int
icv_resize(icv_image_t *bif, ICV_RESIZE_METHOD method, unsigned int out_width, unsigned int out_height, unsigned int factor)
{
ICV_IMAGE_VAL_INT(bif);
switch (method) {
case ICV_RESIZE_UNDERSAMPLE :
return under_sample(bif, factor);
case ICV_RESIZE_SHRINK :
return shrink_image(bif, factor);
case ICV_RESIZE_NINTERP :
return ninterp(bif, out_width, out_height);
case ICV_RESIZE_BINTERP :
return binterp(bif, out_width, out_height);
default :
bu_log("icv_resize : Invalid Option to resize");
return -1;
}
}
/*
* Scale a file of pixels to a different size.
*
* To scale down we make a square pixel assumption.
* We will preserve the amount of light energy per unit area.
* To scale up we use bilinear interpolation.
*/
int
scale(FILE *ofp, int ix, int iy, int ox, int oy)
{
int i, j, k, l;
double pxlen, pylen; /* # old pixels per new pixel */
double xstart, xend, ystart, yend; /* edges of new pixel in old coordinates */
double xdist, ydist; /* length of new pixel sides in old coord */
double sum;
unsigned char *op;
pxlen = (double)ix / (double)ox;
pylen = (double)iy / (double)oy;
if ((pxlen < 1.0 && pylen > 1.0) || (pxlen > 1.0 && pylen < 1.0)) {
fprintf(stderr, "bwscale: can't stretch one way and compress another!\n");
return -1;
}
if (pxlen < 1.0 || pylen < 1.0) {
/* scale up */
if (rflag) {
/* nearest neighbor interpolate */
ninterp(ofp, ix, iy, ox, oy);
} else {
/* bilinear interpolate */
binterp(ofp, ix, iy, ox, oy);
}
return 0;
}
/* for each output pixel */
for (j = 0; j < oy; j++) {
size_t ret;
ystart = j * pylen;
yend = ystart + pylen;
op = outbuf;
for (i = 0; i < ox; i++) {
xstart = i * pxlen;
xend = xstart + pxlen;
sum = 0.0;
/*
* For each pixel of the original falling
* inside this new pixel.
*/
for (l = FLOOR(ystart); l < CEILING(yend); l++) {
/* Make sure we have this row in the buffer */
bufy = l - buf_start;
if (bufy < 0 || bufy >= buflines) {
fill_buffer(l);
bufy = l - buf_start;
}
/* Compute height of this row */
if ((double)l < ystart)
ydist = CEILING(ystart) - ystart;
else
ydist = MIN(1.0, yend - (double)l);
for (k = FLOOR(xstart); k < CEILING(xend); k++) {
/* Compute width of column */
if ((double)k < xstart)
xdist = CEILING(xstart) - xstart;
else
xdist = MIN(1.0, xend - (double)k);
/* Add this pixels contribution */
/* sum += old[l][k] * xdist * ydist; */
sum += buffer[bufy * scanlen + k] * xdist * ydist;
}
}
*op++ = (int)(sum / (pxlen * pylen));
if (op > (outbuf+scanlen))
bu_bomb("unexpected buffer overrun");
}
ret = fwrite(outbuf, 1, ox, ofp);
if (ret != (size_t)ox)
perror("fwrite");
}
return 1;
}
