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spiderweb/gfx/qcms/transform_util.c

517 строки
18 KiB
C
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#include <math.h>
#include <assert.h>
#include <string.h> //memcpy
#include "qcmsint.h"
#include "transform_util.h"
#include "matrix.h"
#define PARAMETRIC_CURVE_TYPE 0x70617261 //'para'
/* value must be a value between 0 and 1 */
//XXX: is the above a good restriction to have?
// the output range of this functions is 0..1
float lut_interp_linear(double input_value, uint16_t *table, int length)
{
int upper, lower;
float value;
input_value = input_value * (length - 1); // scale to length of the array
upper = ceil(input_value);
lower = floor(input_value);
//XXX: can we be more performant here?
value = table[upper]*(1. - (upper - input_value)) + table[lower]*(upper - input_value);
/* scale the value */
return value * (1.f/65535.f);
}
/* same as above but takes and returns a uint16_t value representing a range from 0..1 */
uint16_t lut_interp_linear16(uint16_t input_value, uint16_t *table, int length)
{
/* Start scaling input_value to the length of the array: 65535*(length-1).
* We'll divide out the 65535 next */
uint32_t value = (input_value * (length - 1));
uint32_t upper = (value + 65534) / 65535; /* equivalent to ceil(value/65535) */
uint32_t lower = value / 65535; /* equivalent to floor(value/65535) */
/* interp is the distance from upper to value scaled to 0..65535 */
uint32_t interp = value % 65535;
value = (table[upper]*(interp) + table[lower]*(65535 - interp))/65535; // 0..65535*65535
return value;
}
/* same as above but takes an input_value from 0..PRECACHE_OUTPUT_MAX
* and returns a uint8_t value representing a range from 0..1 */
static
uint8_t lut_interp_linear_precache_output(uint32_t input_value, uint16_t *table, int length)
{
/* Start scaling input_value to the length of the array: PRECACHE_OUTPUT_MAX*(length-1).
* We'll divide out the PRECACHE_OUTPUT_MAX next */
uint32_t value = (input_value * (length - 1));
/* equivalent to ceil(value/PRECACHE_OUTPUT_MAX) */
uint32_t upper = (value + PRECACHE_OUTPUT_MAX-1) / PRECACHE_OUTPUT_MAX;
/* equivalent to floor(value/PRECACHE_OUTPUT_MAX) */
uint32_t lower = value / PRECACHE_OUTPUT_MAX;
/* interp is the distance from upper to value scaled to 0..PRECACHE_OUTPUT_MAX */
uint32_t interp = value % PRECACHE_OUTPUT_MAX;
/* the table values range from 0..65535 */
value = (table[upper]*(interp) + table[lower]*(PRECACHE_OUTPUT_MAX - interp)); // 0..(65535*PRECACHE_OUTPUT_MAX)
/* round and scale */
value += (PRECACHE_OUTPUT_MAX*65535/255)/2;
value /= (PRECACHE_OUTPUT_MAX*65535/255); // scale to 0..255
return value;
}
/* value must be a value between 0 and 1 */
//XXX: is the above a good restriction to have?
float lut_interp_linear_float(float value, float *table, int length)
{
int upper, lower;
value = value * (length - 1);
upper = ceilf(value);
lower = floorf(value);
//XXX: can we be more performant here?
