static int
TIFFWriteTransferFunction(TIFF* tif, TIFFDirEntry* dir)
{
TIFFDirectory* td = &tif->tif_dir;
tsize_t n = (1L<<td->td_bitspersample) * sizeof (uint16);
uint16** tf = td->td_transferfunction;
int ncols;
/*
* Check if the table can be written as a single column,
* or if it must be written as 3 columns. Note that we
* write a 3-column tag if there are 2 samples/pixel and
* a single column of data won't suffice--hmm.
*/
switch (td->td_samplesperpixel - td->td_extrasamples) {
default:
if (_TIFFmemcmp(tf[0], tf[2], n)) {
ncols = 3;
break;
}
case 2:
if (_TIFFmemcmp(tf[0], tf[1], n)) {
ncols = 3;
break;
}
case 1:
case 0:
ncols = 1;
}
return (TIFFWriteShortTable(tif,
TIFFTAG_TRANSFERFUNCTION, dir, ncols, tf));
}
static tileContigRoutine
initYCbCrConversion(TIFFRGBAImage* img)
{
uint16 hs, vs;
if (img->ycbcr == NULL) {
img->ycbcr = (TIFFYCbCrToRGB*) _TIFFmalloc(
TIFFroundup(sizeof (TIFFYCbCrToRGB), sizeof (long))
+ 4*256*sizeof (TIFFRGBValue)
+ 2*256*sizeof (int)
+ 2*256*sizeof (int32)
);
if (img->ycbcr == NULL) {
TIFFError(TIFFFileName(img->tif),
"No space for YCbCr->RGB conversion state");
return (NULL);
}
TIFFYCbCrToRGBInit(img->ycbcr, img->tif);
} else {
float* coeffs;
TIFFGetFieldDefaulted(img->tif, TIFFTAG_YCBCRCOEFFICIENTS, &coeffs);
if (_TIFFmemcmp(coeffs, img->ycbcr->coeffs, 3*sizeof (float)) != 0)
TIFFYCbCrToRGBInit(img->ycbcr, img->tif);
}
/*
* The 6.0 spec says that subsampling must be
* one of 1, 2, or 4, and that vertical subsampling
* must always be <= horizontal subsampling; so
* there are only a few possibilities and we just
* enumerate the cases.
*/
TIFFGetFieldDefaulted(img->tif, TIFFTAG_YCBCRSUBSAMPLING, &hs, &vs);
switch ((hs<<4)|vs) {
case 0x44: return (putcontig8bitYCbCr44tile);
case 0x42: return (putcontig8bitYCbCr42tile);
case 0x41: return (putcontig8bitYCbCr41tile);
case 0x22: return (putcontig8bitYCbCr22tile);
case 0x21: return (putcontig8bitYCbCr21tile);
case 0x11: return (putcontig8bitYCbCr11tile);
}
return (NULL);
}
