The Tor Browser: gfx/skia/trunk/src/effects/gradients/SkLinearGradient.cpp@b8a032363ba2 (annotated)

gfx/skia/trunk/src/effects/gradients/SkLinearGradient.cpp@b8a032363ba2 (annotated)

gfx/skia/trunk/src/effects/gradients/SkLinearGradient.cpp

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "SkLinearGradient.h"
 static inline int repeat_bits(int x, const int bits) {
     return x & ((1 << bits) - 1);
 }
 static inline int repeat_8bits(int x) {
     return x & 0xFF;
 }
 // Visual Studio 2010 (MSC_VER=1600) optimizes bit-shift code incorrectly.
 // See http://code.google.com/p/skia/issues/detail?id=472
 #if defined(_MSC_VER) && (_MSC_VER >= 1600)
 #pragma optimize("", off)
 #endif
 static inline int mirror_bits(int x, const int bits) {
     if (x & (1 << bits)) {
         x = ~x;
     }
     return x & ((1 << bits) - 1);
 }
 static inline int mirror_8bits(int x) {
     if (x & 256) {
         x = ~x;
     }
     return x & 255;
 }
 #if defined(_MSC_VER) && (_MSC_VER >= 1600)
 #pragma optimize("", on)
 #endif
 static void pts_to_unit_matrix(const SkPoint pts[2], SkMatrix* matrix) {
     SkVector    vec = pts[1] - pts[0];
     SkScalar    mag = vec.length();
     SkScalar    inv = mag ? SkScalarInvert(mag) : 0;
     vec.scale(inv);
     matrix->setSinCos(-vec.fY, vec.fX, pts[0].fX, pts[0].fY);
     matrix->postTranslate(-pts[0].fX, -pts[0].fY);
     matrix->postScale(inv, inv);
 }
 ///////////////////////////////////////////////////////////////////////////////
 SkLinearGradient::SkLinearGradient(const SkPoint pts[2], const Descriptor& desc)
     : SkGradientShaderBase(desc)
     , fStart(pts[0])
     , fEnd(pts[1]) {
     pts_to_unit_matrix(pts, &fPtsToUnit);
 }
 SkLinearGradient::SkLinearGradient(SkReadBuffer& buffer)
     : INHERITED(buffer)
     , fStart(buffer.readPoint())
     , fEnd(buffer.readPoint()) {
 }
 void SkLinearGradient::flatten(SkWriteBuffer& buffer) const {
     this->INHERITED::flatten(buffer);
     buffer.writePoint(fStart);
     buffer.writePoint(fEnd);
 }
 bool SkLinearGradient::setContext(const SkBitmap& device, const SkPaint& paint,
                                  const SkMatrix& matrix) {
     if (!this->INHERITED::setContext(device, paint, matrix)) {
         return false;
     }
     unsigned mask = SkMatrix::kTranslate_Mask | SkMatrix::kScale_Mask;
     if ((fDstToIndex.getType() & ~mask) == 0) {
         // when we dither, we are (usually) not const-in-Y
         if ((fFlags & SkShader::kHasSpan16_Flag) && !paint.isDither()) {
             // only claim this if we do have a 16bit mode (i.e. none of our
             // colors have alpha), and if we are not dithering (which obviously
             // is not const in Y).
             fFlags |= SkShader::kConstInY16_Flag;
         }
     }
     return true;
 }
 #define NO_CHECK_ITER               \
     do {                            \
     unsigned fi = fx >> SkGradientShaderBase::kCache32Shift; \
     SkASSERT(fi <= 0xFF);           \
     fx += dx;                       \
     *dstC++ = cache[toggle + fi];   \
     toggle = next_dither_toggle(toggle); \
     } while (0)
 namespace {
 typedef void (*LinearShadeProc)(TileProc proc, SkFixed dx, SkFixed fx,
                                 SkPMColor* dstC, const SkPMColor* cache,
                                 int toggle, int count);
 // Linear interpolation (lerp) is unnecessary if there are no sharp
 // discontinuities in the gradient - which must be true if there are
 // only 2 colors - but it's cheap.
 void shadeSpan_linear_vertical_lerp(TileProc proc, SkFixed dx, SkFixed fx,
                                     SkPMColor* SK_RESTRICT dstC,
                                     const SkPMColor* SK_RESTRICT cache,
                                     int toggle, int count) {
     // 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.
