/*
* Handle the case of a large value or a value with a fraction part.
* See gxmatrix.h for more details.
*/
fixed
fixed_coeff_mult(fixed value, long coeff, const fixed_coeff *pfc, int maxb)
{
int shift = pfc->shift;
/*
* Test if the value is too large for simple long math.
*/
if ((value + (fixed_1 << (maxb - 1))) & (-fixed_1 << maxb)) {
/* The second argument of fixed_mult_quo must be non-negative. */
return
(coeff < 0 ?
-fixed_mult_quo(value, -coeff, fixed_1 << shift) :
fixed_mult_quo(value, coeff, fixed_1 << shift));
} else {
/*
* The construction above guarantees that the multiplications
* won't overflow the capacity of an int.
*/
return (fixed)
arith_rshift(fixed2int_var(value) * coeff
+ fixed2int(fixed_fraction(value) * coeff)
+ pfc->round, shift);
}
}
/*
* Define an implementation that uses trilinear interpolation.
*/
static void
interpolate_accum(const fixed * pi, const gx_color_lookup_table * pclt,
frac * pv, fixed factor)
{
const int *pdim = pclt->dims;
int m = pclt->m;
if (pclt->n > 3) {
/* Do two 3-D interpolations, interpolating between them. */
gx_color_lookup_table clt3;
int ix = fixed2int_var(pi[0]);
fixed fx = fixed_fraction(pi[0]);
clt3.n = 3;
clt3.dims[0] = pdim[1]; /* needed only for range checking */
clt3.dims[1] = pdim[2];
clt3.dims[2] = pdim[3];
clt3.m = m;
clt3.table = pclt->table + ix * pdim[1];
interpolate_accum(pi + 1, &clt3, pv, fixed_1);
if (ix == pdim[0] - 1)
return;
clt3.table += pdim[1];
interpolate_accum(pi + 1, &clt3, pv, fx);
} else {
int ic = fixed2int_var(pi[2]);
fixed fc = fixed_fraction(pi[2]);
uint dc1 = (ic == pdim[2] - 1 ? 0 : m);
int ib = fixed2int_var(pi[1]);
fixed fb = fixed_fraction(pi[1]);
uint db1 = (ib == pdim[1] - 1 ? 0 : pdim[2] * m);
uint dbc = (ib * pdim[2] + ic) * m;
uint dbc1 = db1 + dc1;
int ia = fixed2int_var(pi[0]);
fixed fa = fixed_fraction(pi[0]);
const byte *pa0 = pclt->table[ia].data + dbc;
const byte *pa1 =
(ia == pdim[0] - 1 ? pa0 : pclt->table[ia + 1].data + dbc);
int j;
/* The values to be interpolated are */
/* pa{0,1}[{0,db1,dc1,dbc1}]. */
for (j = 0; j < m; ++j, ++pa0, ++pa1) {
frac v000 = byte2frac(pa0[0]);
frac v001 = byte2frac(pa0[dc1]);
frac v010 = byte2frac(pa0[db1]);
frac v011 = byte2frac(pa0[dbc1]);
frac v100 = byte2frac(pa1[0]);
frac v101 = byte2frac(pa1[dc1]);
frac v110 = byte2frac(pa1[db1]);
frac v111 = byte2frac(pa1[dbc1]);
frac rv;
frac v00 = v000 +
(frac) arith_rshift((long)fc * (v001 - v000),
_fixed_shift);
frac v01 = v010 +
(frac) arith_rshift((long)fc * (v011 - v010),
_fixed_shift);
frac v10 = v100 +
(frac) arith_rshift((long)fc * (v101 - v100),
_fixed_shift);
frac v11 = v110 +
(frac) arith_rshift((long)fc * (v111 - v110),
_fixed_shift);
frac v0 = v00 +
(frac) arith_rshift((long)fb * (v01 - v00),
_fixed_shift);
frac v1 = v10 +
(frac) arith_rshift((long)fb * (v11 - v10),
_fixed_shift);
rv = v0 +
(frac) arith_rshift((long)fa * (v1 - v0),
_fixed_shift);
if (factor == fixed_1)
pv[j] = rv;
else
pv[j] += (frac) arith_rshift((long)factor * (rv - pv[j]),
_fixed_shift);
}
}
}
