On Thu, Jul 04, 2002 at 03:31:46PM +0200, Simon Budig wrote:
>
> I should have read the code before posting my last message:
>
> Dr William Bland (wjb@xxxxxxxxxxxxxxxxxxxx) wrote:
> > I thought about using some kind of "double tile iterator" to do this, e.g:
> >
> > gimp_pixel_rgn_init (&image_rgn, image_drawable,
> > x1, y1, (x2 - x1), (y2 - y1), TRUE, TRUE);
> > gimp_pixel_rgn_init (&select_rgn, select_drawable,
> > x1, y1, (x2 - x1), (y2 - y1), TRUE, TRUE);
> > for (p1 = gimp_pixel_rgns_register (1, &image_rgn),
> > p2 = gimp_pixel_rgns_register (1, &select_rgn);
> > (p1 != NULL) && (p2 != NULL);
> > p1 = gimp_pixel_rgns_process (p1),
> > p2 = gimp_pixel_rgns_process (p2))
>
> this better should be
> p1 = gimp_pixel_rgns_register (2, &image_rgn, &select_rgn);
> p1 != NULL;
> p1 = gimp_pixel_rgns_process (p1)
>
> > {
> > /* Interesting stuff goes in here! */
> > /* Set some of the pixels in select_drawable */
> > /* depending on the pixels in image_drawable. */
> > }
>
> Then the core will care about the stuff I mentioned in the other mail.
Hi Simon,
Thanks! That looks much nicer. Unfortunately I can't get it to
work properly (sorry, like I said, I'm a newbie at this ;-). I now have
the following code:
static void
do_stuff (GimpDrawable *image_drawable, GimpDrawable *select_drawable)
{
GimpPixelRgn image_rgn, select_rgn;
gint x1=0, y1=0, x2=select_drawable->width, y2=select_drawable->height;
guchar *image_data = NULL, *select_data;
gint i;
gint image_bytes = image_drawable->bpp, select_bytes = select_drawable->bpp;
gint size;
gpointer pr;
gimp_pixel_rgn_init (&image_rgn, image_drawable, x1, y1,
(x2 - x1), (y2 - y1), TRUE, TRUE);
gimp_pixel_rgn_init (&select_rgn, select_drawable, x1, y1,
(x2 - x1), (y2 - y1), TRUE, TRUE);
for ( pr = gimp_pixel_rgns_register (2, &select_rgn, &image_rgn);
pr != NULL;
pr = gimp_pixel_rgns_process (pr))
{
size = select_rgn.w * select_rgn.h;
select_data = select_rgn.data;
while (size--)
{
for (i=0; i<select_bytes; i++)
*select_data++ = 255*(size%2);
}
}
/* merge the shadow, update the drawable */
gimp_drawable_flush (select_drawable);
gimp_drawable_merge_shadow (select_drawable->id, TRUE);
gimp_drawable_update (select_drawable->id, x1, y1, (x2 - x1), (y2 - y1));
}
Note that I'm not yet actually *doing* anything with the data in
image_rgn, only select_rgn. Now if I start gimp, create a blank 256*256
image, select everything and then run my plugin, I get:
http://www.abstractnonsense.com/double.png
which is clearly not right! Some of the pixels are correct, but there is
clearly some random fluff in there as well.
If I change the iterator to a single one, so that it reads
for ( pr = gimp_pixel_rgns_register (1, &select_rgn);
then I get:
http://www.abstractnonsense.com/single.png
which is correct but doesn't help since I will be needing the double
iterator soon.
Any ideas what's going on here? Thanks again for your help.
Best wishes,
Bill.
