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/* scale image from SRC to DST - parameterized by type T */
/* get pixel address of point (x,y) in image t */
#define getP(t,x,y) \
(T *) (&ximage[t]->data[(ximage[t]->xoffset+(x))*sizeof(T) + \
(y)*ximage[t]->bytes_per_line])
{
int i, j, k;
/* copy scaled lines from SRC to DST */
j = flipxy ? width[SRC] - 1 : height[SRC] - 1;
do {
T *p1;
T *p2;
int p2step;
T *p1_save;
/* p1 point to begining of scanline j*magy in DST */
p1 = getP(DST,0,j*magy);
p1_save = p1;
/* p2 point to begining of scanline j in SRC */
/* if flipy then line height[SRC]-1-j */
p2 = getP(SRC,0,flipy ? (height[SRC]-1-j) : j);
if (flipxy)
{
p2 = getP(SRC,flipy ? j : (width[SRC]-1-j),0);
p2step = ximage[SRC]->bytes_per_line / sizeof(T);
if (flipx)
{
p2 += p2step * (height[SRC]-1);
p2step = -p2step;
}
i = height[SRC];
do {
T c = *p2; p2 += p2step;
k = magx; do *p1++ = c; while (--k > 0);
} while (--i > 0);
}
else if (flipx)
{
p2 += width[SRC];
i = width[SRC];
do {
T c = *--p2;
k = magx; do *p1++ = c; while (--k > 0);
} while (--i > 0);
}
else
{
i = width[SRC];
do {
T c = *p2++;
k = magx; do *p1++ = c; while (--k > 0);
} while (--i > 0);
}
/* draw vertical grid */
if (gridy && magx >= 2)
{
p1 = p1_save - 1;
i = magx;
k = flipxy ? height[SRC] : width[SRC];
do {
p1 += i;
*p1 ^= ~((T)0);
} while (--k > 0);
}
/* duplicate that line as needed */
if (magy > 1)
{
/* p1 point to begining of scanline j*magy in DST */
p1 = p1_save;
/* p2 points to begining of next line */
p2 = p1;
p2step = ximage[DST]->bytes_per_line / sizeof(T);
i = width[DST] * sizeof(T);
k = magy - 1;
do {
p2 += p2step;
memcpy(p2, p1, i);
} while (--k > 0);
/* draw horizontal grid */
if (gridx && magy >= 2)
{
k = width[DST];
do {
*p2++ ^= ~((T)0);
} while (--k > 0);
}
}
} while (--j >= 0);
}
#undef getP
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