expand_grey8_replicate
Tcl_Obj* imageObj
int ww
int hn
int we
int hs

/*
 * Border expansion by extending the edges, i.e. replicating the border
 * pixels.
 */

crimp_image* image;
crimp_input (imageObj, image, grey8);

/*
 * This is the simple definition. Might be better to generate macros
 * specialized to each quadrant. Except, even they have to perform modulo
 * arithmetic, as the border may be larger than image's width or height,
 * causing muliple wrapping.
 */

#define FILL(xo,yo) {					\
	int xi = xo - ww;				\
	int yi = yo - hn;				\
	if      (xi < 0)         { xi = 0;            } \
	else if (xi >= image->w) { xi = (image->w-1); } \
							\
	if      (yi < 0)         { yi = 0;            } \
	else if (yi >= image->h) { yi = (image->h-1); } \
							\
	GREY8 (result, xo, yo) = GREY8 (image, xi, yi);	\
    }

#define COPY(xo,yo,xi,yi) {				\
	GREY8 (result, xo, yo) = GREY8 (image, xi, yi); \
    }

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