Some simple pipeline refactoring.

This is a batch of little tweaks that all preserve the existing logical behavior:
  - rename dst to move_dst_src to parallel move_src_dst
  - remove unused swap_src_dst
  - move swap_rb up with the other utility stages
  - factor out from_8888() to parallel from_565() and from_4444()
  - factor out gather() from the accum_* stages

This changes the order of the math in accum_8888[_srgb] ever so slightly, from (scale * C) * (1/255.0f) to scale * (1/255.0f * C).  It causes a few pixel diffs, but nothing noticeable.  This makes the 8888 bilerp logic consistent with the other formats, which all convert to [0,1] float first before being scaled.

CQ_INCLUDE_TRYBOTS=skia.primary:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD

Change-Id: Id37857b91be3086565169dcc9b1a537574e532aa
Reviewed-on: https://skia-review.googlesource.com/5226
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Mike Klein <mtklein@chromium.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/core/SkXfermode.cpp b/src/core/SkXfermode.cpp
index eb27f69d26..9c1ae4495d 100644
--- a/src/core/SkXfermode.cpp
+++ b/src/core/SkXfermode.cpp
@@ -1489,7 +1489,7 @@ bool SkBlendMode_AppendStages(SkBlendMode mode, SkRasterPipeline* p) {
     switch (mode) {
         case SkBlendMode::kClear:    stage = SkRasterPipeline::clear; break;
         case SkBlendMode::kSrc:      return true;  // This stage is a no-op.
-        case SkBlendMode::kDst:      stage = SkRasterPipeline::dst; break;
+        case SkBlendMode::kDst:      stage = SkRasterPipeline::move_dst_src; break;
         case SkBlendMode::kSrcOver:  stage = SkRasterPipeline::srcover; break;
         case SkBlendMode::kDstOver:  stage = SkRasterPipeline::dstover; break;
         case SkBlendMode::kSrcIn:    stage = SkRasterPipeline::srcin; break;