Remove unpremul/remul from SkArithmeticMode, both raster and GPU, since the SVG spec actually defin…

src/effects/SkArithmeticMode.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkArithmeticMode.h"
 #include "SkColorPriv.h"
 #include "SkFlattenableBuffers.h"
 #include "SkString.h"
 #include "SkUnPreMultiply.h"
 #if SK_SUPPORT_GPU
 #include "GrContext.h"
 #include "gl/GrGLEffect.h"
 #include "gl/GrGLEffectMatrix.h"
 #include "GrTBackendEffectFactory.h"
 #include "SkImageFilterUtils.h"
 #endif
 
 class SkArithmeticMode_scalar : public SkXfermode {
 public:
-    SkArithmeticMode_scalar(SkScalar k1, SkScalar k2, SkScalar k3, SkScalar k4) {
+    SkArithmeticMode_scalar(SkScalar k1, SkScalar k2, SkScalar k3, SkScalar k4, bool unpremultiply) {
         fK[0] = k1;
         fK[1] = k2;
         fK[2] = k3;
         fK[3] = k4;
+        fUnpremultiply = unpremultiply;
     }
 
     virtual void xfer32(SkPMColor dst[], const SkPMColor src[], int count,
                         const SkAlpha aa[]) const SK_OVERRIDE;
 
     SK_DEVELOPER_TO_STRING()
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkArithmeticMode_scalar)
 
 #if SK_SUPPORT_GPU
     virtual bool asNewEffectOrCoeff(GrContext*, GrEffectRef** effect, Coeff*, Coeff*, GrTexture* background) const SK_OVERRIDE;
 #endif
 
 private:
     SkArithmeticMode_scalar(SkFlattenableReadBuffer& buffer) : INHERITED(buffer) {
         fK[0] = buffer.readScalar();
         fK[1] = buffer.readScalar();
         fK[2] = buffer.readScalar();
         fK[3] = buffer.readScalar();
+        fUnpremultiply = buffer.readBool();
     }
 
     virtual void flatten(SkFlattenableWriteBuffer& buffer) const SK_OVERRIDE {
         INHERITED::flatten(buffer);
         buffer.writeScalar(fK[0]);
         buffer.writeScalar(fK[1]);
         buffer.writeScalar(fK[2]);
         buffer.writeScalar(fK[3]);
+        buffer.writeBool(fUnpremultiply);
     }
     SkScalar fK[4];
+    bool fUnpremultiply;
 
     typedef SkXfermode INHERITED;
 };
 
 static int pinToByte(int value) {
     if (value < 0) {
         value = 0;
     } else if (value > 255) {
         value = 255;
     }
@@ skipping 25 matching lines @@
     SkScalar k3 = fK[2];
     SkScalar k4 = fK[3] * 255;
 
     for (int i = 0; i < count; ++i) {
         if ((NULL == aaCoverage) || aaCoverage[i]) {
             SkPMColor sc = src[i];
             SkPMColor dc = dst[i];
             int sa = SkGetPackedA32(sc);
             int da = SkGetPackedA32(dc);
 
-            int srcNeedsUnpremul = needsUnpremul(sa);
-            int dstNeedsUnpremul = needsUnpremul(da);
+            int srcNeedsUnpremul = fUnpremultiply && needsUnpremul(sa);
+            int dstNeedsUnpremul = fUnpremultiply && needsUnpremul(da);
 
             int a, r, g, b;
 
             if (!srcNeedsUnpremul && !dstNeedsUnpremul) {
                 a = arith(k1, k2, k3, k4, sa, da);
                 r = arith(k1, k2, k3, k4, SkGetPackedR32(sc), SkGetPackedR32(dc));
                 g = arith(k1, k2, k3, k4, SkGetPackedG32(sc), SkGetPackedG32(dc));
                 b = arith(k1, k2, k3, k4, SkGetPackedB32(sc), SkGetPackedB32(dc));
             } else {
                 int sr = SkGetPackedR32(sc);
@@ skipping 25 matching lines @@
             // apply antialias coverage if necessary
             if (aaCoverage && 0xFF != aaCoverage[i]) {
                 int scale = aaCoverage[i] + (aaCoverage[i] >> 7);
                 a = blend(a, SkGetPackedA32(sc), scale);
                 r = blend(r, SkGetPackedR32(sc), scale);
                 g = blend(g, SkGetPackedG32(sc), scale);
                 b = blend(b, SkGetPackedB32(sc), scale);
             }
 
