Oops - I missed out some vital pixel region initialisation.
On Friday, 6 Apr 2001, Austin Donnelly wrote:
> gimp_drawable_mask_bounds (drawable->id, &x1, &y1, &x2, &y2);
>
> for (y = y1; y < y2; y += tile_width - (y % tile_width))
> {
> for (x = x1; x < x2; x += tile_width - (x % tile_width))
> {
/* set up the source and dest regions */
gimp_pixel_rgn_init (&src_rgn, drawable, x, y, x_step, y_step,
FALSE/*dirty*/, FALSE/*shadow*/);
gimp_pixel_rgn_init (&dest_rgn, drawable, x, y, x_step, y_step,
TRUE/*dirty*/, TRUE/*shadow*/);
> /* process the image in tile-sized regions */
> for (pr = gimp_pixel_rgns_register (2, &src_rgn, &dest_rgn);
> pr != NULL;
> pr = gimp_pixel_rgns_process (pr))
> {
> src_row = src_rgn.data;
> dest_row = dest_rgn.data;
>
> for (row = 0; row < src_rgn.h; row++)
> {
> src = src_row;
> dest = dest_row;
>
> for (col = 0; col < src_rgn.w; col++)
> {
>
> /* do stuff with src[0..bpp] and dest[0..bpp] */
>
> src += src_rgn.bpp;
> dest += dest_rgn.bpp;
> }
>
> src_row += src_rgn.rowstride;
> dest_row += dest_rgn.rowstride;
> }
> }
> }
> }
