More shader preliminaries / refactoring

    - thread through ctm
    - make blitter handle paint modulation instead of each shader

TBR=herb@google.com

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4830
CQ_INCLUDE_TRYBOTS=master.client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD-Trybot

Change-Id: I8161e6b3864c4e48e4d47d5ad40a56a13c02fee8
Reviewed-on: https://skia-review.googlesource.com/4830
Reviewed-by: Mike Klein <mtklein@chromium.org>
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>

1 files changed, 7 insertions, 20 deletions

diff --git a/src/core/SkColorShader.cpp b/src/core/SkColorShader.cpp
index 69d9e46b27..072e2a9a5f 100644
--- a/src/core/SkColorShader.cpp
+++ b/src/core/SkColorShader.cpp
@@ -309,34 +309,21 @@ bool SkColor4Shader::Color4Context::onChooseBlitProcs(const SkImageInfo& info, B
     return choose_blitprocs(&fPM4f, info, state);
 }
 
-// To shade a constant color:
-//    1) move the paint color to dst registers
-//    2) load the constant color into the src registers
-//    3) srcin, s' = s*da, modulating the src color by the paint alpha.
-
 bool SkColorShader::onAppendStages(SkRasterPipeline* p,
                                    SkColorSpace* dst,
-                                   SkFallbackAlloc* scratch) const {
+                                   SkFallbackAlloc* scratch,
+                                   const SkMatrix& ctm) const {
     auto color = scratch->make<SkPM4f>(SkPM4f_from_SkColor(fColor, dst));
-    p->append(SkRasterPipeline::move_src_dst);
     p->append(SkRasterPipeline::constant_color, color);
-    if (!append_gamut_transform(p, scratch,
-                                SkColorSpace::MakeNamed(SkColorSpace::kSRGB_Named).get(), dst)) {
-        return false;
-    }
-    p->append(SkRasterPipeline::srcin);
-    return true;
+    return append_gamut_transform(p, scratch,
+                                  SkColorSpace::MakeNamed(SkColorSpace::kSRGB_Named).get(), dst);
 }
 
 bool SkColor4Shader::onAppendStages(SkRasterPipeline* p,
                                     SkColorSpace* dst,
-                                    SkFallbackAlloc* scratch) const {
+                                    SkFallbackAlloc* scratch,
+                                    const SkMatrix& ctm) const {
     auto color = scratch->make<SkPM4f>(fColor4.premul());
-    p->append(SkRasterPipeline::move_src_dst);
     p->append(SkRasterPipeline::constant_color, color);
-    if (!append_gamut_transform(p, scratch, fColorSpace.get(), dst)) {
-        return false;
-    }
-    p->append(SkRasterPipeline::srcin);
-    return true;
+    return append_gamut_transform(p, scratch, fColorSpace.get(), dst);
 }