| Index: third_party/qcms/src/transform_util.c
|
| diff --git a/third_party/qcms/src/transform_util.c b/third_party/qcms/src/transform_util.c
|
| new file mode 100644
|
| index 0000000000000000000000000000000000000000..e60744742c393fdba7c68293066a47b1e2a0269d
|
| --- /dev/null
|
| +++ b/third_party/qcms/src/transform_util.c
|
| @@ -0,0 +1,639 @@
|
| +// qcms
|
| +// Copyright (C) 2009 Mozilla Foundation
|
| +//
|
| +// Permission is hereby granted, free of charge, to any person obtaining
|
| +// a copy of this software and associated documentation files (the "Software"),
|
| +// to deal in the Software without restriction, including without limitation
|
| +// the rights to use, copy, modify, merge, publish, distribute, sublicense,
|
| +// and/or sell copies of the Software, and to permit persons to whom the Software
|
| +// is furnished to do so, subject to the following conditions:
|
| +//
|
| +// The above copyright notice and this permission notice shall be included in
|
| +// all copies or substantial portions of the Software.
|
| +//
|
| +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
|
| +// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO
|
| +// THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
|
| +// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
|
| +// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
|
| +// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
|
| +// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
|
| +
|
| +#define _ISOC99_SOURCE /* for INFINITY */
|
| +
|
| +#include <math.h>
|
| +#include <assert.h>
|
| +#include <string.h> //memcpy
|
| +#include "qcmsint.h"
|
| +#include "transform_util.h"
|
| +#include "matrix.h"
|
| +
|
| +#if !defined(INFINITY)
|
| +#define INFINITY HUGE_VAL
|
| +#endif
|
| +
|
| +#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 function is 0..1
|
| +float lut_interp_linear(double input_value, uint16_t *table, size_t 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, size_t length)
|
| +{
|
| + /* Start scaling input_value to the length of the array: 65535*(length-1).
|
| + * We'll divide out the 65535 next */
|
| + uintptr_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, size_t 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 */
|
| + uintptr_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, size_t length)
|
| +{
|
| + int upper, lower;
|
| + value = value * (length - 1);
|
| + upper = ceil(value);
|
| + lower = floor(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, size_t 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 = -INFINITY;
|
| + } 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 = -INFINITY;
|
| + }
|
| + for (X = 0; X < 256; X++) {
|
| + float x = X / 255.0;
|
| + if (x >= interval) {
|
| + // XXX The equations are not exactly as definied in the spec but are
|
| + // algebraic equivilent.
|
| + // TODO Should division by 255 be for the whole expression.
|
| + gamma_table[X] = clamp_float(pow(a * x + b, y) + c + e);
|
| + } else {
|
| + gamma_table[X] = clamp_float(c * x + 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 clamp_float(float a)
|
| +{
|
| + /* One would naturally write this function as the following:
|
| + if (a > 1.)
|
| + return 1.;
|
| + else if (a < 0)
|
| + return 0;
|
| + else
|
| + return a;
|
| +
|
| + However, that version will let NaNs pass through which is undesirable
|
| + for most consumers.
|
| + */
|
| +
|
| + if (a > 1.)
|
| + return 1.;
|
| + else if (a >= 0)
|
| + return a;
|
| + else // a < 0 or a is NaN
|
| + return 0;
|
| +}
|
| +
|
| +unsigned char clamp_u8(float v)
|
| +{
|
| + if (v > 255.)
|
| + return 255;
|
| + else if (v < 0)
|
| + return 0;
|
| + else
|
| + return floor(v+.5);
|
| +}
|
| +
|
| +float u8Fixed8Number_to_float(uint16_t x)
|
| +{
|
| + // 0x0000 = 0.
|
| + // 0x0100 = 1.
|
| + // 0xffff = 255 + 255/256
|
| + return x/256.;
|
| +}
|
| +
|
| +/* The SSE2 code uses min & max which let NaNs pass through.
