Add dest type hint to SkShader::ContextRec

src/core/SkBlitter.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 "SkBlitter.h"
 #include "SkAntiRun.h"
 #include "SkColor.h"
@@ skipping 771 matching lines @@
 private:
     // Both pointers are unowned. They will be deleted by SkSmallAllocator.
     SkBlitter*          fProxy;
     SkShader::Context*  fShaderContext;
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
 #include "SkCoreBlitters.h"
 
+SkShader::ContextRec::DstType SkBlitter::PreferredShaderDest(const SkImageInfo& dstInfo) {
+#ifdef SK_FORCE_PM4f_FOR_L32_BLITS
+    return SkShader::ContextRec::kPM4f_DstType;
+#else
+    return (dstInfo.isSRGB() || dstInfo.colorType() == kRGBA_F16_SkColorType)
+            ? SkShader::ContextRec::kPM4f_DstType
+            : SkShader::ContextRec::kPMColor_DstType;
+#endif
+}
+
 SkBlitter* SkBlitter::Choose(const SkPixmap& device,
                              const SkMatrix& matrix,
                              const SkPaint& origPaint,
                              SkTBlitterAllocator* allocator,
                              bool drawCoverage) {
     SkASSERT(allocator != nullptr);
 
     // which check, in case we're being called by a client with a dummy device
     // (e.g. they have a bounder that always aborts the draw)
     if (kUnknown_SkColorType == device.colorType() ||
@@ skipping 66 matching lines @@
         paint.writable()->setShader(shader)->unref();
         // blitters should ignore the presence/absence of a filter, since
         // if there is one, the shader will take care of it.
     }
 
     /*
      *  We create a SkShader::Context object, and store it on the blitter.
      */
     SkShader::Context* shaderContext = nullptr;
     if (shader) {
-        SkShader::ContextRec rec(*paint, matrix, nullptr);
+        const SkShader::ContextRec rec(*paint, matrix, nullptr,
+                                       PreferredShaderDest(device.info()));
         size_t contextSize = shader->contextSize(rec);
         if (contextSize) {
             // Try to create the ShaderContext
             void* storage = allocator->reserveT<SkShader::Context>(contextSize);
             shaderContext = shader->createContext(rec, storage);
             if (!shaderContext) {
                 allocator->freeLast();
                 return allocator->createT<SkNullBlitter>();
             }
             SkASSERT(shaderContext);
@@ skipping 65 matching lines @@
     }
     return blitter;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 class SkZeroShaderContext : public SkShader::Context {
 public:
     SkZeroShaderContext(const SkShader& shader, const SkShader::ContextRec& rec)
         // Override rec with the identity matrix, so it is guaranteed to be invertible.
-        : INHERITED(shader, SkShader::ContextRec(*rec.fPaint, SkMatrix::I(), nullptr)) {}
+        : INHERITED(shader, SkShader::ContextRec(*rec.fPaint, SkMatrix::I(), nullptr,
+                                                 rec.fPreferredDstType)) {}
 
     void shadeSpan(int x, int y, SkPMColor colors[], int count) override {
         sk_bzero(colors, count * sizeof(SkPMColor));
     }
 
 private:
     typedef SkShader::Context INHERITED;
 };
 
 SkShaderBlitter::SkShaderBlitter(const SkPixmap& device, const SkPaint& paint,
@@ skipping 22 matching lines @@
     fShaderContext->~Context();
     SkShader::Context* ctx = fShader->createContext(rec, (void*)fShaderContext);
     if (nullptr == ctx) {
         // Need a valid context in fShaderContext's storage, so we can later (or our caller) call
         // the in-place destructor.
         new (fShaderContext) SkZeroShaderContext(*fShader, rec);
         return false;
     }
     return true;
 }