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From f941ea32e44a2436d235e83ef1a434289a9d9c1e Mon Sep 17 00:00:00 2001
From: George Wright <gwright@mozilla.com>
Date: Wed, 23 May 2012 11:40:25 -0400
radial gradients should use the 0/1 color stop values
for clamping. r=mattwoodrow
---
gfx/skia/src/effects/SkGradientShader.cpp | 76 +++++++++++++++++++++++------
1 files changed, 61 insertions(+), 15 deletions(-)
diff --git a/gfx/skia/src/effects/SkGradientShader.cpp b/gfx/skia/src/effects/SkGradientShader.cpp
index 59ba48c..ea05a39 100644
--- a/gfx/skia/src/effects/SkGradientShader.cpp
+++ b/gfx/skia/src/effects/SkGradientShader.cpp
@@ -204,6 +204,7 @@ private:
mutable SkMallocPixelRef* fCache32PixelRef;
mutable unsigned fCacheAlpha; // the alpha value we used when we computed the cache. larger than 8bits so we can store uninitialized value
+ static SkPMColor PremultiplyColor(SkColor c0, U8CPU alpha);
static void Build16bitCache(uint16_t[], SkColor c0, SkColor c1, int count);
static void Build32bitCache(SkPMColor[], SkColor c0, SkColor c1, int count,
U8CPU alpha);
@@ -507,6 +508,21 @@ static inline U8CPU dither_ceil_fixed_to_8(SkFixed n) {
return ((n << 1) - (n | (n >> 8))) >> 8;
}
+SkPMColor Gradient_Shader::PremultiplyColor(SkColor c0, U8CPU paintAlpha)
+{
+ SkFixed a = SkMulDiv255Round(SkColorGetA(c0), paintAlpha);
+ SkFixed r = SkColorGetR(c0);
+ SkFixed g = SkColorGetG(c0);
+ SkFixed b = SkColorGetB(c0);
+
+ a = SkIntToFixed(a) + 0x8000;
+ r = SkIntToFixed(r) + 0x8000;
+ g = SkIntToFixed(g) + 0x8000;
+ b = SkIntToFixed(b) + 0x8000;
+
+ return SkPremultiplyARGBInline(a >> 16, r >> 16, g >> 16, b >> 16);
+}
+
void Gradient_Shader::Build32bitCache(SkPMColor cache[], SkColor c0, SkColor c1,
int count, U8CPU paintAlpha) {
SkASSERT(count > 1);
@@ -628,14 +644,14 @@ static void complete_32bit_cache(SkPMColor* cache, int stride) {
const SkPMColor* Gradient_Shader::getCache32() const {
if (fCache32 == NULL) {
// double the count for dither entries
- const int entryCount = kCache32Count * 2;
+ const int entryCount = kCache32Count * 2 + 2;
const size_t allocSize = sizeof(SkPMColor) * entryCount;
if (NULL == fCache32PixelRef) {
fCache32PixelRef = SkNEW_ARGS(SkMallocPixelRef,
(NULL, allocSize, NULL));
}
- fCache32 = (SkPMColor*)fCache32PixelRef->getAddr();
+ fCache32 = (SkPMColor*)fCache32PixelRef->getAddr() + 1;
if (fColorCount == 2) {
Build32bitCache(fCache32, fOrigColors[0], fOrigColors[1],
kGradient32Length, fCacheAlpha);
@@ -659,7 +675,7 @@ const SkPMColor* Gradient_Shader::getCache32() const {
SkMallocPixelRef* newPR = SkNEW_ARGS(SkMallocPixelRef,
(NULL, allocSize, NULL));
SkPMColor* linear = fCache32; // just computed linear data
- SkPMColor* mapped = (SkPMColor*)newPR->getAddr(); // storage for mapped data
+ SkPMColor* mapped = (SkPMColor*)newPR->getAddr() + 1; // storage for mapped data
SkUnitMapper* map = fMapper;
for (int i = 0; i < kGradient32Length; i++) {
int index = map->mapUnit16((i << 8) | i) >> 8;
@@ -668,10 +684,13 @@ const SkPMColor* Gradient_Shader::getCache32() const {
}
fCache32PixelRef->unref();
fCache32PixelRef = newPR;
- fCache32 = (SkPMColor*)newPR->getAddr();
+ fCache32 = (SkPMColor*)newPR->getAddr() + 1;
}
complete_32bit_cache(fCache32, kCache32Count);
}
+ //Write the clamp colours into the first and last entries of fCache32
+ fCache32[-1] = PremultiplyColor(fOrigColors[0], fCacheAlpha);
+ fCache32[kCache32Count * 2] = PremultiplyColor(fOrigColors[fColorCount - 1], fCacheAlpha);
return fCache32;
}
@@ -857,6 +876,18 @@ void shadeSpan_linear_vertical(TileProc proc, SkFixed dx, SkFixed fx,
SkPMColor* SK_RESTRICT dstC,
const SkPMColor* SK_RESTRICT cache,
int toggle, int count) {
+ if (proc == clamp_tileproc) {
+ // Read out clamp values from beginning/end of the cache. No need to lerp
+ // or dither
+ if (fx < 0) {
+ sk_memset32(dstC, cache[-1], count);
+ return;
+ } else if (fx > 0xFFFF) {
+ sk_memset32(dstC, cache[Gradient_Shader::kCache32Count * 2], count);
+ return;
+ }
+ }
+
// We're a vertical gradient, so no change in a span.