             // turn the result back into premul
-            if (0xFF != a) {
+            if (fUnpremultiply && 0xFF != a) {
                 int scale = a + (a >> 7);
                 r = SkAlphaMul(r, scale);
                 g = SkAlphaMul(g, scale);
                 b = SkAlphaMul(b, scale);
             }
             dst[i] = SkPackARGB32(a, r, g, b);
         }
     }
 }
 
@@ skipping 28 matching lines @@
     x += 1 << 7;
     x >>= 8;
     return x;
 #else
     return (int32_t)(x * 256);
 #endif
 }
 #endif
 
 SkXfermode* SkArithmeticMode::Create(SkScalar k1, SkScalar k2,
-                                     SkScalar k3, SkScalar k4) {
+                                     SkScalar k3, SkScalar k4, bool unpremultiply) {
     if (fitsInBits(k1, 8) && fitsInBits(k2, 16) &&
         fitsInBits(k2, 16) && fitsInBits(k2, 24)) {
 
 #if 0 // UNUSED
         int32_t i1 = toDot8(k1);
         int32_t i2 = toDot8(k2);
         int32_t i3 = toDot8(k3);
         int32_t i4 = toDot8(k4);
         if (i1) {
             return SkNEW_ARGS(SkArithmeticMode_quad, (i1, i2, i3, i4));
         }
         if (0 == i2) {
             return SkNEW_ARGS(SkArithmeticMode_dst, (i3, i4));
         }
         if (0 == i3) {
             return SkNEW_ARGS(SkArithmeticMode_src, (i2, i4));
         }
         return SkNEW_ARGS(SkArithmeticMode_linear, (i2, i3, i4));
 #endif
     }
-    return SkNEW_ARGS(SkArithmeticMode_scalar, (k1, k2, k3, k4));
+    return SkNEW_ARGS(SkArithmeticMode_scalar, (k1, k2, k3, k4, unpremultiply));
 }
 
 
 //////////////////////////////////////////////////////////////////////////////
 
 #if SK_SUPPORT_GPU
 
 class GrGLArithmeticEffect : public GrGLEffect {
 public:
     GrGLArithmeticEffect(const GrBackendEffectFactory&, const GrDrawEffect&);
@@ skipping 15 matching lines @@
     GrGLEffectMatrix fBackgroundEffectMatrix;
     GrGLUniformManager::UniformHandle fKUni;
 
     typedef GrGLEffect INHERITED;
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
 class GrArithmeticEffect : public GrEffect {
 public:
-    static GrEffectRef* Create(float k1, float k2, float k3, float k4, GrTexture* background) {
-        AutoEffectUnref effect(SkNEW_ARGS(GrArithmeticEffect, (k1, k2, k3, k4, background)));
+    static GrEffectRef* Create(float k1, float k2, float k3, float k4, bool unpremultiply, GrTexture* background) {
+        AutoEffectUnref effect(SkNEW_ARGS(GrArithmeticEffect, (k1, k2, k3, k4, unpremultiply, background)));
         return CreateEffectRef(effect);
     }
 
     virtual ~GrArithmeticEffect();
 
     virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE;
 
     typedef GrGLArithmeticEffect GLEffect;
     static const char* Name() { return "Arithmetic"; }
     GrTexture* backgroundTexture() const { return fBackgroundAccess.getTexture(); }
 
     virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE;
 
     float k1() const { return fK1; }
     float k2() const { return fK2; }
     float k3() const { return fK3; }
     float k4() const { return fK4; }
+    bool unpremultiply() const { return fUnpremultiply; }
 
 private:
     virtual bool onIsEqual(const GrEffect&) const SK_OVERRIDE;
 
