1 /* 2 * Copyright 2017 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 GrNonlinearColorSpaceXformEffect_DEFINED 9 #define GrNonlinearColorSpaceXformEffect_DEFINED 10 11 #include "GrFragmentProcessor.h" 12 #include "SkColorSpace.h" 13 #include "SkMatrix44.h" 14 15 /** 16 * The output of this effect is the input, transformed into a different color space. 17 * This effect is used for nonlinear blending color space support - it does not assume HW sRGB 18 * capabilities, and performs both the source and destination transfer functions numerically in 19 * the shader. Any parametric transfer function is supported. Because of the nonlinear blending, 20 * premultiplication is also nonlinear - source pixels are unpremultiplied before the source 21 * transfer function, and then premultiplied after the destination transfer function. 22 */ 23 class GrNonlinearColorSpaceXformEffect : public GrFragmentProcessor { 24 public: 25 /** 26 * The conversion effect is only well defined with a valid source and destination color space. 27 * This will return nullptr if either space is nullptr, if both spaces are equal, or if either 28 * space has a non-parametric transfer funcion (e.g. lookup table or A2B). 29 */ 30 static sk_sp<GrFragmentProcessor> Make(const SkColorSpace* src, const SkColorSpace* dst); 31 32 const char* name() const override { return "NonlinearColorSpaceXform"; } 33 34 static const int kNumTransferFnCoeffs = 7; 35 36 /** 37 * Flags that specify which operations are performed for one particular conversion. 38 * Some color space pairs may not need all operations, if one or both transfer functions 39 * is linear, or if the gamuts are the same. 40 */ 41 enum Ops { 42 kSrcTransfer_Op = 0x1, 43 kGamutXform_Op = 0x2, 44 kDstTransfer_Op = 0x4, 45 }; 46 47 uint32_t ops() const { return fOps; } 48 const float* srcTransferFnCoeffs() const { return fSrcTransferFnCoeffs; } 49 const float* dstTransferFnCoeffs() const { return fDstTransferFnCoeffs; } 50 const SkMatrix44& gamutXform() const { return fGamutXform; } 51 52 private: 53 GrNonlinearColorSpaceXformEffect(uint32_t ops, 54 const SkColorSpaceTransferFn& srcTransferFn, 55 const SkColorSpaceTransferFn& dstTransferFn, 56 const SkMatrix44& gamutXform); 57 58 GrGLSLFragmentProcessor* onCreateGLSLInstance() const override; 59 void onGetGLSLProcessorKey(const GrShaderCaps&, GrProcessorKeyBuilder*) const override; 60 bool onIsEqual(const GrFragmentProcessor&) const override; 61 62 float fSrcTransferFnCoeffs[kNumTransferFnCoeffs]; 63 float fDstTransferFnCoeffs[kNumTransferFnCoeffs]; 64 SkMatrix44 fGamutXform; 65 uint32_t fOps; 66 67 GR_DECLARE_FRAGMENT_PROCESSOR_TEST 68 69 typedef GrFragmentProcessor INHERITED; 70 }; 71 72 #endif 73
