static void
adaptRowFormat(struct pam * const inpamP,
struct pam * const outpamP,
tuple * const tuplerow) {
/*----------------------------------------------------------------------------
Convert the row in 'tuplerow', which is in a format described by
*inpamP, to the format described by *outpamP.
'tuplerow' must have enough allocated depth to do this.
-----------------------------------------------------------------------------*/
assert(outpamP->visual);
assert(inpamP->visual);
pnm_scaletuplerow(inpamP, tuplerow, tuplerow, outpamP->maxval);
if (outpamP->color_depth == 3) {
if (outpamP->have_opacity)
pnm_makerowrgba(inpamP, tuplerow);
else
pnm_makerowrgb(inpamP, tuplerow);
} else {
if (outpamP->have_opacity)
pnm_addopacityrow(inpamP, tuplerow);
}
}
static void
ditherImage(struct pam * const inpamP,
const scaler * const scalerP,
unsigned int const dithPower,
struct colorResolution const colorRes,
struct pam * const outpamP,
tuple *** const outTuplesP) {
unsigned int const dithDim = 1 << dithPower;
unsigned int const ditherMatrixArea = SQR(dithDim);
unsigned int const modMask = (dithDim - 1);
/* And this into N to compute N % dithDim cheaply, since we
know (though the compiler doesn't) that dithDim is a power of 2
*/
unsigned int ** const ditherMatrix = dithMatrix(dithPower);
tuple * inrow;
tuple ** outTuples;
unsigned int row;
struct pam ditherPam;
/* Describes the tuples that ditherRow() sees */
assert(dithPower < sizeof(unsigned int) * 8);
assert(UINT_MAX / dithDim >= dithDim);
validateNoDitherOverflow(ditherMatrixArea, inpamP, colorRes);
inrow = pnm_allocpamrow(inpamP);
outTuples = pnm_allocpamarray(outpamP);
/* We will modify the input to promote it to depth 3 */
ditherPam = *inpamP;
ditherPam.depth = 3;
for (row = 0; row < inpamP->height; ++row) {
pnm_readpamrow(inpamP, inrow);
pnm_makerowrgb(inpamP, inrow);
ditherRow(&ditherPam, inrow, scalerP, ditherMatrix, ditherMatrixArea,
colorRes, row, modMask,
outpamP, outTuples[row]);
}
free(ditherMatrix);
pnm_freepamrow(inrow);
*outTuplesP = outTuples;
}
static void
adaptRowToOutputFormat(struct pam * const inpamP,
tuple * const tuplerow,
struct pam * const outpamP) {
/*----------------------------------------------------------------------------
Convert the row in 'tuplerow', which is in a format described by
*inpamP, to the format described by *outpamP.
'tuplerow' must have enough allocated depth to do this.
-----------------------------------------------------------------------------*/
pnm_scaletuplerow(inpamP, tuplerow, tuplerow, outpamP->maxval);
if (strncmp(outpamP->tuple_type, "RGB", 3) == 0)
pnm_makerowrgb(inpamP, tuplerow);
}
