// Modify capture window (if necessary)
// and calculate downscaling
// Return -1 on error
static int w9966_calcscale(int size, int min, int max, int* beg, int* end, unsigned char* factor)
{
int maxlen = max - min;
int len = *end - *beg + 1;
int newlen = w9966_findlen(len, size, maxlen);
int err = newlen - len;
// Check for bad format
if (newlen > maxlen || newlen < size)
return -1;
// Set factor (6 bit fixed)
*factor = (64*size) / newlen;
if (*factor == 64)
*factor = 0x00; // downscale is disabled
else
*factor |= 0x80; // set downscale-enable bit
// Modify old beginning and end
*beg -= err / 2;
*end += err - (err / 2);
// Move window if outside borders
if (*beg < min) {
*end += min - *beg;
*beg += min - *beg;
}
if (*end > max) {
*beg -= *end - max;
*end -= *end - max;
}
return 0;
}
static int w9966_calcscale(int size, int min, int max, int* beg, int* end, unsigned char* factor)
{
int maxlen = max - min;
int len = *end - *beg + 1;
int newlen = w9966_findlen(len, size, maxlen);
int err = newlen - len;
if (newlen > maxlen || newlen < size)
return -1;
*factor = (64*size) / newlen;
if (*factor == 64)
*factor = 0x00;
else
*factor |= 0x80;
*beg -= err / 2;
*end += err - (err / 2);
if (*beg < min) {
*end += min - *beg;
*beg += min - *beg;
}
if (*end > max) {
*beg -= *end - max;
*end -= *end - max;
}
return 0;
}