Differentiate between sRGBGamma and 2Dot2Gamma

include/core/SkColorSpace.h

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkColorSpace_DEFINED
 #define SkColorSpace_DEFINED
 
 #include "SkMatrix44.h"
 #include "SkRefCnt.h"
 
 class SkColorSpace : public SkRefCnt {
 public:
 
     /**
      *  Common, named profiles that we can recognize.
      */
     enum Named {
         kUnknown_Named,
         kSRGB_Named,
         kAdobeRGB_Named,
     };
 
-    /**
-     *  Create an SkColorSpace from the src gamma and a transform from src gamut to D50 XYZ.
-     */
-    static sk_sp<SkColorSpace> NewRGB(const float gammas[3], const SkMatrix44& toXYZD50);
-
-    /**
-     *  Create a common, named SkColorSpace.
-     */
-    static sk_sp<SkColorSpace> NewNamed(Named);
-
-    /**
-     *  Create an SkColorSpace from an ICC profile.
-     */
-    static sk_sp<SkColorSpace> NewICC(const void*, size_t);
-
     enum GammaNamed {
         kLinear_GammaNamed,
 
         /**
-         *  Gamma curve is a close match to the 2.2f exponential curve.  This is by far
-         *  the most common gamma, and is used by sRGB and Adobe RGB profiles.
+         *  Gamma curve is a close match to the canonical sRGB curve, which has
+         *  a short linear segment followed by a 2.4f exponential.
+         */
+        kSRGB_GammaNamed,
+
+        /**
+         *  Gamma curve is a close match to the 2.2f exponential curve.  This is
+         *  used by Adobe RGB profiles and is common on monitors as well.
          */
         k2Dot2Curve_GammaNamed,
 
         /**
          *  Gamma is represented by a look-up table, a parametric curve, or an uncommon
          *  exponential curve.  Or there is an additional pre-processing step before the
          *  applying the gamma.
          */
         kNonStandard_GammaNamed,
     };
 
+    /**
+     *  Create an SkColorSpace from the src gamma and a transform from src gamut to D50 XYZ.
+     */
+    static sk_sp<SkColorSpace> NewRGB(GammaNamed gammaNamed, const SkMatrix44& toXYZD50);

[msarett, 2016/06/14 21:30:28]

I've changed this to take a GammaNamed instead of float[3].  Trying to write
accurate, fast code for pow has made me think that we really don't want clients
to specify arbitrary floats.

I put the original constructor in SkColorSpace_Base, since it's useful for PNG.

+
+    /**
+     *  Create a common, named SkColorSpace.
+     */
+    static sk_sp<SkColorSpace> NewNamed(Named);
+
+    /**
+     *  Create an SkColorSpace from an ICC profile.
+     */
+    static sk_sp<SkColorSpace> NewICC(const void*, size_t);
+
     GammaNamed gammaNamed() const { return fGammaNamed; }
 
     /**
      *  Returns the matrix used to transform src gamut to XYZ D50.
      */
     const SkMatrix44& xyz() const { return fToXYZD50; }
 
 protected:
 
     SkColorSpace(GammaNamed gammaNamed, const SkMatrix44& toXYZD50, Named named);
 
     const GammaNamed fGammaNamed;
     const SkMatrix44 fToXYZD50;
     const Named      fNamed;
 };
 
 #endif