1 /* 2 * Copyright 2016 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #ifndef SkColorLookUpTable_DEFINED 9 #define SkColorLookUpTable_DEFINED 10 11 #include "SkRefCnt.h" 12 #include "SkTemplates.h" 13 14 static constexpr uint8_t kMaxColorChannels = 4; 15 16 class SkColorLookUpTable : public SkRefCnt { 17 public: 18 static constexpr uint8_t kOutputChannels = 3; 19 SkColorLookUpTable(uint8_t inputChannels,const uint8_t gridPoints[kMaxColorChannels])20 SkColorLookUpTable(uint8_t inputChannels, const uint8_t gridPoints[kMaxColorChannels]) 21 : fInputChannels(inputChannels) { 22 SkASSERT(inputChannels >= 1 && inputChannels <= kMaxColorChannels); 23 memcpy(fGridPoints, gridPoints, fInputChannels * sizeof(uint8_t)); 24 } 25 26 /** 27 * If fInputChannels == kOutputChannels == 3, performs tetrahedral interpolation, otherwise 28 * performs multilinear interpolation (ie LERP for n =1, bilinear for n=2, trilinear for n=3) 29 * with fInputChannels input dimensions and kOutputChannels output dimensions. 30 * |dst| can be |src| only when fInputChannels == kOutputChannels == 3 31 * |dst| is the destination pixel, must have at least kOutputChannels elements. 32 * |src| is the source pixel, must have at least fInputChannels elements. 33 */ 34 void interp(float* dst, const float* src) const; 35 inputChannels()36 int inputChannels() const { return fInputChannels; } 37 outputChannels()38 int outputChannels() const { return kOutputChannels; } 39 gridPoints(int dimension)40 int gridPoints(int dimension) const { 41 SkASSERT(dimension >= 0 && dimension < inputChannels()); 42 return fGridPoints[dimension]; 43 } 44 45 private: table()46 const float* table() const { 47 return SkTAddOffset<const float>(this, sizeof(SkColorLookUpTable)); 48 } 49 50 /** 51 * Performs tetrahedral interpolation with 3 input and 3 output dimensions. 52 * |dst| can be |src| 53 */ 54 void interp3D(float* dst, const float* src) const; 55 56 // recursively LERPs one dimension at a time. Used by interp() for the general case 57 float interpDimension(const float* src, int inputDimension, int outputDimension, 58 int index[kMaxColorChannels]) const; 59 60 uint8_t fInputChannels; 61 uint8_t fGridPoints[kMaxColorChannels]; 62 63 public: 64 // Objects of this type are created in a custom fashion using sk_malloc_throw 65 // and therefore must be sk_freed. 66 void* operator new(size_t size) = delete; new(size_t,void * p)67 void* operator new(size_t, void* p) { return p; } delete(void * p)68 void operator delete(void* p) { sk_free(p); } 69 }; 70 71 #endif 72