Make SkColorSpace a public API

I've trimmed uniqueID for now, and added some comments.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1996973002

Review-Url: https://codereview.chromium.org/1996973002

1 files changed, 75 insertions, 0 deletions

diff --git a/include/core/SkColorSpace.h b/include/core/SkColorSpace.h
new file mode 100644
index 0000000000..9630fe4c25
--- /dev/null
+++ b/include/core/SkColorSpace.h
@@ -0,0 +1,75 @@
+/*
+ * 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"
+#include "../private/SkTemplates.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(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.
+         */
+        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,
+    };
+
+    GammaNamed gammaNamed() const { return fGammaNamed; }
+
+    /**
+     *  Returns the matrix used to transform src gamut to XYZ D50.
+     */
+    SkMatrix44 xyz() const { return fToXYZD50; }
+
+protected:
+
+    SkColorSpace(GammaNamed gammaNamed, const SkMatrix44& toXYZD50, Named named);
+
+    const GammaNamed                  fGammaNamed;
+    const SkMatrix44                  fToXYZD50;
+    const Named                       fNamed;
+};
+
+#endif