// If colors change sharply across the gradient, dithering is
// insufficient (it subsamples the color space) and we need to lerp.
@@ -875,6 +906,18 @@ void shadeSpan_linear_vertical_lerp(TileProc proc, SkFixed dx, SkFixed fx,
SkPMColor* SK_RESTRICT dstC,
const SkPMColor* SK_RESTRICT cache,
int toggle, int count) {
+ if (proc == clamp_tileproc) {
+ // Read out clamp values from beginning/end of the cache. No need to lerp
+ // or dither
+ if (fx < 0) {
+ sk_memset32(dstC, cache[-1], count);
+ return;
+ } else if (fx > 0xFFFF) {
+ sk_memset32(dstC, cache[Gradient_Shader::kCache32Count * 2], count);
+ return;
+ }
+ }
+
// We're a vertical gradient, so no change in a span.
// If colors change sharply across the gradient, dithering is
// insufficient (it subsamples the color space) and we need to lerp.
@@ -900,10 +943,8 @@ void shadeSpan_linear_clamp(TileProc proc, SkFixed dx, SkFixed fx,
range.init(fx, dx, count, 0, Gradient_Shader::kGradient32Length);
if ((count = range.fCount0) > 0) {
- sk_memset32_dither(dstC,
- cache[toggle + range.fV0],
- cache[(toggle ^ Gradient_Shader::kDitherStride32) + range.fV0],
- count);
+ // Shouldn't be any need to dither for clamping?
+ sk_memset32(dstC, cache[-1], count);
dstC += count;
}
if ((count = range.fCount1) > 0) {
@@ -922,10 +963,8 @@ void shadeSpan_linear_clamp(TileProc proc, SkFixed dx, SkFixed fx,
}
}
if ((count = range.fCount2) > 0) {
- sk_memset32_dither(dstC,
- cache[toggle + range.fV1],
- cache[(toggle ^ Gradient_Shader::kDitherStride32) + range.fV1],
- count);
+ // Shouldn't be any need to dither for clamping?
+ sk_memset32(dstC, cache[Gradient_Shader::kCache32Count * 2], count);
}
}
@@ -1796,9 +1835,16 @@ void shadeSpan_twopoint_clamp(SkScalar fx, SkScalar dx,
for (; count > 0; --count) {
SkFixed t = two_point_radial(b, fx, fy, fSr2D2, foura,
fOneOverTwoA, posRoot);
- SkFixed index = SkClampMax(t, 0xFFFF);
- SkASSERT(index <= 0xFFFF);
- *dstC++ = cache[index >> Gradient_Shader::kCache32Shift];
+
+ if (t < 0) {
+ *dstC++ = cache[-1];
+ } else if (t > 0xFFFF) {
+ *dstC++ = cache[Gradient_Shader::kCache32Count * 2];
+ } else {
+ SkASSERT(t <= 0xFFFF);
+ *dstC++ = cache[t >> Gradient_Shader::kCache32Shift];
+ }
+
fx += dx;
fy += dy;
b += db;
--
1.7.5.4