     unsigned fullIndex = proc(fx);
     unsigned fi = fullIndex >> SkGradientShaderBase::kCache32Shift;
     unsigned remainder = fullIndex & ((1 << SkGradientShaderBase::kCache32Shift) - 1);
     int index0 = fi + toggle;
     int index1 = index0;
     if (fi < SkGradientShaderBase::kCache32Count - 1) {
         index1 += 1;
     }
     SkPMColor lerp = SkFastFourByteInterp(cache[index1], cache[index0], remainder);
     index0 ^= SkGradientShaderBase::kDitherStride32;
     index1 ^= SkGradientShaderBase::kDitherStride32;
     SkPMColor dlerp = SkFastFourByteInterp(cache[index1], cache[index0], remainder);
     sk_memset32_dither(dstC, lerp, dlerp, count);
 }
 void shadeSpan_linear_clamp(TileProc proc, SkFixed dx, SkFixed fx,
                             SkPMColor* SK_RESTRICT dstC,
                             const SkPMColor* SK_RESTRICT cache,
                             int toggle, int count) {
     SkClampRange range;
     range.init(fx, dx, count, 0, SkGradientShaderBase::kCache32Count - 1);
     if ((count = range.fCount0) > 0) {
         sk_memset32_dither(dstC,
             cache[toggle + range.fV0],
             cache[next_dither_toggle(toggle) + range.fV0],
             count);
         dstC += count;
     }
     if ((count = range.fCount1) > 0) {
         int unroll = count >> 3;
         fx = range.fFx1;
         for (int i = 0; i < unroll; i++) {
             NO_CHECK_ITER;  NO_CHECK_ITER;
             NO_CHECK_ITER;  NO_CHECK_ITER;
             NO_CHECK_ITER;  NO_CHECK_ITER;
             NO_CHECK_ITER;  NO_CHECK_ITER;
         }
         if ((count &= 7) > 0) {
             do {
                 NO_CHECK_ITER;
             } while (--count != 0);
         }
     }
     if ((count = range.fCount2) > 0) {
         sk_memset32_dither(dstC,
             cache[toggle + range.fV1],
             cache[next_dither_toggle(toggle) + range.fV1],
             count);
     }
 }
 void shadeSpan_linear_mirror(TileProc proc, SkFixed dx, SkFixed fx,
                              SkPMColor* SK_RESTRICT dstC,
                              const SkPMColor* SK_RESTRICT cache,
                              int toggle, int count) {
     do {
         unsigned fi = mirror_8bits(fx >> 8);
         SkASSERT(fi <= 0xFF);
         fx += dx;
         *dstC++ = cache[toggle + fi];
         toggle = next_dither_toggle(toggle);
     } while (--count != 0);
 }
 void shadeSpan_linear_repeat(TileProc proc, SkFixed dx, SkFixed fx,
         SkPMColor* SK_RESTRICT dstC,
         const SkPMColor* SK_RESTRICT cache,
         int toggle, int count) {
     do {
         unsigned fi = repeat_8bits(fx >> 8);
         SkASSERT(fi <= 0xFF);
         fx += dx;
         *dstC++ = cache[toggle + fi];
         toggle = next_dither_toggle(toggle);
     } while (--count != 0);
 }
 }
 void SkLinearGradient::shadeSpan(int x, int y, SkPMColor* SK_RESTRICT dstC,
                                 int count) {
     SkASSERT(count > 0);
     SkPoint             srcPt;
     SkMatrix::MapXYProc dstProc = fDstToIndexProc;
     TileProc            proc = fTileProc;
     const SkPMColor* SK_RESTRICT cache = this->getCache32();
     int                 toggle = init_dither_toggle(x, y);
     if (fDstToIndexClass != kPerspective_MatrixClass) {
         dstProc(fDstToIndex, SkIntToScalar(x) + SK_ScalarHalf,
                              SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
         SkFixed dx, fx = SkScalarToFixed(srcPt.fX);
         if (fDstToIndexClass == kFixedStepInX_MatrixClass) {
             SkFixed dxStorage[1];
             (void)fDstToIndex.fixedStepInX(SkIntToScalar(y), dxStorage, NULL);
             dx = dxStorage[0];
         } else {
             SkASSERT(fDstToIndexClass == kLinear_MatrixClass);
             dx = SkScalarToFixed(fDstToIndex.getScaleX());
         }
         LinearShadeProc shadeProc = shadeSpan_linear_repeat;
         if (0 == dx) {
             shadeProc = shadeSpan_linear_vertical_lerp;
         } else if (SkShader::kClamp_TileMode == fTileMode) {
             shadeProc = shadeSpan_linear_clamp;
         } else if (SkShader::kMirror_TileMode == fTileMode) {