value = table[upper]*(1. - (upper - value)) + table[lower]*(upper - value);
/* scale the value */
return value;
}
#if 0
/* if we use a different representation i.e. one that goes from 0 to 0x1000 we can be more efficient
* because we can avoid the divisions and use a shifting instead */
/* same as above but takes and returns a uint16_t value representing a range from 0..1 */
uint16_t lut_interp_linear16(uint16_t input_value, uint16_t *table, int length)
{
uint32_t value = (input_value * (length - 1));
uint32_t upper = (value + 4095) / 4096; /* equivalent to ceil(value/4096) */
uint32_t lower = value / 4096; /* equivalent to floor(value/4096) */
uint32_t interp = value % 4096;
value = (table[upper]*(interp) + table[lower]*(4096 - interp))/4096; // 0..4096*4096
return value;
}
#endif
void compute_curve_gamma_table_type1(float gamma_table[256], uint16_t gamma)
{
unsigned int i;
float gamma_float = u8Fixed8Number_to_float(gamma);
for (i = 0; i < 256; i++) {
// 0..1^(0..255 + 255/256) will always be between 0 and 1
gamma_table[i] = pow(i/255., gamma_float);
}
}
void compute_curve_gamma_table_type2(float gamma_table[256], uint16_t *table, int length)
{
unsigned int i;
for (i = 0; i < 256; i++) {
gamma_table[i] = lut_interp_linear(i/255., table, length);
}
}
void compute_curve_gamma_table_type_parametric(float gamma_table[256], float parameter[7], int count)
{
size_t X;
float interval;
float a, b, c, e, f;
float y = parameter[0];
if (count == 0) {
a = 1;
b = 0;
c = 0;
e = 0;
f = 0;
interval = -1;
} else if(count == 1) {
a = parameter[1];
b = parameter[2];
c = 0;
e = 0;
f = 0;
interval = -1 * parameter[2] / parameter[1];
} else if(count == 2) {
a = parameter[1];
b = parameter[2];
c = 0;
e = parameter[3];
f = parameter[3];
interval = -1 * parameter[2] / parameter[1];
} else if(count == 3) {
a = parameter[1];
b = parameter[2];
c = parameter[3];
e = -c;
f = 0;
interval = parameter[4];
} else if(count == 4) {
a = parameter[1];
b = parameter[2];
c = parameter[3];
e = parameter[5] - c;
f = parameter[6];
interval = parameter[4];
} else {
assert(0 && "invalid parametric function type.");
a = 1;
b = 0;
c = 0;
e = 0;
f = 0;
interval = -1;
}
for (X = 0; X < 256; X++) {
if (X >= interval) {
// XXX The equations are not exactly as defined in the spec but are
// algebraically equivalent.
// TODO Should division by 255 be for the whole expression.
gamma_table[X] = clamp_float(pow(a * X / 255. + b, y) + c + e);
} else {
gamma_table[X] = clamp_float(c * X / 255. + f);
}
}
}
void compute_curve_gamma_table_type0(float gamma_table[256])
{
unsigned int i;
for (i = 0; i < 256; i++) {
gamma_table[i] = i/255.;
}
}
float *build_input_gamma_table(struct curveType *TRC)
{
float *gamma_table;
if (!TRC) return NULL;
gamma_table = malloc(sizeof(float)*256);
if (gamma_table) {
if (TRC->type == PARAMETRIC_CURVE_TYPE) {
compute_curve_gamma_table_type_parametric(gamma_table, TRC->parameter, TRC->count);
} else {
if (TRC->count == 0) {
compute_curve_gamma_table_type0(gamma_table);
} else if (TRC->count == 1) {
compute_curve_gamma_table_type1(gamma_table, TRC->data[0]);
} else {
compute_curve_gamma_table_type2(gamma_table, TRC->data, TRC->count);
}
}
}
return gamma_table;
}
struct matrix build_colorant_matrix(qcms_profile *p)
{
struct matrix result;
result.m[0][0] = s15Fixed16Number_to_float(p->redColorant.X);
result.m[0][1] = s15Fixed16Number_to_float(p->greenColorant.X);
result.m[0][2] = s15Fixed16Number_to_float(p->blueColorant.X);
result.m[1][0] = s15Fixed16Number_to_float(p->redColorant.Y);
result.m[1][1] = s15Fixed16Number_to_float(p->greenColorant.Y);
result.m[1][2] = s15Fixed16Number_to_float(p->blueColorant.Y);
result.m[2][0] = s15Fixed16Number_to_float(p->redColorant.Z);
result.m[2][1] = s15Fixed16Number_to_float(p->greenColorant.Z);
result.m[2][2] = s15Fixed16Number_to_float(p->blueColorant.Z);
result.invalid = false;
return result;
}
/* The following code is copied nearly directly from lcms.
* I think it could be much better. For example, Argyll seems to have better code in
* icmTable_lookup_bwd and icmTable_setup_bwd. However, for now this is a quick way
* to a working solution and allows for easy comparing with lcms. */
uint16_fract_t lut_inverse_interp16(uint16_t Value, uint16_t LutTable[], int length)
{
int l = 1;
int r = 0x10000;
int x = 0, res; // 'int' Give spacing for negative values
int NumZeroes, NumPoles;
int cell0, cell1;
double val2;
double y0, y1, x0, x1;
double a, b, f;
// July/27 2001 - Expanded to handle degenerated curves with an arbitrary
// number of elements containing 0 at the begining of the table (Zeroes)
// and another arbitrary number of poles (FFFFh) at the end.
