non-linear blending first steps

Code:
  - Add a non-linear blending bit and makeNonlinearBlending()
    to SkColorSpace
  - remove enough F16=linear checks to make it possible to
    create surfaces and encode pngs with nonlinear F16

Testing:
  - add "esrgb" software config to DM, run it
  - add "srgbnl" software config, run it
  - deemphasize importance of "srgb" config on bots
  - update unit tests to reflect relaxed F16 constraints
  - add a new unit test file with _really_ basic tests,
    and a new unit test that's not working yet

Bug: skia:7942

Change-Id: I8ac042bdf9f3d791765393b68fd9256375184d83
Reviewed-on: https://skia-review.googlesource.com/127325
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/src/core/SkColorSpace_XYZ.cpp b/src/core/SkColorSpace_XYZ.cpp
index 17462a117a..968f01d793 100644
--- a/src/core/SkColorSpace_XYZ.cpp
+++ b/src/core/SkColorSpace_XYZ.cpp
@@ -119,3 +119,13 @@ void SkColorSpace_XYZ::toDstGammaTables(const uint8_t* tables[3], sk_sp<SkData>*
     tables[1] = fToDstGammaTables[1];
     tables[2] = fToDstGammaTables[2];
 }
+
+sk_sp<SkColorSpace> SkColorSpace_XYZ::makeNonlinearBlending() const {
+    if (this->nonlinearBlending()) {
+        return sk_ref_sp(const_cast<SkColorSpace_XYZ*>(this));
+    }
+
+    auto cs = sk_make_sp<SkColorSpace_XYZ>(fGammaNamed, fGammas, fToXYZD50, fProfileData);
+    cs->fNonlinearBlending = true;
+    return cs;
+}