             shadeProc = shadeSpan_linear_mirror;
         } else {
             SkASSERT(SkShader::kRepeat_TileMode == fTileMode);
         }
         (*shadeProc)(proc, dx, fx, dstC, cache, toggle, count);
     } else {
         SkScalar    dstX = SkIntToScalar(x);
         SkScalar    dstY = SkIntToScalar(y);
         do {
             dstProc(fDstToIndex, dstX, dstY, &srcPt);
             unsigned fi = proc(SkScalarToFixed(srcPt.fX));
             SkASSERT(fi <= 0xFFFF);
             *dstC++ = cache[toggle + (fi >> kCache32Shift)];
             toggle = next_dither_toggle(toggle);
             dstX += SK_Scalar1;
         } while (--count != 0);
     }
 }
 SkShader::BitmapType SkLinearGradient::asABitmap(SkBitmap* bitmap,
                                                 SkMatrix* matrix,
                                                 TileMode xy[]) const {
     if (bitmap) {
         this->getGradientTableBitmap(bitmap);
     }
     if (matrix) {
         matrix->preConcat(fPtsToUnit);
     }
     if (xy) {
         xy[0] = fTileMode;
         xy[1] = kClamp_TileMode;
     }
     return kLinear_BitmapType;
 }
 SkShader::GradientType SkLinearGradient::asAGradient(GradientInfo* info) const {
     if (info) {
         commonAsAGradient(info);
         info->fPoint[0] = fStart;
         info->fPoint[1] = fEnd;
     }
     return kLinear_GradientType;
 }
 static void dither_memset16(uint16_t dst[], uint16_t value, uint16_t other,
                             int count) {
     if (reinterpret_cast<uintptr_t>(dst) & 2) {
         *dst++ = value;
         count -= 1;
         SkTSwap(value, other);
     }
     sk_memset32((uint32_t*)dst, (value << 16) | other, count >> 1);
     if (count & 1) {
         dst[count - 1] = value;
     }
 }
 #define NO_CHECK_ITER_16                \
     do {                                \
     unsigned fi = fx >> SkGradientShaderBase::kCache16Shift;  \
     SkASSERT(fi < SkGradientShaderBase::kCache16Count);       \
     fx += dx;                           \
     *dstC++ = cache[toggle + fi];       \
     toggle = next_dither_toggle16(toggle);            \
     } while (0)
 namespace {
 typedef void (*LinearShade16Proc)(TileProc proc, SkFixed dx, SkFixed fx,
                                   uint16_t* dstC, const uint16_t* cache,
                                   int toggle, int count);
 void shadeSpan16_linear_vertical(TileProc proc, SkFixed dx, SkFixed fx,
                                  uint16_t* SK_RESTRICT dstC,
                                  const uint16_t* SK_RESTRICT cache,
                                  int toggle, int count) {
     // we're a vertical gradient, so no change in a span
     unsigned fi = proc(fx) >> SkGradientShaderBase::kCache16Shift;
     SkASSERT(fi < SkGradientShaderBase::kCache16Count);
     dither_memset16(dstC, cache[toggle + fi],
         cache[next_dither_toggle16(toggle) + fi], count);
 }
 void shadeSpan16_linear_clamp(TileProc proc, SkFixed dx, SkFixed fx,
                               uint16_t* SK_RESTRICT dstC,
                               const uint16_t* SK_RESTRICT cache,
                               int toggle, int count) {
     SkClampRange range;
     range.init(fx, dx, count, 0, SkGradientShaderBase::kCache32Count - 1);
     if ((count = range.fCount0) > 0) {
         dither_memset16(dstC,
             cache[toggle + range.fV0],
             cache[next_dither_toggle16(toggle) + range.fV0],
             count);
         dstC += count;
     }
     if ((count = range.fCount1) > 0) {
         int unroll = count >> 3;
         fx = range.fFx1;
         for (int i = 0; i < unroll; i++) {
             NO_CHECK_ITER_16;  NO_CHECK_ITER_16;
             NO_CHECK_ITER_16;  NO_CHECK_ITER_16;
             NO_CHECK_ITER_16;  NO_CHECK_ITER_16;
             NO_CHECK_ITER_16;  NO_CHECK_ITER_16;
         }
         if ((count &= 7) > 0) {
             do {
                 NO_CHECK_ITER_16;
             } while (--count != 0);
         }
     }
     if ((count = range.fCount2) > 0) {
         dither_memset16(dstC,
             cache[toggle + range.fV1],
             cache[next_dither_toggle16(toggle) + range.fV1],