-    GrArithmeticEffect(float k1, float k2, float k3, float k4, GrTexture* background);
+    GrArithmeticEffect(float k1, float k2, float k3, float k4, bool unpremultiply, GrTexture* background);
     float                       fK1, fK2, fK3, fK4;
+    bool                        fUnpremultiply;
     GrTextureAccess             fBackgroundAccess;
 
     GR_DECLARE_EFFECT_TEST;
     typedef GrEffect INHERITED;
 
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
 GrArithmeticEffect::GrArithmeticEffect(float k1, float k2, float k3, float k4,
-                                       GrTexture* background)
-  : fK1(k1), fK2(k2), fK3(k3), fK4(k4) {
+                                       bool unpremultiply, GrTexture* background)
+  : fK1(k1), fK2(k2), fK3(k3), fK4(k4), fUnpremultiply(unpremultiply) {
     if (background) {
         fBackgroundAccess.reset(background);
         this->addTextureAccess(&fBackgroundAccess);
     } else {
         this->setWillReadDstColor();
     }
 }
 
 GrArithmeticEffect::~GrArithmeticEffect() {
 }
 
 bool GrArithmeticEffect::onIsEqual(const GrEffect& sBase) const {
     const GrArithmeticEffect& s = CastEffect<GrArithmeticEffect>(sBase);
     return fK1 == s.fK1 &&
            fK2 == s.fK2 &&
            fK3 == s.fK3 &&
            fK4 == s.fK4 &&
+           fUnpremultiply == s.fUnpremultiply &&
            backgroundTexture() == s.backgroundTexture();
 }
 
 const GrBackendEffectFactory& GrArithmeticEffect::getFactory() const {
     return GrTBackendEffectFactory<GrArithmeticEffect>::getInstance();
 }
 
 void GrArithmeticEffect::getConstantColorComponents(GrColor* color, uint32_t* validFlags) const {
     // TODO: optimize this
     *validFlags = 0;
@@ skipping 10 matching lines @@
 GrGLArithmeticEffect::~GrGLArithmeticEffect() {
 }
 
 void GrGLArithmeticEffect::emitCode(GrGLShaderBuilder* builder,
                                     const GrDrawEffect& drawEffect,
                                     EffectKey key,
                                     const char* outputColor,
                                     const char* inputColor,
                                     const TextureSamplerArray& samplers) {
 
-    GrTexture* backgroundTex = drawEffect.castEffect<GrArithmeticEffect>().backgroundTexture();
+    const GrArithmeticEffect& arith = drawEffect.castEffect<GrArithmeticEffect>();
+    GrTexture* backgroundTex = arith.backgroundTexture();
+    bool unpremultiply = arith.unpremultiply();
     const char* dstColor;
     if (backgroundTex) {
         const char* bgCoords;
         GrSLType bgCoordsType = fBackgroundEffectMatrix.emitCode(builder, key, &bgCoords, NULL, "BG");
         builder->fsCodeAppend("\t\tvec4 bgColor = ");
         builder->appendTextureLookup(GrGLShaderBuilder::kFragment_ShaderType,
                                      samplers[0],
                                      bgCoords,
                                      bgCoordsType);
         builder->fsCodeAppendf(";\n");
         dstColor = "bgColor";
     } else {
         dstColor = builder->dstColor();
     }
 
     GrAssert(NULL != dstColor);
     fKUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
                                 kVec4f_GrSLType, "k");
     const char* kUni = builder->getUniformCStr(fKUni);
 
     // We don't try to optimize for this case at all
     if (NULL == inputColor) {
         builder->fsCodeAppendf("\t\tconst vec4 src = %s;\n", GrGLSLOnesVecf(4));
     } else {
         builder->fsCodeAppendf("\t\tvec4 src = %s;\n", inputColor);
-        builder->fsCodeAppendf("\t\tsrc.rgb = clamp(src.rgb / src.a, 0.0, 1.0);\n");
+        if (unpremultiply) {
+            builder->fsCodeAppendf("\t\tsrc.rgb = clamp(src.rgb / src.a, 0.0, 1.0);\n");
+        }
     }
 
