SkValue: SkXfermode

src/effects/SkToFromValue.cpp

Index: src/effects/SkToFromValue.cpp
diff --git a/src/effects/SkToFromValue.cpp b/src/effects/SkToFromValue.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..b981d1715ee4d475f9b90363cdb10a301e0e74cb
--- /dev/null
+++ b/src/effects/SkToFromValue.cpp
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+/*
+ * 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 "SkArithmeticMode.h"
+#include "SkLerpXfermode.h"
+#include "SkMatrix.h"
+#include "SkPixelXorXfermode.h"
+#include "SkToFromValue.h"
+#include "SkValueKeys.h"
+#include "SkXfermode.h"
+
+////////////////////////////////////////////////////////////////////////////////
+
+#define REQUIRE(cond) do { if (!(cond)) { SkASSERT(false); return false; } } while (false)
+
+template <typename T>
+bool getT(const SkValue& obj, SkValue::Key key, T* ptr) {
+    auto v = obj.get(key);
+    return v ? SkFromValue(*v, ptr) : false;
+}
+
+template<> bool SkFromValue<float>(const SkValue& val, float* f) {
+    REQUIRE(val.type() == SkValue::F32);
+    *f = val.f32();
+    return true;
+}
+
+template<> bool SkFromValue<int32_t>(const SkValue& val, int32_t* x) {
+    REQUIRE(val.type() == SkValue::S32);
+    *x = val.s32();
+    return true;
+}
+
+template<> bool SkFromValue<uint32_t>(const SkValue& val, uint32_t* x) {
+    REQUIRE(val.type() == SkValue::U32);
+    *x = val.u32();
+    return true;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+template<> SkValue SkToValue<SkMatrix>(const SkMatrix& mat) {
+    auto val = SkValue::Object(SkValue::Matrix);
+    for (int i = 0; i < 9; ++i) {
+        if (mat[i] != SkMatrix::I()[i]) {
+            val.set(i, SkValue::FromF32(mat[i]));
+        }
+    }
+    return val;
+}
+
+template<> bool SkFromValue<SkMatrix>(const SkValue& val, SkMatrix* m) {
+    REQUIRE(val.type() == SkValue::Matrix);
+    *m = SkMatrix::I();
+    for (int i = 0; i < 9; i++) {
+        getT(val, i, &(*m)[i]);
+    }
+    return true;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+template<> SkValue SkToValue<SkXfermode>(const SkXfermode* x) {
+    return x ? x->asValue() : SkValue::Object(SkValue::DefaultXfermode);
+}
+
+static bool from_value_DefaultXfermode(const SkValue& val,
+                                       SkAutoTUnref<SkXfermode>* dst) {
+    dst->reset(nullptr);
+    return true;
+}
+
+static bool from_value_ArithmeticXfermode(const SkValue& val,
+                                          SkAutoTUnref<SkXfermode>* dst) {
+    using namespace SkValueKeys::ArithmeticXfermode;
+    float k[4];
+    REQUIRE(getT(val, kK0, &k[0]));
+    REQUIRE(getT(val, kK1, &k[1]));
+    REQUIRE(getT(val, kK2, &k[2]));
+    REQUIRE(getT(val, kK3, &k[3]));
+    int32_t enforce = true;
+    getT(val, kEnforcePMColor, &enforce);
+    dst->reset(SkArithmeticMode::Create(
+                       k[0], k[1], k[2], k[3], SkToBool(enforce)));
+    return true;
+}
+
+static bool from_value_LerpXfermode(const SkValue& val,
+                                    SkAutoTUnref<SkXfermode>* dst) {
+    float scale;
+    REQUIRE(getT(val, SkValueKeys::LerpXfermode::kScale, &scale));
+    dst->reset(SkLerpXfermode::Create(scale));
+    return true;
+}
+
+static bool from_value_PixelXorXfermode(const SkValue& val,
+                                        SkAutoTUnref<SkXfermode>* dst) {
+    uint32_t opColor;
+    REQUIRE(getT(val, SkValueKeys::PixelXorXfermode::kOpColor, &opColor));
+    dst->reset(SkPixelXorXfermode::Create(opColor));
+    return true;
+}
+
+static bool from_value_ProcCoeffXfermode(const SkValue& val,
+                                         SkAutoTUnref<SkXfermode>* dst) {
+    uint32_t mode;
+    REQUIRE(getT(val, SkValueKeys::ProcCoeffXfermode::kMode, &mode));
+    dst->reset(SkXfermode::Create((SkXfermode::Mode)mode));
+    return true;
+}
+
+template<> bool SkFromValue< SkAutoTUnref<SkXfermode> >(
+        const SkValue& val, SkAutoTUnref<SkXfermode>* dst) {
+    switch (val.type()) {
+        case SkValue::DefaultXfermode:    return from_value_DefaultXfermode(val, dst);
+        case SkValue::ArithmeticXfermode: return from_value_ArithmeticXfermode(val, dst);
+        case SkValue::LerpXfermode:       return from_value_LerpXfermode(val, dst);
+        case SkValue::PixelXorXfermode:   return from_value_PixelXorXfermode(val, dst);
+        case SkValue::ProcCoeffXfermode:  return from_value_ProcCoeffXfermode(val, dst);
+        default:                          REQUIRE(false);
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+#undef REQUIRE
+