invert_rgba
Tcl_Obj* imageObj

crimp_image* image;
crimp_image* result;
int          x, y;

crimp_input (imageObj, image, rgba);

result = crimp_new_like (image);

for (y = 0; y < image->h; y++) {
    for (x = 0; x < image->w; x++) {

	/*
	 * We are inverting (only) the color channels.
	 * The alpha channel is copied as is.
	 */

	R (result, x, y) = WHITE - R (image, x, y);
	G (result, x, y) = WHITE - G (image, x, y);
	B (result, x, y) = WHITE - B (image, x, y);

	A (result, x, y) = A (image, x, y);
    }
}

Tcl_SetObjResult(interp, crimp_new_image_obj (result));
return TCL_OK;


/* vim: set sts=4 sw=4 tw=80 et ft=c: */
/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 4
 * fill-column: 78
 * End:
 */