             count);
     }
 }
 void shadeSpan16_linear_mirror(TileProc proc, SkFixed dx, SkFixed fx,
                                uint16_t* SK_RESTRICT dstC,
                                const uint16_t* SK_RESTRICT cache,
                                int toggle, int count) {
     do {
         unsigned fi = mirror_bits(fx >> SkGradientShaderBase::kCache16Shift,
                                         SkGradientShaderBase::kCache16Bits);
         SkASSERT(fi < SkGradientShaderBase::kCache16Count);
         fx += dx;
         *dstC++ = cache[toggle + fi];
         toggle = next_dither_toggle16(toggle);
     } while (--count != 0);
 }
 void shadeSpan16_linear_repeat(TileProc proc, SkFixed dx, SkFixed fx,
                                uint16_t* SK_RESTRICT dstC,
                                const uint16_t* SK_RESTRICT cache,
                                int toggle, int count) {
     do {
         unsigned fi = repeat_bits(fx >> SkGradientShaderBase::kCache16Shift,
                                   SkGradientShaderBase::kCache16Bits);
         SkASSERT(fi < SkGradientShaderBase::kCache16Count);
         fx += dx;
         *dstC++ = cache[toggle + fi];
         toggle = next_dither_toggle16(toggle);
     } while (--count != 0);
 }
 }
 static bool fixed_nearly_zero(SkFixed x) {
     return SkAbs32(x) < (SK_Fixed1 >> 12);
 }
 void SkLinearGradient::shadeSpan16(int x, int y,
                                   uint16_t* SK_RESTRICT dstC, int count) {
     SkASSERT(count > 0);
     SkPoint             srcPt;
     SkMatrix::MapXYProc dstProc = fDstToIndexProc;
     TileProc            proc = fTileProc;
     const uint16_t* SK_RESTRICT cache = this->getCache16();
     int                 toggle = init_dither_toggle16(x, y);
     if (fDstToIndexClass != kPerspective_MatrixClass) {
         dstProc(fDstToIndex, SkIntToScalar(x) + SK_ScalarHalf,
                              SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
         SkFixed dx, fx = SkScalarToFixed(srcPt.fX);
         if (fDstToIndexClass == kFixedStepInX_MatrixClass) {
             SkFixed dxStorage[1];
             (void)fDstToIndex.fixedStepInX(SkIntToScalar(y), dxStorage, NULL);
             dx = dxStorage[0];
         } else {
             SkASSERT(fDstToIndexClass == kLinear_MatrixClass);
             dx = SkScalarToFixed(fDstToIndex.getScaleX());
         }
         LinearShade16Proc shadeProc = shadeSpan16_linear_repeat;
         if (fixed_nearly_zero(dx)) {
             shadeProc = shadeSpan16_linear_vertical;
         } else if (SkShader::kClamp_TileMode == fTileMode) {
             shadeProc = shadeSpan16_linear_clamp;
         } else if (SkShader::kMirror_TileMode == fTileMode) {
             shadeProc = shadeSpan16_linear_mirror;
         } else {
             SkASSERT(SkShader::kRepeat_TileMode == fTileMode);
         }
         (*shadeProc)(proc, dx, fx, dstC, cache, toggle, count);
     } else {
         SkScalar    dstX = SkIntToScalar(x);
         SkScalar    dstY = SkIntToScalar(y);
         do {
             dstProc(fDstToIndex, dstX, dstY, &srcPt);
             unsigned fi = proc(SkScalarToFixed(srcPt.fX));
             SkASSERT(fi <= 0xFFFF);
             int index = fi >> kCache16Shift;
             *dstC++ = cache[toggle + index];
             toggle = next_dither_toggle16(toggle);
             dstX += SK_Scalar1;
         } while (--count != 0);
     }
 }
 #if SK_SUPPORT_GPU
 #include "GrTBackendEffectFactory.h"
 /////////////////////////////////////////////////////////////////////
 class GrGLLinearGradient : public GrGLGradientEffect {
 public:
     GrGLLinearGradient(const GrBackendEffectFactory& factory, const GrDrawEffect&)
                        : INHERITED (factory) { }
     virtual ~GrGLLinearGradient() { }
     virtual void emitCode(GrGLShaderBuilder*,
                           const GrDrawEffect&,
                           EffectKey,
                           const char* outputColor,
                           const char* inputColor,
                           const TransformedCoordsArray&,
                           const TextureSamplerArray&) SK_OVERRIDE;
