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#define S(a) ((DOWNSCALE_SUM)(a))
void
DOWNSCALE_FUNCNAME (gint bpp,
gint src_width,
gint src_height,
guchar *src_data,
gint src_rowstride,
guchar *dst_data,
gint dst_rowstride)
{
gint y;
gint diag = src_rowstride + bpp;
const gint components = bpp / sizeof(DOWNSCALE_TYPE);
if (!src_data || !dst_data)
return;
switch (components)
{
case 1:
for (y = 0; y < src_height / 2; y++)
{
gint x;
guchar *src = src_data + src_rowstride * y * 2;
guchar *dst = dst_data + dst_rowstride * y;
for (x = 0; x < src_width / 2; x++)
{
DOWNSCALE_TYPE * aa = ((DOWNSCALE_TYPE *)(src));
DOWNSCALE_TYPE * ab = ((DOWNSCALE_TYPE *)(src + bpp));
DOWNSCALE_TYPE * ba = ((DOWNSCALE_TYPE *)(src + src_rowstride));
DOWNSCALE_TYPE * bb = ((DOWNSCALE_TYPE *)(src + diag));
((DOWNSCALE_TYPE *)dst)[0] = (S(aa[0]) + S(ab[0]) + S(ba[0]) + S(bb[0])) / DOWNSCALE_DIVISOR;
dst += bpp;
src += bpp * 2;
}
}
break;
case 2:
for (y = 0; y < src_height / 2; y++)
{
gint x;
guchar *src = src_data + src_rowstride * y * 2;
guchar *dst = dst_data + dst_rowstride * y;
for (x = 0; x < src_width / 2; x++)
{
DOWNSCALE_TYPE * aa = ((DOWNSCALE_TYPE *)(src));
DOWNSCALE_TYPE * ab = ((DOWNSCALE_TYPE *)(src + bpp));
DOWNSCALE_TYPE * ba = ((DOWNSCALE_TYPE *)(src + src_rowstride));
DOWNSCALE_TYPE * bb = ((DOWNSCALE_TYPE *)(src + diag));
((DOWNSCALE_TYPE *)dst)[0] = (S(aa[0]) + S(ab[0]) + S(ba[0]) +
S(bb[0])) / DOWNSCALE_DIVISOR;
((DOWNSCALE_TYPE *)dst)[1] = (S(aa[1]) + S(ab[1]) + S(ba[1]) +
S(bb[1])) / DOWNSCALE_DIVISOR;
dst += bpp;
src += bpp * 2;
}
}
break;
case 3:
for (y = 0; y < src_height / 2; y++)
{
gint x;
guchar *src = src_data + src_rowstride * y * 2;
guchar *dst = dst_data + dst_rowstride * y;
for (x = 0; x < src_width / 2; x++)
{
DOWNSCALE_TYPE * aa = ((DOWNSCALE_TYPE *)(src));
DOWNSCALE_TYPE * ab = ((DOWNSCALE_TYPE *)(src + bpp));
DOWNSCALE_TYPE * ba = ((DOWNSCALE_TYPE *)(src + src_rowstride));
DOWNSCALE_TYPE * bb = ((DOWNSCALE_TYPE *)(src + diag));
((DOWNSCALE_TYPE *)dst)[0] =
(S(aa[0]) + S(ab[0]) + S(ba[0]) + S(bb[0])) / DOWNSCALE_DIVISOR;
((DOWNSCALE_TYPE *)dst)[1] =
(S(aa[1]) + S(ab[1]) + S(ba[1]) + S(bb[1])) / DOWNSCALE_DIVISOR;
((DOWNSCALE_TYPE *)dst)[2] =
(S(aa[2]) + S(ab[2]) + S(ba[2]) + S(bb[2])) / DOWNSCALE_DIVISOR;
dst += bpp;
src += bpp * 2;
}
}
break;
case 4:
for (y = 0; y < src_height / 2; y++)
{
gint x;
guchar *src = src_data + src_rowstride * y * 2;
guchar *dst = dst_data + dst_rowstride * y;
for (x = 0; x < src_width / 2; x++)
{
DOWNSCALE_TYPE * aa = ((DOWNSCALE_TYPE *)(src));
DOWNSCALE_TYPE * ab = ((DOWNSCALE_TYPE *)(src + bpp));
DOWNSCALE_TYPE * ba = ((DOWNSCALE_TYPE *)(src + src_rowstride));
DOWNSCALE_TYPE * bb = ((DOWNSCALE_TYPE *)(src + diag));
((DOWNSCALE_TYPE *)dst)[0] =
(S(aa[0]) + S(ab[0]) + S(ba[0]) + S(bb[0])) / DOWNSCALE_DIVISOR;
((DOWNSCALE_TYPE *)dst)[1] =
(S(aa[1]) + S(ab[1]) + S(ba[1]) + S(bb[1])) / DOWNSCALE_DIVISOR;
((DOWNSCALE_TYPE *)dst)[2] =
(S(aa[2]) + S(ab[2]) + S(ba[2]) + S(bb[2])) / DOWNSCALE_DIVISOR;
((DOWNSCALE_TYPE *)dst)[3] =
(S(aa[3]) + S(ab[3]) + S(ba[3]) + S(bb[3])) / DOWNSCALE_DIVISOR;
dst += bpp;
src += bpp * 2;
}
}
break;
default:
for (y = 0; y < src_height / 2; y++)
{
gint x;
guchar *src = src_data + src_rowstride * y * 2;
guchar *dst = dst_data + dst_rowstride * y;
for (x = 0; x < src_width / 2; x++)
{
gint i;
DOWNSCALE_TYPE * aa = ((DOWNSCALE_TYPE *)(src));
DOWNSCALE_TYPE * ab = ((DOWNSCALE_TYPE *)(src + bpp));
DOWNSCALE_TYPE * ba = ((DOWNSCALE_TYPE *)(src + src_rowstride));
DOWNSCALE_TYPE * bb = ((DOWNSCALE_TYPE *)(src + diag));
for (i = 0; i < components; i++)
((DOWNSCALE_TYPE *)dst)[i] =
(S(aa[i]) + S(ab[i]) + S(ba[i]) + S(bb[i]))/DOWNSCALE_DIVISOR;
dst += bpp;
src += bpp * 2;
}
}
break;
}
}
#undef S
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