mike@reedtribe.org | e51755f | 2011-12-10 19:36:56 +0000 | [diff] [blame] | 1 | #include "SkArithmeticMode.h" |
| 2 | #include "SkColorPriv.h" |
| 3 | #include "SkUnPreMultiply.h" |
| 4 | |
| 5 | class SkArithmeticMode_scalar : public SkXfermode { |
| 6 | public: |
| 7 | SkArithmeticMode_scalar(SkScalar k1, SkScalar k2, SkScalar k3, SkScalar k4) { |
| 8 | fK[0] = k1; |
| 9 | fK[1] = k2; |
| 10 | fK[2] = k3; |
| 11 | fK[3] = k4; |
| 12 | } |
| 13 | |
| 14 | virtual void xfer32(SkPMColor dst[], const SkPMColor src[], int count, |
| 15 | const SkAlpha aa[]) SK_OVERRIDE; |
mike@reedtribe.org | e51755f | 2011-12-10 19:36:56 +0000 | [diff] [blame] | 16 | |
djsollen@google.com | ba28d03 | 2012-03-26 17:57:35 +0000 | [diff] [blame] | 17 | SK_DECLARE_UNFLATTENABLE_OBJECT() |
mike@reedtribe.org | e51755f | 2011-12-10 19:36:56 +0000 | [diff] [blame] | 18 | |
| 19 | private: |
| 20 | SkScalar fK[4]; |
| 21 | }; |
| 22 | |
mike@reedtribe.org | e51755f | 2011-12-10 19:36:56 +0000 | [diff] [blame] | 23 | static int pinToByte(int value) { |
| 24 | if (value < 0) { |
| 25 | value = 0; |
| 26 | } else if (value > 255) { |
| 27 | value = 255; |
| 28 | } |
| 29 | return value; |
| 30 | } |
| 31 | |
| 32 | static int arith(SkScalar k1, SkScalar k2, SkScalar k3, SkScalar k4, |
| 33 | int src, int dst) { |
| 34 | SkScalar result = SkScalarMul(k1, src * dst) + |
| 35 | SkScalarMul(k2, src) + |
| 36 | SkScalarMul(k3, dst) + |
| 37 | k4; |
| 38 | int res = SkScalarRoundToInt(result); |
| 39 | return pinToByte(res); |
| 40 | } |
| 41 | |
| 42 | static int blend(int src, int dst, int scale) { |
| 43 | return dst + ((src - dst) * scale >> 8); |
| 44 | } |
| 45 | |
| 46 | static bool needsUnpremul(int alpha) { |
| 47 | return 0 != alpha && 0xFF != alpha; |
| 48 | } |
| 49 | |
| 50 | void SkArithmeticMode_scalar::xfer32(SkPMColor dst[], const SkPMColor src[], |
| 51 | int count, const SkAlpha aaCoverage[]) { |
| 52 | SkScalar k1 = fK[0] / 255; |
| 53 | SkScalar k2 = fK[1]; |
| 54 | SkScalar k3 = fK[2]; |
| 55 | SkScalar k4 = fK[3] * 255; |
| 56 | |
| 57 | for (int i = 0; i < count; ++i) { |
| 58 | if ((NULL == aaCoverage) || aaCoverage[i]) { |
| 59 | SkPMColor sc = src[i]; |
| 60 | SkPMColor dc = dst[i]; |
| 61 | int sa = SkGetPackedA32(sc); |
| 62 | int da = SkGetPackedA32(dc); |
| 63 | |
| 64 | int srcNeedsUnpremul = needsUnpremul(sa); |
| 65 | int dstNeedsUnpremul = needsUnpremul(sa); |
| 66 | |
| 67 | int a, r, g, b; |
| 68 | |
tomhudson@google.com | 5efe0cb | 2012-04-10 19:14:48 +0000 | [diff] [blame] | 69 | if (!srcNeedsUnpremul && !dstNeedsUnpremul) { |
mike@reedtribe.org | e51755f | 2011-12-10 19:36:56 +0000 | [diff] [blame] | 70 | a = arith(k1, k2, k3, k4, sa, sa); |
| 71 | r = arith(k1, k2, k3, k4, SkGetPackedR32(sc), SkGetPackedR32(dc)); |
| 72 | g = arith(k1, k2, k3, k4, SkGetPackedG32(sc), SkGetPackedG32(dc)); |
| 73 | b = arith(k1, k2, k3, k4, SkGetPackedB32(sc), SkGetPackedB32(dc)); |
| 74 | } else { |
| 75 | int sr = SkGetPackedR32(sc); |
| 76 | int sg = SkGetPackedG32(sc); |
| 77 | int sb = SkGetPackedB32(sc); |
| 78 | if (srcNeedsUnpremul) { |
| 79 | SkUnPreMultiply::Scale scale = SkUnPreMultiply::GetScale(sa); |
| 80 | sr = SkUnPreMultiply::ApplyScale(scale, sr); |
| 81 | sg = SkUnPreMultiply::ApplyScale(scale, sg); |
| 82 | sb = SkUnPreMultiply::ApplyScale(scale, sb); |
| 83 | } |
| 84 | |
| 85 | int dr = SkGetPackedR32(dc); |
