Change SkUnitScalarClampToByte to more accurate implementation.

src/effects/GrCircleBlurFragmentProcessor.cpp

 
 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrCircleBlurFragmentProcessor.h"
 
@@ skipping 157 matching lines @@
             continue;
         }
 
         for (int x = 0; x < kernelWH; ++x) {
             float image = disk(t - kernelOff + x, -kernelOff + y, halfWidth);
             float kernel = halfKernel[y*kernelWH+x];
             acc += kernel * image;
         }
     }
 
-    return SkUnitScalarClampToByte(acc);
+    return static_cast<uint8_t>(SkTPin(acc, 0.0f, 1.0f) * 255);
 }
 
 static inline void compute_profile_offset_and_size(float halfWH, float sigma,
                                                    float* offset, int* size) {
 
     if (3*sigma <= halfWH) {
         // The circle is bigger than the Gaussian. In this case we know the interior of the
         // blurred circle is solid.
         *offset = halfWH - 3 * sigma; // This location maps to 0.5f in the weights texture.
                                       // It should always be 255.
@@ skipping 68 matching lines @@
 GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrCircleBlurFragmentProcessor);
 
 const GrFragmentProcessor* GrCircleBlurFragmentProcessor::TestCreate(GrProcessorTestData* d) {
     SkScalar wh = d->fRandom->nextRangeScalar(100.f, 1000.f);
     SkScalar sigma = d->fRandom->nextRangeF(1.f,10.f);
     SkRect circle = SkRect::MakeWH(wh, wh);
     return GrCircleBlurFragmentProcessor::Create(d->fContext->textureProvider(), circle, sigma);
 }
 
 #endif