1 /* 2 * Copyright 2020 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 SkSamplingPriv_DEFINED 9 #define SkSamplingPriv_DEFINED 10 11 #include "include/core/SkSamplingOptions.h" 12 13 class SkReadBuffer; 14 class SkWriteBuffer; 15 16 // Private copy of SkFilterQuality, just for legacy deserialization 17 // Matches values in SkFilterQuality 18 enum SkLegacyFQ { 19 kNone_SkLegacyFQ = 0, //!< nearest-neighbor; fastest but lowest quality 20 kLow_SkLegacyFQ = 1, //!< bilerp 21 kMedium_SkLegacyFQ = 2, //!< bilerp + mipmaps; good for down-scaling 22 kHigh_SkLegacyFQ = 3, //!< bicubic resampling; slowest but good quality 23 24 kLast_SkLegacyFQ = kHigh_SkLegacyFQ, 25 }; 26 27 // Matches values in SkSamplingOptions::MediumBehavior 28 enum SkMediumAs { 29 kNearest_SkMediumAs, 30 kLinear_SkMediumAs, 31 }; 32 33 class SkSamplingPriv { 34 public: 35 enum { 36 kFlatSize = 3 * sizeof(uint32_t) // bool32 + [2 floats | 2 ints] 37 }; 38 39 // Returns true if the sampling can be ignored when the CTM is identity. NoChangeWithIdentityMatrix(const SkSamplingOptions & sampling)40 static bool NoChangeWithIdentityMatrix(const SkSamplingOptions& sampling) { 41 // If B == 0, the cubic resampler should have no effect for identity matrices 42 // https://entropymine.com/imageworsener/bicubic/ 43 return !sampling.useCubic || sampling.cubic.B == 0; 44 } 45 46 static SkSamplingOptions Read(SkReadBuffer&); 47 static void Write(SkWriteBuffer&, const SkSamplingOptions&); 48 49 static SkSamplingOptions FromFQ(SkLegacyFQ, SkMediumAs = kNearest_SkMediumAs); 50 }; 51 52 #endif 53