|
| + We want to try to prevent that here by ensuring that
|
| + gamma table is within expected values. */
|
| +void validate_gamma_table(float gamma_table[256])
|
| +{
|
| + int i;
|
| + for (i = 0; i < 256; i++) {
|
| + // Note: we check that the gamma is not in range
|
| + // instead of out of range so that we catch NaNs
|
| + if (!(gamma_table[i] >= 0.f && gamma_table[i] <= 1.f)) {
|
| + gamma_table[i] = 0.f;
|
| + }
|
| + }
|
| +}
|
| +
|
| +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);
|
| + }
|
| + }
|
| + }
|
| +
|
| + validate_gamma_table(gamma_table);
|
| +
|
| + 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 NumZeroes, int NumPoles)
|
| +{
|
| + int l = 1;
|
| + int r = 0x10000;
|
| + int x = 0, res; // 'int' Give spacing for negative values
|
| + 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 beginning of the table (Zeroes)
|
| + // and another arbitrary number of poles (FFFFh) at the end.
|
| +
|
| + // 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;
|
| +
|
| + // Does the curve belong to this case?
|
| + if (NumZeroes > 1 || NumPoles > 1)
|
| + {
|
| + int a, b, sample;
|
| +
|
| + // Identify if value fall downto 0 or FFFF zone
|
| + if (Value == 0) return 0;
|
| + // if (Value == 0xFFFF) return 0xFFFF;
|
| + sample = (length-1) * ((double) Value * (1./65535.));
|
| + if (LutTable[sample] == 0xffff)
|
| + return 0xffff;
|
| +
|
| + // else restrict to valid zone
|
| +
|
| + a = ((NumZeroes-1) * 0xFFFF) / (length-1);
|
| + b = ((length-1 - NumPoles) * 0xFFFF) / (length-1);
|
| +
|
| + l = a - 1;
|
| + r = b + 1;
|
| +
|
| + // Ensure a valid binary search range
|
| +
|
| + if (l < 1)
|
| + l = 1;
|
| + if (r > 0x10000)
|
| + r = 0x10000;
|
| +
|
| + // If the search range is inverted due to degeneracy,
|
| + // deem LutTable non-invertible in this search range.
|
| + // Refer to https://bugzil.la/1132467
|
| +
|
| + if (r <= l)
|
| + return 0;
|
| + }
|
| +
|
| + // For input 0, return that to maintain black level. Note the binary search
|
| + // does not. For example, it inverts the standard sRGB gamma curve to 7 at
|
| + // the origin, causing a black level error.
|
| +
|
| + if (Value == 0 && NumZeroes) {
|
| + 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);
|
| +
|
| + assert(cell0 >= 0);
|
| + assert(cell1 >= 0);
|
| + assert(cell0 < length);
|
| + assert(cell1 < length);
|
| +
|
| + 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);
|
| +}
|
| +
|
| +// December/16 2015 - Moved this code out of lut_inverse_interp16
|
| +// in order to save computation in invert_lut loop.
|
| +static void count_zeroes_and_poles(uint16_t *LutTable, int length, int *NumZeroes, int *NumPoles)
|
| +{
|
| + int z = 0, p = 0;
|
| +
|
| + while (LutTable[z] == 0 && z < length - 1)
|
| + z++;
|
| + *NumZeroes = z;
|
| +
|
| + while (LutTable[length - 1 - p] == 0xFFFF && p < length - 1)
|
| + p++;
|
| + *NumPoles = p;
|
| +}
|
| +
|
| +/*
|
| + 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, size_t out_length)
|
| +{
|
| + int NumZeroes;
|
| + int NumPoles;
|
| + 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;
|
| +
|
| + // December/16 2015 - Compute the input curve zero and pole extents outside
|
| + // the loop and pass them to lut_inverse_interp16.
|
| + count_zeroes_and_poles(table, length, &NumZeroes, &NumPoles);
|
| +
|
| + 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, NumZeroes, NumPoles);
|
| + }
|
| +
|
| + 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 gamma_table_uint[256];
|
| + uint16_t i;
|
| + uint16_t *inverted;
|
| + int inverted_size = 4096;
|
| +
|
| + 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, however 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
|
| + inverted = invert_lut(gamma_table_uint, 256, inverted_size);
|
| + if (!inverted)
|
| + return;
|
| + *output_gamma_lut = inverted;
|
| + *output_gamma_lut_length = inverted_size;
|
| + } 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);
|
| + }
|
| + }
|
| +
|
| +}
|
|
|