Reland "Add SkColorSpace factory from 3x3 row-major gamut and transfer function"

Moved named common transfer functions and gamuts to constexpr values in
SkColorSpace.h, in SkNamedTransferFn and SkNamedGamut namespaces.

Converted nearly all SkColorSpace::MakeRGB calls within Skia to use the
new factory with the named values. Multiple clients want a way to
extract named transfer function and gamut - this still doesn't provide
that, but this may be a better path forward for honestly advertising how
SkColorSpace works internally.

Originally landed as:
https://skia.googlesource.com/skia/+/a9549ab31630fc244094e6f1692371cbaf87f666

Re-landing with a new serialization format, but maintaining ability to
load old serialized color spaces, for SKP compatibility.

Bug: skia:
Change-Id: Ib84a6e1cd5d7d9816175773fdbaff2ca32658667
Reviewed-on: https://skia-review.googlesource.com/c/181176
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>

3 files changed, 7 insertions, 10 deletions

diff --git a/tools/flags/SkCommonFlagsConfig.cpp b/tools/flags/SkCommonFlagsConfig.cpp
index 66a5b2a7ba..44e79ac513 100644
--- a/tools/flags/SkCommonFlagsConfig.cpp
+++ b/tools/flags/SkCommonFlagsConfig.cpp
@@ -309,16 +309,13 @@ static bool parse_option_gpu_color(const SkString& value,
         *outColorSpace = SkColorSpace::MakeSRGB();
     } else if (value.equals("p3")) {
         *outColorType = kRGBA_8888_SkColorType;
-        *outColorSpace = SkColorSpace::MakeRGB(SkColorSpace::kSRGB_RenderTargetGamma,
-                                               SkColorSpace::kDCIP3_D65_Gamut);
+        *outColorSpace = SkColorSpace::MakeRGB(SkNamedTransferFn::kSRGB, SkNamedGamut::kDCIP3);
     } else if (value.equals("esrgb")) {
         *outColorType = kRGBA_F16_SkColorType;
         *outColorSpace = SkColorSpace::MakeSRGB();
     } else if (value.equals("narrow") || value.equals("enarrow")) {
-        SkMatrix44 narrow_gamut;
-        narrow_gamut.set3x3RowMajorf(gNarrow_toXYZD50);
         *outColorType = value.equals("narrow") ? kRGBA_8888_SkColorType : kRGBA_F16_SkColorType;
-        *outColorSpace = SkColorSpace::MakeRGB(k2Dot2Curve_SkGammaNamed, narrow_gamut);
+        *outColorSpace = SkColorSpace::MakeRGB(SkNamedTransferFn::k2Dot2, gNarrow_toXYZD50);
     } else if (value.equals("f16")) {
         *outColorType = kRGBA_F16_SkColorType;
         *outColorSpace = SkColorSpace::MakeSRGBLinear();
diff --git a/tools/viewer/Viewer.cpp b/tools/viewer/Viewer.cpp
index fcae406db7..7ec001bac0 100644
--- a/tools/viewer/Viewer.cpp
+++ b/tools/viewer/Viewer.cpp
@@ -185,7 +185,7 @@ Viewer::Viewer(int argc, char** argv, void* platformData)
     , fColorMode(ColorMode::kLegacy)
     , fColorSpacePrimaries(gSrgbPrimaries)
     // Our UI can only tweak gamma (currently), so start out gamma-only
-    , fColorSpaceTransferFn(g2Dot2_TransferFn)
+    , fColorSpaceTransferFn(SkNamedTransferFn::k2Dot2)
     , fZoomLevel(0.0f)
     , fRotation(0.0f)
     , fOffset{0.5f, 0.5f}
@@ -748,7 +748,7 @@ void Viewer::updateTitle() {
         }
         title.appendf(" %s Gamma %f",
                       curPrimaries >= 0 ? gNamedPrimaries[curPrimaries].fName : "Custom",
-                      fColorSpaceTransferFn.fG);
+                      fColorSpaceTransferFn.g);
     }
 
     const DisplayParams& params = fWindow->getRequestedDisplayParams();
@@ -1091,7 +1091,7 @@ void Viewer::drawSlide(SkCanvas* canvas) {
     // If we're in any of the color managed modes, construct the color space we're going to use
     sk_sp<SkColorSpace> colorSpace = nullptr;
     if (ColorMode::kLegacy != fColorMode) {
-        SkMatrix44 toXYZ;
+        skcms_Matrix3x3 toXYZ;
         SkAssertResult(fColorSpacePrimaries.toXYZD50(&toXYZ));
         colorSpace = SkColorSpace::MakeRGB(fColorSpaceTransferFn, toXYZ);
     }
@@ -1835,7 +1835,7 @@ void Viewer::drawImGui() {
                 }
 
                 // Let user adjust the gamma
-                ImGui::SliderFloat("Gamma", &fColorSpaceTransferFn.fG, 0.5f, 3.5f);
+                ImGui::SliderFloat("Gamma", &fColorSpaceTransferFn.g, 0.5f, 3.5f);
 
                 if (ImGui::Combo("Primaries", &primariesIdx,
                                  "sRGB\0AdobeRGB\0P3\0Rec. 2020\0Custom\0\0")) {
diff --git a/tools/viewer/Viewer.h b/tools/viewer/Viewer.h
index e140eb4537..2cff48676c 100644
--- a/tools/viewer/Viewer.h
+++ b/tools/viewer/Viewer.h
@@ -138,7 +138,7 @@ private:
     // Color properties for slide rendering
     ColorMode              fColorMode;
     SkColorSpacePrimaries  fColorSpacePrimaries;
-    SkColorSpaceTransferFn fColorSpaceTransferFn;
+    skcms_TransferFunction fColorSpaceTransferFn;
 
     // transform data
     SkScalar               fZoomLevel;