Refactored SkColorSpace and added in a Lab PCS GM

src/core/SkColorSpace_XYZ.cpp

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkColorSpace_XYZ.h"
+#include "SkColorSpaceXform_Base.h"
+
+static constexpr float gSRGB_toXYZD50[] {
+    0.4358f, 0.3853f, 0.1430f,    // Rx, Gx, Bx
+    0.2224f, 0.7170f, 0.0606f,    // Ry, Gy, Gz
+    0.0139f, 0.0971f, 0.7139f,    // Rz, Gz, Bz
+};
+
+SkColorSpace_XYZ::SkColorSpace_XYZ(SkGammaNamed gammaNamed, const SkMatrix44& toXYZD50)
+    : INHERITED(nullptr)
+    , fGammaNamed(gammaNamed)
+    , fGammas(nullptr)
+    , fToXYZD50(toXYZD50)
+    , fFromXYZD50(SkMatrix44::kUninitialized_Constructor)
+{}
+
+SkColorSpace_XYZ::SkColorSpace_XYZ(SkGammaNamed gammaNamed, sk_sp<SkGammas> gammas,
+                                   const SkMatrix44& toXYZD50, sk_sp<SkData> profileData)
+    : INHERITED(std::move(profileData))
+    , fGammaNamed(gammaNamed)
+    , fGammas(std::move(gammas))
+    , fToXYZD50(toXYZD50)
+    , fFromXYZD50(SkMatrix44::kUninitialized_Constructor)
+{}
+
+const SkMatrix44* SkColorSpace_XYZ::fromXYZD50() const {
+    fFromXYZOnce([this] {
+        if (!fToXYZD50.invert(&fFromXYZD50)) {
+            // If a client gives us a dst gamut with a transform that we can't invert, we will
+            // simply give them back a transform to sRGB gamut.
+            SkDEBUGFAIL("Non-invertible XYZ matrix, defaulting to sRGB");
+            SkMatrix44 srgbToxyzD50(SkMatrix44::kUninitialized_Constructor);
+            srgbToxyzD50.set3x3RowMajorf(gSRGB_toXYZD50);
+            srgbToxyzD50.invert(&fFromXYZD50);
+        }
+    });
+    return &fFromXYZD50;
+}
+
+bool SkColorSpace_XYZ::onGammaCloseToSRGB() const {
+    return kSRGB_SkGammaNamed == fGammaNamed || k2Dot2Curve_SkGammaNamed == fGammaNamed;
+}
+
+bool SkColorSpace_XYZ::onGammaIsLinear() const {
+    return kLinear_SkGammaNamed == fGammaNamed;
+}
+
+sk_sp<SkColorSpace> SkColorSpace_XYZ::makeLinearGamma() {
+    if (this->gammaIsLinear()) {
+        return sk_ref_sp(this);
+    }
+    return SkColorSpace_Base::NewRGB(kLinear_SkGammaNamed, fToXYZD50);
+}
+
+void SkColorSpace_XYZ::toDstGammaTables(const uint8_t* tables[3], sk_sp<SkData>* storage,
+                                         int numTables) const {
+    fToDstGammaOnce([this, numTables] {
+        const bool gammasAreMatching = numTables <= 1;
+        fDstStorage =
+                SkData::MakeUninitialized(numTables * SkColorSpaceXform_Base::kDstGammaTableSize);
+        SkColorSpaceXform_Base::BuildDstGammaTables(fToDstGammaTables,
+                                                    (uint8_t*) fDstStorage->writable_data(), this,
+                                                    gammasAreMatching);
+    });
+
+    *storage = fDstStorage;
+    tables[0] = fToDstGammaTables[0];
+    tables[1] = fToDstGammaTables[1];
+    tables[2] = fToDstGammaTables[2];
+}