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/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkColorLookUpTable_DEFINED
#define SkColorLookUpTable_DEFINED
#include "SkRefCnt.h"
#include "SkTemplates.h"
static constexpr uint8_t kMaxColorChannels = 4;
class SkColorLookUpTable : public SkRefCnt {
public:
static constexpr uint8_t kOutputChannels = 3;
SkColorLookUpTable(uint8_t inputChannels, const uint8_t gridPoints[kMaxColorChannels])
: fInputChannels(inputChannels) {
SkASSERT(inputChannels >= 1 && inputChannels <= kMaxColorChannels);
memcpy(fGridPoints, gridPoints, fInputChannels * sizeof(uint8_t));
}
/**
* If fInputChannels == kOutputChannels == 3, performs tetrahedral interpolation, otherwise
* performs multilinear interpolation (ie LERP for n =1, bilinear for n=2, trilinear for n=3)
* with fInputChannels input dimensions and kOutputChannels output dimensions.
* |dst| can be |src| only when fInputChannels == kOutputChannels == 3
* |dst| is the destination pixel, must have at least kOutputChannels elements.
* |src| is the source pixel, must have at least fInputChannels elements.
*/
void interp(float* dst, const float* src) const;
int inputChannels() const { return fInputChannels; }
int outputChannels() const { return kOutputChannels; }
int gridPoints(int dimension) const {
SkASSERT(dimension >= 0 && dimension < inputChannels());
return fGridPoints[dimension];
}
private:
const float* table() const {
return SkTAddOffset<const float>(this, sizeof(SkColorLookUpTable));
}
/**
* Performs tetrahedral interpolation with 3 input and 3 output dimensions.
* |dst| can be |src|
*/
void interp3D(float* dst, const float* src) const;
// recursively LERPs one dimension at a time. Used by interp() for the general case
float interpDimension(const float* src, int inputDimension, int outputDimension,
int index[kMaxColorChannels]) const;
uint8_t fInputChannels;
uint8_t fGridPoints[kMaxColorChannels];
public:
// Objects of this type are created in a custom fashion using sk_malloc_throw
// and therefore must be sk_freed.
void* operator new(size_t size) = delete;
void* operator new(size_t, void* p) { return p; }
void operator delete(void* p) { sk_free(p); }
};
#endif
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