// First the zero and pole extents are computed, then value is compared.
NumZeroes = 0;
while (LutTable[NumZeroes] == 0 && NumZeroes < length-1)
NumZeroes++;
// There are no zeros at the beginning and we are trying to find a zero, so
// return anything. It seems zero would be the less destructive choice
/* I'm not sure that this makes sense, but oh well... */
if (NumZeroes == 0 && Value == 0)
return 0;
NumPoles = 0;
while (LutTable[length-1- NumPoles] == 0xFFFF && NumPoles < length-1)
NumPoles++;
// Does the curve belong to this case?
if (NumZeroes > 1 || NumPoles > 1)
{
int a, b;
// Identify if value fall downto 0 or FFFF zone
if (Value == 0) return 0;
// if (Value == 0xFFFF) return 0xFFFF;
// else restrict to valid zone
if (NumZeroes > 1) {
a = ((NumZeroes-1) * 0xFFFF) / (length-1);
l = a - 1;
}
if (NumPoles > 1) {
b = ((length-1 - NumPoles) * 0xFFFF) / (length-1);
r = b + 1;
}
}
if (r <= l) {
// If this happens LutTable is not invertible
return 0;
}
// Seems not a degenerated case... apply binary search
while (r > l) {
x = (l + r) / 2;
res = (int) lut_interp_linear16((uint16_fract_t) (x-1), LutTable, length);
if (res == Value) {
// Found exact match.
return (uint16_fract_t) (x - 1);
}
if (res > Value) r = x - 1;
else l = x + 1;
}
// Not found, should we interpolate?
// Get surrounding nodes
assert(x >= 1);
val2 = (length-1) * ((double) (x - 1) / 65535.0);
cell0 = (int) floor(val2);
cell1 = (int) ceil(val2);
if (cell0 == cell1) return (uint16_fract_t) x;
y0 = LutTable[cell0] ;
x0 = (65535.0 * cell0) / (length-1);
y1 = LutTable[cell1] ;
x1 = (65535.0 * cell1) / (length-1);
a = (y1 - y0) / (x1 - x0);
b = y0 - a * x0;
if (fabs(a) < 0.01) return (uint16_fract_t) x;
f = ((Value - b) / a);
if (f < 0.0) return (uint16_fract_t) 0;
if (f >= 65535.0) return (uint16_fract_t) 0xFFFF;
return (uint16_fract_t) floor(f + 0.5);
}
/*
The number of entries needed to invert a lookup table should not
necessarily be the same as the original number of entries. This is
especially true of lookup tables that have a small number of entries.
For example:
Using a table like:
{0, 3104, 14263, 34802, 65535}
invert_lut will produce an inverse of:
{3, 34459, 47529, 56801, 65535}
which has an maximum error of about 9855 (pixel difference of ~38.346)
For now, we punt the decision of output size to the caller. */
static uint16_t *invert_lut(uint16_t *table, int length, int out_length)
{
int i;
/* for now we invert the lut by creating a lut of size out_length
* and attempting to lookup a value for each entry using lut_inverse_interp16 */
uint16_t *output = malloc(sizeof(uint16_t)*out_length);
if (!output)
return NULL;
for (i = 0; i < out_length; i++) {
double x = ((double) i * 65535.) / (double) (out_length - 1);
uint16_fract_t input = floor(x + .5);
output[i] = lut_inverse_interp16(input, table, length);
}
return output;
}
static void compute_precache_pow(uint8_t *output, float gamma)
{
uint32_t v = 0;
for (v = 0; v < PRECACHE_OUTPUT_SIZE; v++) {
//XXX: don't do integer/float conversion... and round?