     static EffectKey GenKey(const GrDrawEffect& drawEffect, const GrGLCaps&) {
         return GenBaseGradientKey(drawEffect);
     }
 private:
     typedef GrGLGradientEffect INHERITED;
 };
 /////////////////////////////////////////////////////////////////////
 class GrLinearGradient : public GrGradientEffect {
 public:
     static GrEffectRef* Create(GrContext* ctx,
                                const SkLinearGradient& shader,
                                const SkMatrix& matrix,
                                SkShader::TileMode tm) {
         AutoEffectUnref effect(SkNEW_ARGS(GrLinearGradient, (ctx, shader, matrix, tm)));
         return CreateEffectRef(effect);
     }
     virtual ~GrLinearGradient() { }
     static const char* Name() { return "Linear Gradient"; }
     const GrBackendEffectFactory& getFactory() const SK_OVERRIDE {
         return GrTBackendEffectFactory<GrLinearGradient>::getInstance();
     }
     typedef GrGLLinearGradient GLEffect;
 private:
     GrLinearGradient(GrContext* ctx,
                      const SkLinearGradient& shader,
                      const SkMatrix& matrix,
                      SkShader::TileMode tm)
         : INHERITED(ctx, shader, matrix, tm) { }
     GR_DECLARE_EFFECT_TEST;
     typedef GrGradientEffect INHERITED;
 };
 /////////////////////////////////////////////////////////////////////
 GR_DEFINE_EFFECT_TEST(GrLinearGradient);
 GrEffectRef* GrLinearGradient::TestCreate(SkRandom* random,
                                           GrContext* context,
                                           const GrDrawTargetCaps&,
                                           GrTexture**) {
     SkPoint points[] = {{random->nextUScalar1(), random->nextUScalar1()},
                         {random->nextUScalar1(), random->nextUScalar1()}};
     SkColor colors[kMaxRandomGradientColors];
     SkScalar stopsArray[kMaxRandomGradientColors];
     SkScalar* stops = stopsArray;
     SkShader::TileMode tm;
     int colorCount = RandomGradientParams(random, colors, &stops, &tm);
     SkAutoTUnref<SkShader> shader(SkGradientShader::CreateLinear(points,
                                                                  colors, stops, colorCount,
                                                                  tm));
     SkPaint paint;
     return shader->asNewEffect(context, paint);
 }
 /////////////////////////////////////////////////////////////////////
 void GrGLLinearGradient::emitCode(GrGLShaderBuilder* builder,
                                   const GrDrawEffect&,
                                   EffectKey key,
                                   const char* outputColor,
                                   const char* inputColor,
                                   const TransformedCoordsArray& coords,
                                   const TextureSamplerArray& samplers) {
     this->emitUniforms(builder, key);
     SkString t = builder->ensureFSCoords2D(coords, 0);
     t.append(".x");
     this->emitColor(builder, t.c_str(), key, outputColor, inputColor, samplers);
 }
 /////////////////////////////////////////////////////////////////////
 GrEffectRef* SkLinearGradient::asNewEffect(GrContext* context, const SkPaint&) const {
     SkASSERT(NULL != context);
     SkMatrix matrix;
     if (!this->getLocalMatrix().invert(&matrix)) {
         return NULL;
     }
     matrix.postConcat(fPtsToUnit);
     return GrLinearGradient::Create(context, *this, matrix, fTileMode);
 }
 #else
 GrEffectRef* SkLinearGradient::asNewEffect(GrContext*, const SkPaint&) const {
     SkDEBUGFAIL("Should not call in GPU-less build");
     return NULL;
 }
 #endif
 #ifndef SK_IGNORE_TO_STRING
 void SkLinearGradient::toString(SkString* str) const {
     str->append("SkLinearGradient (");
     str->appendf("start: (%f, %f)", fStart.fX, fStart.fY);
     str->appendf(" end: (%f, %f) ", fEnd.fX, fEnd.fY);
     this->INHERITED::toString(str);
     str->append(")");
 }
 #endif

The Tor Browser / annotate

gfx/skia/trunk/src/effects/gradients/SkLinearGradient.cpp@b8a032363ba2 (annotated)

gfx/skia/trunk/src/effects/gradients/SkLinearGradient.cpp