1#include "SkUnitMappers.h" 2 3SkDiscreteMapper::SkDiscreteMapper(int segments) 4{ 5 if (segments < 2) 6 { 7 fSegments = 0; 8 fScale = 0; 9 } 10 else 11 { 12 if (segments > 0xFFFF) 13 segments = 0xFFFF; 14 fSegments = segments; 15 fScale = SK_Fract1 / (segments - 1); 16 } 17} 18 19uint16_t SkDiscreteMapper::mapUnit16(uint16_t input) 20{ 21 SkFixed x = input * fSegments >> 16; 22 x = x * fScale >> 14; 23 x += x << 15 >> 31; // map 0x10000 to 0xFFFF 24 return SkToU16(x); 25} 26 27SkDiscreteMapper::SkDiscreteMapper(SkFlattenableReadBuffer& rb) 28 : SkUnitMapper(rb) 29{ 30 fSegments = rb.readU32(); 31 fScale = rb.readU32(); 32} 33 34SkFlattenable::Factory SkDiscreteMapper::getFactory() 35{ 36 return Create; 37} 38 39SkFlattenable* SkDiscreteMapper::Create(SkFlattenableReadBuffer& rb) 40{ 41 return SkNEW_ARGS(SkDiscreteMapper, (rb)); 42} 43 44void SkDiscreteMapper::flatten(SkFlattenableWriteBuffer& wb) 45{ 46 this->INHERITED::flatten(wb); 47 48 wb.write32(fSegments); 49 wb.write32(fScale); 50} 51 52/////////////////////////////////////////////////////////////////////////////// 53 54uint16_t SkCosineMapper::mapUnit16(uint16_t input) 55{ 56 /* we want to call cosine(input * pi/2) treating input as [0...1) 57 however, the straight multitply would overflow 32bits since input is 58 16bits and pi/2 is 17bits, so we shift down our pi const before we mul 59 */ 60 SkFixed rads = (unsigned)(input * (SK_FixedPI >> 2)) >> 15; 61 SkFixed x = SkFixedCos(rads); 62 x += x << 15 >> 31; // map 0x10000 to 0xFFFF 63 return SkToU16(x); 64} 65 66SkCosineMapper::SkCosineMapper(SkFlattenableReadBuffer& rb) 67 : SkUnitMapper(rb) 68{ 69} 70 71SkFlattenable::Factory SkCosineMapper::getFactory() 72{ 73 return Create; 74} 75 76SkFlattenable* SkCosineMapper::Create(SkFlattenableReadBuffer& rb) 77{ 78 return SkNEW_ARGS(SkCosineMapper, (rb)); 79} 80 81