1 /* 2 * Copyright 2006 The Android Open Source Project 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 AvoidXfermode_DEFINED 9 #define AvoidXfermode_DEFINED 10 11 #include "SkColor.h" 12 #include "SkTypes.h" 13 #include "SkXfermode.h" 14 15 /** \class AvoidXfermode 16 17 This xfermode will draw the src everywhere except on top of the specified 18 color. 19 */ 20 class AvoidXfermode : public SkXfermode { 21 public: 22 enum Mode { 23 kAvoidColor_Mode, //!< draw everywhere except on the opColor 24 kTargetColor_Mode //!< draw only on top of the opColor 25 }; 26 27 /** This xfermode draws, or doesn't draw, based on the destination's 28 distance from an op-color. 29 30 There are two modes, and each mode interprets a tolerance value. 31 32 Avoid: In this mode, drawing is allowed only on destination pixels that 33 are different from the op-color. 34 Tolerance near 0: avoid any colors even remotely similar to the op-color 35 Tolerance near 255: avoid only colors nearly identical to the op-color 36 37 Target: In this mode, drawing only occurs on destination pixels that 38 are similar to the op-color 39 Tolerance near 0: draw only on colors that are nearly identical to the op-color 40 Tolerance near 255: draw on any colors even remotely similar to the op-color 41 */ Create(SkColor opColor,U8CPU tolerance,Mode mode)42 static AvoidXfermode* Create(SkColor opColor, U8CPU tolerance, Mode mode) { 43 return SkNEW_ARGS(AvoidXfermode, (opColor, tolerance, mode)); 44 } 45 46 // overrides from SkXfermode 47 void xfer32(SkPMColor dst[], const SkPMColor src[], int count, 48 const SkAlpha aa[]) const override; 49 void xfer16(uint16_t dst[], const SkPMColor src[], int count, 50 const SkAlpha aa[]) const override; 51 void xferA8(SkAlpha dst[], const SkPMColor src[], int count, 52 const SkAlpha aa[]) const override; 53 54 SK_TO_STRING_OVERRIDE() 55 SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(AvoidXfermode) 56 57 protected: 58 AvoidXfermode(SkColor opColor, U8CPU tolerance, Mode mode); 59 void flatten(SkWriteBuffer&) const override; 60 61 private: 62 SkColor fOpColor; 63 uint32_t fDistMul; // x.14 cached from fTolerance 64 uint8_t fTolerance; 65 Mode fMode; 66 67 typedef SkXfermode INHERITED; 68 }; 69 70 #endif 71