output[v] = 255. * pow(v/(double)PRECACHE_OUTPUT_MAX, gamma);
}
}
void compute_precache_lut(uint8_t *output, uint16_t *table, int length)
{
uint32_t v = 0;
for (v = 0; v < PRECACHE_OUTPUT_SIZE; v++) {
output[v] = lut_interp_linear_precache_output(v, table, length);
}
}
void compute_precache_linear(uint8_t *output)
{
uint32_t v = 0;
for (v = 0; v < PRECACHE_OUTPUT_SIZE; v++) {
//XXX: round?
output[v] = v / (PRECACHE_OUTPUT_SIZE/256);
}
}
qcms_bool compute_precache(struct curveType *trc, uint8_t *output)
{
if (trc->type == PARAMETRIC_CURVE_TYPE) {
float gamma_table[256];
uint16_t gamma_table_uint[256];
uint16_t i;
uint16_t *inverted;
int inverted_size = 256;
compute_curve_gamma_table_type_parametric(gamma_table, trc->parameter, trc->count);
for(i = 0; i < 256; i++) {
gamma_table_uint[i] = (uint16_t)(gamma_table[i] * 65535);
}
//XXX: the choice of a minimum of 256 here is not backed by any theory,
// measurement or data, howeve r it is what lcms uses.
// the maximum number we would need is 65535 because that's the
// accuracy used for computing the pre cache table
if (inverted_size < 256)
inverted_size = 256;
inverted = invert_lut(gamma_table_uint, 256, inverted_size);
if (!inverted)
return false;
compute_precache_lut(output, inverted, inverted_size);
free(inverted);
} else {
if (trc->count == 0) {
compute_precache_linear(output);
} else if (trc->count == 1) {
compute_precache_pow(output, 1./u8Fixed8Number_to_float(trc->data[0]));
} else {
uint16_t *inverted;
int inverted_size = trc->count;
//XXX: the choice of a minimum of 256 here is not backed by any theory,
// measurement or data, howeve r it is what lcms uses.
// the maximum number we would need is 65535 because that's the
// accuracy used for computing the pre cache table
if (inverted_size < 256)
inverted_size = 256;
inverted = invert_lut(trc->data, trc->count, inverted_size);
if (!inverted)
return false;
compute_precache_lut(output, inverted, inverted_size);
free(inverted);
}
}
return true;
}
static uint16_t *build_linear_table(int length)
{
int i;
uint16_t *output = malloc(sizeof(uint16_t)*length);
if (!output)
return NULL;
for (i = 0; i < length; i++) {
double x = ((double) i * 65535.) / (double) (length - 1);
uint16_fract_t input = floor(x + .5);
output[i] = input;
}
return output;
}
static uint16_t *build_pow_table(float gamma, int length)
{
int i;
uint16_t *output = malloc(sizeof(uint16_t)*length);
if (!output)
return NULL;
for (i = 0; i < length; i++) {
uint16_fract_t result;
double x = ((double) i) / (double) (length - 1);
x = pow(x, gamma); //XXX turn this conversion into a function
result = floor(x*65535. + .5);
output[i] = result;
}
return output;
}
void build_output_lut(struct curveType *trc,
uint16_t **output_gamma_lut, size_t *output_gamma_lut_length)
{
if (trc->type == PARAMETRIC_CURVE_TYPE) {
float gamma_table[256];
uint16_t i;
uint16_t *output = malloc(sizeof(uint16_t)*256);
if (!output) {
*output_gamma_lut = NULL;
return;
}
compute_curve_gamma_table_type_parametric(gamma_table, trc->parameter, trc->count);
*output_gamma_lut_length = 256;
for(i = 0; i < 256; i++) {
output[i] = (uint16_t)(gamma_table[i] * 65535);
}
*output_gamma_lut = output;
} else {
if (trc->count == 0) {
*output_gamma_lut = build_linear_table(4096);
*output_gamma_lut_length = 4096;
} else if (trc->count == 1) {
float gamma = 1./u8Fixed8Number_to_float(trc->data[0]);
*output_gamma_lut = build_pow_table(gamma, 4096);
*output_gamma_lut_length = 4096;
} else {
//XXX: the choice of a minimum of 256 here is not backed by any theory,
// measurement or data, however it is what lcms uses.
*output_gamma_lut_length = trc->count;
if (*output_gamma_lut_length < 256)
*output_gamma_lut_length = 256;
*output_gamma_lut = invert_lut(trc->data, trc->count, *output_gamma_lut_length);
}
}
}
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