Gamut transformation of the paint color in Ganesh

Conversion from sRGB to destination gamut is going to be very common,
so I'm caching that xform (if there is one) on the draw context.

Results verified in the gamut GM (two more boxes correct).

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2330553003

Review-Url: https://codereview.chromium.org/2330553003

include/gpu/GrColorSpaceXform.h

@@ -8,6 +8,7 @@
 #ifndef GrColorSpaceXform_DEFINED
 #define GrColorSpaceXform_DEFINED
 
+#include "GrColor.h"
 #include "SkMatrix44.h"
 #include "SkRefCnt.h"
 
@@ -33,6 +34,8 @@ public:
         return SkToBool(xform) ? 1 : 0;
     }
 
+    GrColor4f apply(const GrColor4f& srcColor);
+
 private:
     SkMatrix44 fSrcToDst;
 };

include/gpu/GrDrawContext.h

@@ -335,6 +335,7 @@ public:
     }
     const SkSurfaceProps& surfaceProps() const { return fSurfaceProps; }
     SkColorSpace* getColorSpace() const { return fColorSpace.get(); }
+    GrColorSpaceXform* getColorXformFromSRGB() const { return fColorXformFromSRGB.get(); }
     GrSurfaceOrigin origin() const { return fRenderTarget->origin(); }
 
     bool wasAbandoned() const;
@@ -425,6 +426,7 @@ private:
     GrInstancedPipelineInfo           fInstancedPipelineInfo;
 
     sk_sp<SkColorSpace>               fColorSpace;
+    sk_sp<GrColorSpaceXform>          fColorXformFromSRGB;
     SkSurfaceProps                    fSurfaceProps;
     GrAuditTrail*                     fAuditTrail;
 

src/gpu/GrColorSpaceXform.cpp

@@ -58,3 +58,9 @@ sk_sp<GrColorSpaceXform> GrColorSpaceXform::Make(SkColorSpace* src, SkColorSpace
 
     return sk_make_sp<GrColorSpaceXform>(srcToDst);
 }
+
+GrColor4f GrColorSpaceXform::apply(const GrColor4f& srcColor) {
+    GrColor4f result;
+    fSrcToDst.mapScalars(srcColor.fRGBA, result.fRGBA);
+    return result;
+}

src/gpu/GrDrawContext.cpp

@@ -86,12 +86,18 @@ GrDrawContext::GrDrawContext(GrContext* context,
     , fContext(context)
     , fInstancedPipelineInfo(fRenderTarget.get())
     , fColorSpace(std::move(colorSpace))
+    , fColorXformFromSRGB(nullptr)
     , fSurfaceProps(SkSurfacePropsCopyOrDefault(surfaceProps))
     , fAuditTrail(auditTrail)
 #ifdef SK_DEBUG
     , fSingleOwner(singleOwner)
 #endif
 {
+    if (fColorSpace) {
+        // sRGB sources are very common (SkColor, etc...), so we cache that gamut transformation
+        auto srgbColorSpace = SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named);
+        fColorXformFromSRGB = GrColorSpaceXform::Make(srgbColorSpace.get(), fColorSpace.get());
+    }
     SkDEBUGCODE(this->validate();)
 }
 

src/gpu/SkGr.cpp

@@ -537,6 +537,10 @@ static inline bool skpaint_to_grpaint_impl(GrContext* context,
         origColor.fRGBA[0] = exact_srgb_to_linear(origColor.fRGBA[0]);
         origColor.fRGBA[1] = exact_srgb_to_linear(origColor.fRGBA[1]);
         origColor.fRGBA[2] = exact_srgb_to_linear(origColor.fRGBA[2]);
+
+        if (dc->getColorXformFromSRGB()) {
+            origColor = dc->getColorXformFromSRGB()->apply(origColor);
+        }
     }
 
     // Setup the initial color considering the shader, the SkPaint color, and the presence or not