experiment: float color components

src/core/SkShader.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkAtomics.h"
 #include "SkBitmapProcShader.h"
 #include "SkColorShader.h"
@@ skipping 99 matching lines @@
 
     fPaintAlpha = rec.fPaint->getAlpha();
 }
 
 SkShader::Context::~Context() {}
 
 SkShader::Context::ShadeProc SkShader::Context::asAShadeProc(void** ctx) {
     return nullptr;
 }
 
+void SkShader::Context::shadeSpan4f(int x, int y, SkPM4f[], int count) {
+    SkASSERT(false && "shadeSpan4f called but not implemented");
+}
+
 #include "SkColorPriv.h"
 
 #define kTempColorQuadCount 6   // balance between speed (larger) and saving stack-space
 #define kTempColorCount     (kTempColorQuadCount << 2)
 
 #ifdef SK_CPU_BENDIAN
     #define SkU32BitShiftToByteOffset(shift)    (3 - ((shift) >> 3))
 #else
     #define SkU32BitShiftToByteOffset(shift)    ((shift) >> 3)
 #endif
@@ skipping 142 matching lines @@
     unsigned g = SkColorGetG(color);
     unsigned b = SkColorGetB(color);
 
     if (a != 255) {
         r = SkMulDiv255Round(r, a);
         g = SkMulDiv255Round(g, a);
         b = SkMulDiv255Round(b, a);
     }
     fPMColor = SkPackARGB32(a, r, g, b);
 
-    fFlags = kConstInY32_Flag;
+    SkColor4f c4 = SkColor4f::FromColor(shader.fColor);
+    c4.fA *= rec.fPaint->getAlpha() / 255.0f;
+    fPM4f = c4.premul();
+
+    fFlags = kConstInY32_Flag | kSupports4f_Flag;
     if (255 == a) {
         fFlags |= kOpaqueAlpha_Flag;
     }
 }
 
 void SkColorShader::ColorShaderContext::shadeSpan(int x, int y, SkPMColor span[], int count) {
     sk_memset32(span, fPMColor, count);
 }
 
 void SkColorShader::ColorShaderContext::shadeSpanAlpha(int x, int y, uint8_t alpha[], int count) {
     memset(alpha, SkGetPackedA32(fPMColor), count);
 }
 
+void SkColorShader::ColorShaderContext::shadeSpan4f(int x, int y, SkPM4f span[], int count) {
+    for (int i = 0; i < count; ++i) {
+        span[i] = fPM4f;
+    }
+}
+
 SkShader::GradientType SkColorShader::asAGradient(GradientInfo* info) const {
     if (info) {
         if (info->fColors && info->fColorCount >= 1) {
             info->fColors[0] = fColor;
         }
         info->fColorCount = 1;
         info->fTileMode = SkShader::kRepeat_TileMode;
     }
     return kColor_GradientType;
 }
@@ skipping 34 matching lines @@
 #include "SkEmptyShader.h"
 
 void SkEmptyShader::toString(SkString* str) const {
     str->append("SkEmptyShader: (");
 
     this->INHERITED::toString(str);
 
     str->append(")");
 }
 #endif