| 86 | int dg = SkGetPackedG32(dc); |
| 87 | int db = SkGetPackedB32(dc); |
| 88 | if (dstNeedsUnpremul) { |
| 89 | SkUnPreMultiply::Scale scale = SkUnPreMultiply::GetScale(da); |
| 90 | dr = SkUnPreMultiply::ApplyScale(scale, dr); |
| 91 | dg = SkUnPreMultiply::ApplyScale(scale, dg); |
| 92 | db = SkUnPreMultiply::ApplyScale(scale, db); |
| 93 | } |
| 94 | |
| 95 | a = arith(k1, k2, k3, k4, sa, sa); |
| 96 | r = arith(k1, k2, k3, k4, sr, dr); |
| 97 | g = arith(k1, k2, k3, k4, sg, dg); |
| 98 | b = arith(k1, k2, k3, k4, sb, db); |
| 99 | } |
| 100 | |
| 101 | // apply antialias coverage if necessary |
| 102 | if (aaCoverage && 0xFF != aaCoverage[i]) { |
| 103 | int scale = aaCoverage[i] + (aaCoverage[i] >> 7); |
| 104 | a = blend(a, SkGetPackedA32(sc), scale); |
| 105 | r = blend(r, SkGetPackedR32(sc), scale); |
| 106 | g = blend(g, SkGetPackedG32(sc), scale); |
| 107 | b = blend(b, SkGetPackedB32(sc), scale); |
| 108 | } |
| 109 | |
| 110 | // turn the result back into premul |
| 111 | if (0xFF != a) { |
| 112 | int scale = a + (a >> 7); |
| 113 | r = SkAlphaMul(r, scale); |
| 114 | g = SkAlphaMul(g, scale); |
| 115 | b = SkAlphaMul(b, scale); |
| 116 | } |
| 117 | dst[i] = SkPackARGB32(a, r, g, b); |
| 118 | } |
| 119 | } |
| 120 | } |
| 121 | |
| 122 | |
| 123 | /////////////////////////////////////////////////////////////////////////////// |
| 124 | |
| 125 | static bool fitsInBits(SkScalar x, int bits) { |
| 126 | #ifdef SK_SCALAR_IS_FIXED |
| 127 | x = SkAbs32(x); |
| 128 | x += 1 << 7; |
| 129 | x >>= 8; |
| 130 | return x < (1 << (bits - 1)); |
| 131 | #else |
| 132 | return SkScalarAbs(x) < (1 << (bits - 1)); |
| 133 | #endif |
| 134 | } |
| 135 | |
caryclark@google.com | 383d5d4 | 2012-06-06 12:09:18 +0000 | [diff] [blame^] | 136 | #if 0 // UNUSED |
mike@reedtribe.org | e51755f | 2011-12-10 19:36:56 +0000 | [diff] [blame] | 137 | static int32_t toDot8(SkScalar x) { |
| 138 | #ifdef SK_SCALAR_IS_FIXED |
| 139 | x += 1 << 7; |
| 140 | x >>= 8; |
| 141 | return x; |
| 142 | #else |
| 143 | return (int32_t)(x * 256); |
| 144 | #endif |
| 145 | } |
caryclark@google.com | 383d5d4 | 2012-06-06 12:09:18 +0000 | [diff] [blame^] | 146 | #endif |
mike@reedtribe.org | e51755f | 2011-12-10 19:36:56 +0000 | [diff] [blame] | 147 | |
| 148 | SkXfermode* SkArithmeticMode::Create(SkScalar k1, SkScalar k2, |
| 149 | SkScalar k3, SkScalar k4) { |
| 150 | if (fitsInBits(k1, 8) && fitsInBits(k2, 16) && |
| 151 | fitsInBits(k2, 16) && fitsInBits(k2, 24)) { |
| 152 | |
caryclark@google.com | 383d5d4 | 2012-06-06 12:09:18 +0000 | [diff] [blame^] | 153 | #if 0 // UNUSED |
mike@reedtribe.org | e51755f | 2011-12-10 19:36:56 +0000 | [diff] [blame] | 154 | int32_t i1 = toDot8(k1); |
| 155 | int32_t i2 = toDot8(k2); |
| 156 | int32_t i3 = toDot8(k3); |
| 157 | int32_t i4 = toDot8(k4); |
mike@reedtribe.org | e51755f | 2011-12-10 19:36:56 +0000 | [diff] [blame] | 158 | if (i1) { |
| 159 | return SkNEW_ARGS(SkArithmeticMode_quad, (i1, i2, i3, i4)); |
| 160 | } |
| 161 | if (0 == i2) { |
| 162 | return SkNEW_ARGS(SkArithmeticMode_dst, (i3, i4)); |
| 163 | } |
| 164 | if (0 == i3) { |
| 165 | return SkNEW_ARGS(SkArithmeticMode_src, (i2, i4)); |
| 166 | } |
| 167 | return SkNEW_ARGS(SkArithmeticMode_linear, (i2, i3, i4)); |
| 168 | #endif |
| 169 | } |
| 170 | return SkNEW_ARGS(SkArithmeticMode_scalar, (k1, k2, k3, k4)); |
| 171 | } |
| 172 | |