First blitter for linear pipeline.

src/core/SkLinearBitmapPipeline.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkLinearBitmapPipeline.h"
 
 #include "SkPM4f.h"
@@ skipping 758 matching lines @@
     // As the stages are built, the chooser function may skip a stage. For example, with the
     // identity matrix, the matrix stage is skipped, and the tilerStage is the first stage.
     auto blenderStage = choose_blender(alphaType, postAlpha, &fBlenderStage);
     auto samplerStage = choose_pixel_sampler(blenderStage, filterQuality, srcPixmap, &fSampleStage);
     auto tilerStage   = choose_tiler(samplerStage, dimensions, xTile, yTile,
                                      filterQuality, dx, &fTileStage);
     fFirstStage       = choose_matrix(tilerStage, adjustedInverse, &fMatrixStage);
     fLastStage        = blenderStage;
 }
 
+SkLinearBitmapPipeline::SkLinearBitmapPipeline(
+    const SkLinearBitmapPipeline& pipeline,
+    SkXfermode::Mode mode,
+    const SkPixmap& srcPixmap,
+    const SkImageInfo& dstInfo)
+{
+    SkASSERT(mode == SkXfermode::kSrc_Mode);
+    SkASSERT(srcPixmap.info().colorType() == dstInfo.colorType()
+             && srcPixmap.info().colorType() == kRGBA_8888_SkColorType);
+
+    fSampleStage.initSink<RGBA8888UnitRepeat>(srcPixmap.writable_addr32(0, 0), srcPixmap.width());
+    auto sampleStage = fSampleStage.get();
+    auto tilerStage = pipeline.fTileStage.cloneStageTo(sampleStage, &fTileStage);
+    tilerStage = (tilerStage != nullptr) ? tilerStage : sampleStage;
+    auto matrixStage = pipeline.fMatrixStage.cloneStageTo(tilerStage, &fMatrixStage);
+    matrixStage = (matrixStage != nullptr) ? matrixStage : tilerStage;
+    fFirstStage = matrixStage;
+    fLastStage = fSampleStage.getInterface<DestinationInterface, RGBA8888UnitRepeat>();
+}

[mtklein, 2016/04/11 16:43:25]

It is weird that we've constructed an object here where it's sensible to call
blitSpan() but not shadeSpan4f().

[herb_g, 2016/04/12 20:03:49]

I think that shadeSpan4f will go away as we restructure higher levels of the
code.

+
 void SkLinearBitmapPipeline::shadeSpan4f(int x, int y, SkPM4f* dst, int count) {
     SkASSERT(count > 0);
+    this->blitSpan(x, y, dst, count);
+}
+
+void SkLinearBitmapPipeline::blitSpan(int x, int y, void* dst, int count) {
+    SkASSERT(count > 0);
     fLastStage->setDestination(dst, count);
 
     // The count and length arguments start out in a precise relation in order to keep the
     // math correct through the different stages. Count is the number of pixel to produce.
     // Since the code samples at pixel centers, length is the distance from the center of the
     // first pixel to the center of the last pixel. This implies that length is count-1.
     fFirstStage->pointSpan(Span{{x + 0.5f, y + 0.5f}, count - 1.0f, count});
 }