							(x*TILE_SIZE), (y*TILE_SIZE), TILE_SIZE, TILE_SIZE);
						break;
				}
			}
			break;
		}
	}
}