1 /* 2 * Copyright (C) 2006 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef SkTableMaskFilter_DEFINED 18 #define SkTableMaskFilter_DEFINED 19 20 #include "SkMaskFilter.h" 21 #include "SkScalar.h" 22 23 /** \class SkTableMaskFilter 24 25 Applies a table lookup on each of the alpha values in the mask. 26 Helper methods create some common tables (e.g. gamma, clipping) 27 */ 28 class SkTableMaskFilter : public SkMaskFilter { 29 public: 30 SkTableMaskFilter(); 31 SkTableMaskFilter(const uint8_t table[256]); 32 virtual ~SkTableMaskFilter(); 33 34 void setTable(const uint8_t table[256]); 35 36 /** Utility that sets the gamma table 37 */ 38 static void MakeGammaTable(uint8_t table[256], SkScalar gamma); 39 40 /** Utility that creates a clipping table: clamps values below min to 0 41 and above max to 255, and rescales the remaining into 0..255 42 */ 43 static void MakeClipTable(uint8_t table[256], uint8_t min, uint8_t max); 44 45 static SkTableMaskFilter* CreateGamma(SkScalar gamma) { 46 uint8_t table[256]; 47 MakeGammaTable(table, gamma); 48 return SkNEW_ARGS(SkTableMaskFilter, (table)); 49 } 50 51 static SkTableMaskFilter* CreateClip(uint8_t min, uint8_t max) { 52 uint8_t table[256]; 53 MakeClipTable(table, min, max); 54 return SkNEW_ARGS(SkTableMaskFilter, (table)); 55 } 56 57 // overrides from SkMaskFilter 58 virtual SkMask::Format getFormat(); 59 virtual bool filterMask(SkMask*, const SkMask&, const SkMatrix&, SkIPoint*); 60 61 // overrides from SkFlattenable 62 virtual void flatten(SkFlattenableWriteBuffer& wb); 63 virtual Factory getFactory(); 64 65 protected: 66 SkTableMaskFilter(SkFlattenableReadBuffer& rb); 67 static SkFlattenable* Factory(SkFlattenableReadBuffer&); 68 69 private: 70 uint8_t fTable[256]; 71 72 typedef SkMaskFilter INHERITED; 73 }; 74 75 #endif 76 77
