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, 139 insertions, 0 deletions

diff --git a/src/core/SkColorSpace_Base.h b/src/core/SkColorSpace_Base.h
new file mode 100644
index 0000000000..dbfe7338cd
--- /dev/null
+++ b/src/core/SkColorSpace_Base.h
@@ -0,0 +1,139 @@
+/*
+ * 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_Base_DEFINED
+#define SkColorSpace_Base_DEFINED
+
+#include "SkColorSpace.h"
+
+struct SkGammaCurve {
+    bool isValue() const {
+        bool result = (0.0f != fValue);
+        SkASSERT(!result || (0 == fTableSize));
+        SkASSERT(!result || (0.0f == fG));
+        return result;
+    }
+
+    bool isTable() const {
+        bool result = (0 != fTableSize);
+        SkASSERT(!result || (0.0f == fValue));
+        SkASSERT(!result || (0.0f == fG));
+        SkASSERT(!result || fTable);
+        return result;
+    }
+
+    bool isParametric() const {
+        bool result = (0.0f != fG);
+        SkASSERT(!result || (0.0f == fValue));
+        SkASSERT(!result || (0 == fTableSize));
+        return result;
+    }
+
+    // We have three different ways to represent gamma.
+    // (1) A single value:
+    float                    fValue;
+
+    // (2) A lookup table:
+    uint32_t                 fTableSize;
+    std::unique_ptr<float[]> fTable;
+
+    // (3) Parameters for a curve:
+    //     Y = (aX + b)^g + c  for X >= d
+    //     Y = eX + f          otherwise
+    float                    fG;
+    float                    fA;
+    float                    fB;
+    float                    fC;
+    float                    fD;
+    float                    fE;
+    float                    fF;
+
+    SkGammaCurve() {
+        memset(this, 0, sizeof(struct SkGammaCurve));
+    }
+
+    SkGammaCurve(float value)
+        : fValue(value)
+        , fTableSize(0)
+        , fTable(nullptr)
+        , fG(0.0f)
+        , fA(0.0f)
+        , fB(0.0f)
+        , fC(0.0f)
+        , fD(0.0f)
+        , fE(0.0f)
+        , fF(0.0f)
+    {}
+};
+
+struct SkGammas : public SkRefCnt {
+public:
+    bool isValues() const {
+        return fRed.isValue() && fGreen.isValue() && fBlue.isValue();
+    }
+
+    const SkGammaCurve fRed;
+    const SkGammaCurve fGreen;
+    const SkGammaCurve fBlue;
+
+    SkGammas(float red, float green, float blue)
+        : fRed(red)
+        , fGreen(green)
+        , fBlue(blue)
+    {}
+
+    SkGammas(SkGammaCurve red, SkGammaCurve green, SkGammaCurve blue)
+        : fRed(std::move(red))
+        , fGreen(std::move(green))
+        , fBlue(std::move(blue))
+    {}
+
+    SkGammas() {}
+
+    friend class SkColorSpace;
+};
+
+struct SkColorLookUpTable {
+    static const uint8_t kMaxChannels = 16;
+
+    uint8_t                  fInputChannels;
+    uint8_t                  fOutputChannels;
+    uint8_t                  fGridPoints[kMaxChannels];
+    std::unique_ptr<float[]> fTable;
+
+    SkColorLookUpTable() {
+        memset(this, 0, sizeof(struct SkColorLookUpTable));
+    }
+};
+
+class SkColorSpace_Base : public SkColorSpace {
+public:
+
+    SkGammas* gammas() const { return fGammas.get(); }
+
+private:
+
+    SkColorSpace_Base(sk_sp<SkGammas> gammas, const SkMatrix44& toXYZ, Named);
+
+    SkColorSpace_Base(sk_sp<SkGammas> gammas, GammaNamed gammaNamed, const SkMatrix44& toXYZ,
+                      Named);
+
+    SkColorSpace_Base(SkColorLookUpTable* colorLUT, sk_sp<SkGammas> gammas,
+                      const SkMatrix44& toXYZ);
+
+    SkAutoTDelete<SkColorLookUpTable> fColorLUT;
+    sk_sp<SkGammas>                   fGammas;
+
+    friend class SkColorSpace;
+    typedef SkColorSpace INHERITED;
+};
+
+static inline SkColorSpace_Base* as_CSB(SkColorSpace* colorSpace) {
+    return static_cast<SkColorSpace_Base*>(colorSpace);
+}
+
+#endif