     builder->fsCodeAppendf("\t\tvec4 dst = %s;\n", dstColor);
-    builder->fsCodeAppendf("\t\tdst.rgb = clamp(dst.rgb / dst.a, 0.0, 1.0);\n");
+    if (unpremultiply) {
+        builder->fsCodeAppendf("\t\tdst.rgb = clamp(dst.rgb / dst.a, 0.0, 1.0);\n");
+    }
 
     builder->fsCodeAppendf("\t\t%s = %s.x * src * dst + %s.y * src + %s.z * dst + %s.w;\n", outputColor, kUni, kUni, kUni, kUni);
     builder->fsCodeAppendf("\t\t%s = clamp(%s, 0.0, 1.0);\n", outputColor, outputColor);
-    builder->fsCodeAppendf("\t\t%s.rgb *= %s.a;\n", outputColor, outputColor);
+    if (unpremultiply) {
+        builder->fsCodeAppendf("\t\t%s.rgb *= %s.a;\n", outputColor, outputColor);
+    } else {
+        builder->fsCodeAppendf("\t\t%s.rgb = min(%s.rgb, %s.a);\n", outputColor, outputColor, outputColor);
+    }
 }
 
 void GrGLArithmeticEffect::setData(const GrGLUniformManager& uman, const GrDrawEffect& drawEffect) {
     const GrArithmeticEffect& arith = drawEffect.castEffect<GrArithmeticEffect>();
     uman.set4f(fKUni, arith.k1(), arith.k2(), arith.k3(), arith.k4());
     GrTexture* bgTex = arith.backgroundTexture();
     if (bgTex) {
         fBackgroundEffectMatrix.setData(uman,
                                         GrEffect::MakeDivByTextureWHMatrix(bgTex),
                                         drawEffect,
                                         bgTex);
     }
 }
 
 GrGLEffect::EffectKey GrGLArithmeticEffect::GenKey(const GrDrawEffect& drawEffect, const GrGLCaps&) {
     const GrArithmeticEffect& effect = drawEffect.castEffect<GrArithmeticEffect>();
     GrTexture* bgTex = effect.backgroundTexture();
     EffectKey bgKey = 0;
     if (bgTex) {
         bgKey = GrGLEffectMatrix::GenKey(GrEffect::MakeDivByTextureWHMatrix(bgTex),
                                          drawEffect,
                                          GrGLArithmeticEffect::kCoordsType,
                                          bgTex);
     }
-    return bgKey;
+    EffectKey unpremulKey = (effect.unpremultiply() ? 0x1 : 0x0) << GrGLEffectMatrix::kKeyBits;
+    return unpremulKey | bgKey;
 }
 
 GrEffectRef* GrArithmeticEffect::TestCreate(SkMWCRandom* rand,
                                             GrContext*,
                                             const GrDrawTargetCaps&,
                                             GrTexture*[]) {
     float k1 = rand->nextF();
     float k2 = rand->nextF();
     float k3 = rand->nextF();
     float k4 = rand->nextF();
+    bool unpremultiply = rand->nextBool();
 
-    static AutoEffectUnref gEffect(SkNEW_ARGS(GrArithmeticEffect, (k1, k2, k3, k4, NULL)));
+    static AutoEffectUnref gEffect(SkNEW_ARGS(GrArithmeticEffect, (k1, k2, k3, k4, unpremultiply, NULL)));
     return CreateEffectRef(gEffect);
 }
 
 GR_DEFINE_EFFECT_TEST(GrArithmeticEffect);
 
 bool SkArithmeticMode_scalar::asNewEffectOrCoeff(GrContext*,
                                                  GrEffectRef** effect,
                                                  Coeff*,
                                                  Coeff*,
                                                  GrTexture* background) const {
     if (effect) {
         *effect = GrArithmeticEffect::Create(SkScalarToFloat(fK[0]),
                                              SkScalarToFloat(fK[1]),
                                              SkScalarToFloat(fK[2]),
                                              SkScalarToFloat(fK[3]),
+                                             fUnpremultiply,
                                              background);
     }
     return true;
 }
 
 #endif
 
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_START(SkArithmeticMode)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkArithmeticMode_scalar)
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_END