0008-Bug-687188-Skia-radial-gradients.patch (7619B)
1 From f941ea32e44a2436d235e83ef1a434289a9d9c1e Mon Sep 17 00:00:00 2001 2 From: George Wright <gwright@mozilla.com> 3 Date: Wed, 23 May 2012 11:40:25 -0400 4 Subject: [PATCH 08/10] Bug 755869 - [11] Re-apply bug 687188 - Skia 5 radial gradients should use the 0/1 color stop values 6 for clamping. r=mattwoodrow 7 8 --- 9 gfx/skia/src/effects/SkGradientShader.cpp | 76 +++++++++++++++++++++++------ 10 1 files changed, 61 insertions(+), 15 deletions(-) 11 12 diff --git a/gfx/skia/src/effects/SkGradientShader.cpp b/gfx/skia/src/effects/SkGradientShader.cpp 13 index 59ba48c..ea05a39 100644 14 --- a/gfx/skia/src/effects/SkGradientShader.cpp 15 +++ b/gfx/skia/src/effects/SkGradientShader.cpp 16 @@ -204,6 +204,7 @@ private: 17 mutable SkMallocPixelRef* fCache32PixelRef; 18 mutable unsigned fCacheAlpha; // the alpha value we used when we computed the cache. larger than 8bits so we can store uninitialized value 19 20 + static SkPMColor PremultiplyColor(SkColor c0, U8CPU alpha); 21 static void Build16bitCache(uint16_t[], SkColor c0, SkColor c1, int count); 22 static void Build32bitCache(SkPMColor[], SkColor c0, SkColor c1, int count, 23 U8CPU alpha); 24 @@ -507,6 +508,21 @@ static inline U8CPU dither_ceil_fixed_to_8(SkFixed n) { 25 return ((n << 1) - (n | (n >> 8))) >> 8; 26 } 27 28 +SkPMColor Gradient_Shader::PremultiplyColor(SkColor c0, U8CPU paintAlpha) 29 +{ 30 + SkFixed a = SkMulDiv255Round(SkColorGetA(c0), paintAlpha); 31 + SkFixed r = SkColorGetR(c0); 32 + SkFixed g = SkColorGetG(c0); 33 + SkFixed b = SkColorGetB(c0); 34 + 35 + a = SkIntToFixed(a) + 0x8000; 36 + r = SkIntToFixed(r) + 0x8000; 37 + g = SkIntToFixed(g) + 0x8000; 38 + b = SkIntToFixed(b) + 0x8000; 39 + 40 + return SkPremultiplyARGBInline(a >> 16, r >> 16, g >> 16, b >> 16); 41 +} 42 + 43 void Gradient_Shader::Build32bitCache(SkPMColor cache[], SkColor c0, SkColor c1, 44 int count, U8CPU paintAlpha) { 45 SkASSERT(count > 1); 46 @@ -628,14 +644,14 @@ static void complete_32bit_cache(SkPMColor* cache, int stride) { 47 const SkPMColor* Gradient_Shader::getCache32() const { 48 if (fCache32 == NULL) { 49 // double the count for dither entries 50 - const int entryCount = kCache32Count * 2; 51 + const int entryCount = kCache32Count * 2 + 2; 52 const size_t allocSize = sizeof(SkPMColor) * entryCount; 53 54 if (NULL == fCache32PixelRef) { 55 fCache32PixelRef = SkNEW_ARGS(SkMallocPixelRef, 56 (NULL, allocSize, NULL)); 57 } 58 - fCache32 = (SkPMColor*)fCache32PixelRef->getAddr(); 59 + fCache32 = (SkPMColor*)fCache32PixelRef->getAddr() + 1; 60 if (fColorCount == 2) { 61 Build32bitCache(fCache32, fOrigColors[0], fOrigColors[1], 62 kGradient32Length, fCacheAlpha); 63 @@ -659,7 +675,7 @@ const SkPMColor* Gradient_Shader::getCache32() const { 64 SkMallocPixelRef* newPR = SkNEW_ARGS(SkMallocPixelRef, 65 (NULL, allocSize, NULL)); 66 SkPMColor* linear = fCache32; // just computed linear data 67 - SkPMColor* mapped = (SkPMColor*)newPR->getAddr(); // storage for mapped data 68 + SkPMColor* mapped = (SkPMColor*)newPR->getAddr() + 1; // storage for mapped data 69 SkUnitMapper* map = fMapper; 70 for (int i = 0; i < kGradient32Length; i++) { 71 int index = map->mapUnit16((i << 8) | i) >> 8; 72 @@ -668,10 +684,13 @@ const SkPMColor* Gradient_Shader::getCache32() const { 73 } 74 fCache32PixelRef->unref(); 75 fCache32PixelRef = newPR; 76 - fCache32 = (SkPMColor*)newPR->getAddr(); 77 + fCache32 = (SkPMColor*)newPR->getAddr() + 1; 78 } 79 complete_32bit_cache(fCache32, kCache32Count); 80 } 81 + //Write the clamp colours into the first and last entries of fCache32 82 + fCache32[-1] = PremultiplyColor(fOrigColors[0], fCacheAlpha); 83 + fCache32[kCache32Count * 2] = PremultiplyColor(fOrigColors[fColorCount - 1], fCacheAlpha); 84 return fCache32; 85 } 86 87 @@ -857,6 +876,18 @@ void shadeSpan_linear_vertical(TileProc proc, SkFixed dx, SkFixed fx, 88 SkPMColor* SK_RESTRICT dstC, 89 const SkPMColor* SK_RESTRICT cache, 90 int toggle, int count) { 91 + if (proc == clamp_tileproc) { 92 + // Read out clamp values from beginning/end of the cache. No need to lerp 93 + // or dither 94 + if (fx < 0) { 95 + sk_memset32(dstC, cache[-1], count); 96 + return; 97 + } else if (fx > 0xFFFF) { 98 + sk_memset32(dstC, cache[Gradient_Shader::kCache32Count * 2], count); 99 + return; 100 + } 101 + } 102 + 103 // We're a vertical gradient, so no change in a span. 104 // If colors change sharply across the gradient, dithering is 105 // insufficient (it subsamples the color space) and we need to lerp. 106 @@ -875,6 +906,18 @@ void shadeSpan_linear_vertical_lerp(TileProc proc, SkFixed dx, SkFixed fx, 107 SkPMColor* SK_RESTRICT dstC, 108 const SkPMColor* SK_RESTRICT cache, 109 int toggle, int count) { 110 + if (proc == clamp_tileproc) { 111 + // Read out clamp values from beginning/end of the cache. No need to lerp 112 + // or dither 113 + if (fx < 0) { 114 + sk_memset32(dstC, cache[-1], count); 115 + return; 116 + } else if (fx > 0xFFFF) { 117 + sk_memset32(dstC, cache[Gradient_Shader::kCache32Count * 2], count); 118 + return; 119 + } 120 + } 121 + 122 // We're a vertical gradient, so no change in a span. 123 // If colors change sharply across the gradient, dithering is 124 // insufficient (it subsamples the color space) and we need to lerp. 125 @@ -900,10 +943,8 @@ void shadeSpan_linear_clamp(TileProc proc, SkFixed dx, SkFixed fx, 126 range.init(fx, dx, count, 0, Gradient_Shader::kGradient32Length); 127 128 if ((count = range.fCount0) > 0) { 129 - sk_memset32_dither(dstC, 130 - cache[toggle + range.fV0], 131 - cache[(toggle ^ Gradient_Shader::kDitherStride32) + range.fV0], 132 - count); 133 + // Shouldn't be any need to dither for clamping? 134 + sk_memset32(dstC, cache[-1], count); 135 dstC += count; 136 } 137 if ((count = range.fCount1) > 0) { 138 @@ -922,10 +963,8 @@ void shadeSpan_linear_clamp(TileProc proc, SkFixed dx, SkFixed fx, 139 } 140 } 141 if ((count = range.fCount2) > 0) { 142 - sk_memset32_dither(dstC, 143 - cache[toggle + range.fV1], 144 - cache[(toggle ^ Gradient_Shader::kDitherStride32) + range.fV1], 145 - count); 146 + // Shouldn't be any need to dither for clamping? 147 + sk_memset32(dstC, cache[Gradient_Shader::kCache32Count * 2], count); 148 } 149 } 150 151 @@ -1796,9 +1835,16 @@ void shadeSpan_twopoint_clamp(SkScalar fx, SkScalar dx, 152 for (; count > 0; --count) { 153 SkFixed t = two_point_radial(b, fx, fy, fSr2D2, foura, 154 fOneOverTwoA, posRoot); 155 - SkFixed index = SkClampMax(t, 0xFFFF); 156 - SkASSERT(index <= 0xFFFF); 157 - *dstC++ = cache[index >> Gradient_Shader::kCache32Shift]; 158 + 159 + if (t < 0) { 160 + *dstC++ = cache[-1]; 161 + } else if (t > 0xFFFF) { 162 + *dstC++ = cache[Gradient_Shader::kCache32Count * 2]; 163 + } else { 164 + SkASSERT(t <= 0xFFFF); 165 + *dstC++ = cache[t >> Gradient_Shader::kCache32Shift]; 166 + } 167 + 168 fx += dx; 169 fy += dy; 170 b += db; 171 -- 172 1.7.5.4