Add initial implementation of GrShape and GrStyle classes and tests

tests/GrShapeTest.cpp

Index: tests/GrShapeTest.cpp
diff --git a/tests/GrShapeTest.cpp b/tests/GrShapeTest.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..62440d4ba528c7458e326d4f4158fb6a80c278cd
--- /dev/null
+++ b/tests/GrShapeTest.cpp
@@ -0,0 +1,316 @@
+/*
+ * 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 <initializer_list>
+#include <functional>
+#include "Test.h"
+#if SK_SUPPORT_GPU
+#include "GrShape.h"
+#include "SkPath.h"
+#include "SkDashPathEffect.h"
+
+namespace {
+class TestCase {
+public:
+    TestCase(const SkRRect& rrect, const SkPaint& paint) : fBase(rrect, paint) {
+        this->init();
+    }
+
+    struct SelfExpectations {
+        bool fPEHasEffect;
+        bool fPEHasValidKey;
+        bool fStrokeApplies;
+    };
+
+    void testExpectations(skiatest::Reporter* reporter, SelfExpectations expectations) const;
+
+    enum ComparisonExpecation {
+        kAllDifferent_ComparisonExpecation,
+        kSameUpToPE_ComparisonExpecation,
+        kSameUpToStroke_ComparisonExpecation,
+        kAllSame_ComparisonExpecation,
+    };
+
+    void compare(skiatest::Reporter*, const TestCase& that, ComparisonExpecation) const;
+
+private:
+    void init() {
+        fAppliedPE           = fBase.applyPathEffect();
+        fAppliedPEThenStroke = fAppliedPE.applyFullStyle();
+        fAppliedFull         = fBase.applyFullStyle();
+
+        fBaseKeyIsValid                = MakeKey(&fBaseKey, fBase);
+        fAppliedPEKeyIsValid           = MakeKey(&fAppliedPEKey, fAppliedPE);
+        fAppliedPEThenStrokeKeyIsValid = MakeKey(&fAppliedPEThenStrokeKey, fAppliedPEThenStroke);
+        fAppliedFullKeyIsValid         = MakeKey(&fAppliedFullKey, fAppliedFull);
+    }
+
+    using Key = SkTArray<uint32_t>;
+
+    static bool MakeKey(Key* key, const GrShape& shape) {
+        int size = shape.unstyledKeySize();
+        if (size <= 0) {
+            return false;
+        }
+        key->reset(size);
+        shape.writeUnstyledKey(key->begin());
+        return true;
+    }
+
+    GrShape fBase;
+    GrShape fAppliedPE;
+    GrShape fAppliedPEThenStroke;
+    GrShape fAppliedFull;
+
+    Key fBaseKey;
+    Key fAppliedPEKey;
+    Key fAppliedPEThenStrokeKey;
+    Key fAppliedFullKey;
+
+    bool fBaseKeyIsValid;
+    bool fAppliedPEKeyIsValid;
+    bool fAppliedPEThenStrokeKeyIsValid;
+    bool fAppliedFullKeyIsValid;
+};
+
+void TestCase::testExpectations(skiatest::Reporter* reporter, SelfExpectations expectations) const {
+    // Applying the path effect and then the stroke should always be the same as applying
+    // both in one go.
+    REPORTER_ASSERT(reporter, fAppliedPEThenStrokeKey == fAppliedFullKey);
+    // The base's key should always be valid (unless the path is volatile)
+    REPORTER_ASSERT(reporter, fBaseKeyIsValid);
+    if (expectations.fPEHasEffect) {
+        REPORTER_ASSERT(reporter, fBaseKey != fAppliedPEKey);
+        REPORTER_ASSERT(reporter, expectations.fPEHasEffect == fAppliedPEKeyIsValid);
+        REPORTER_ASSERT(reporter, fBaseKey != fAppliedFullKey);
+        REPORTER_ASSERT(reporter, expectations.fPEHasEffect == fAppliedFullKeyIsValid);
+        if (expectations.fStrokeApplies && expectations.fPEHasValidKey) {
+            REPORTER_ASSERT(reporter, fAppliedPEKey != fAppliedFullKey);
+            REPORTER_ASSERT(reporter, expectations.fPEHasEffect == fAppliedFullKeyIsValid);
+        }
+    } else {
+        REPORTER_ASSERT(reporter, fBaseKey == fAppliedPEKey);
+        if (expectations.fStrokeApplies) {
+            REPORTER_ASSERT(reporter, fBaseKey != fAppliedFullKey);
+        } else {
+            REPORTER_ASSERT(reporter, fBaseKey == fAppliedFullKey);
+        }
+    }
+}
+
+void TestCase::compare(skiatest::Reporter* reporter, const TestCase& that,
+                       ComparisonExpecation expectation) const {
+    switch (expectation) {
+        case kAllDifferent_ComparisonExpecation:
+            REPORTER_ASSERT(reporter, fBaseKey != that.fBaseKey);
+            REPORTER_ASSERT(reporter, fAppliedPEKey != that.fAppliedPEKey);
+            REPORTER_ASSERT(reporter, fAppliedFullKey != that.fAppliedFullKey);
+            break;
+        case kSameUpToPE_ComparisonExpecation:
+            REPORTER_ASSERT(reporter, fBaseKey == that.fBaseKey);
+            REPORTER_ASSERT(reporter, fAppliedPEKey != that.fAppliedPEKey);
+            REPORTER_ASSERT(reporter, fAppliedFullKey != that.fAppliedFullKey);
+            break;
+        case kSameUpToStroke_ComparisonExpecation:
+            REPORTER_ASSERT(reporter, fBaseKey == that.fBaseKey);
+            REPORTER_ASSERT(reporter, fAppliedPEKey == that.fAppliedPEKey);
+            REPORTER_ASSERT(reporter, fAppliedFullKey != that.fAppliedFullKey);
+            break;
+        case kAllSame_ComparisonExpecation:
+            REPORTER_ASSERT(reporter, fBaseKey == that.fBaseKey);
+            REPORTER_ASSERT(reporter, fAppliedPEKey == that.fAppliedPEKey);
+            REPORTER_ASSERT(reporter, fAppliedFullKey == that.fAppliedFullKey);
+            break;
+    }
+}
+}  // namespace
+
+static sk_sp<SkPathEffect> make_dash() {
+    static const SkScalar kIntervals[] = { 0.25, 3.f, 0.5, 2.f };
+    static const SkScalar kPhase = 0.75;
+    return SkDashPathEffect::Make(kIntervals, SK_ARRAY_COUNT(kIntervals), kPhase);
+}
+
+static sk_sp<SkPathEffect> make_null_dash() {
+    static const SkScalar kNullIntervals[] = {0, 0, 0, 0, 0, 0};
+    return SkDashPathEffect::Make(kNullIntervals, SK_ARRAY_COUNT(kNullIntervals), 0.f);
+}
+
+static void test_basic(skiatest::Reporter* reporter, const SkRRect& rrect) {
+    sk_sp<SkPathEffect> dashPE = make_dash();
+
+    TestCase::SelfExpectations expectations;
+    SkPaint fill;
+
+    TestCase fillCase(rrect, fill);
+    expectations.fPEHasEffect = false;
+    expectations.fPEHasValidKey = false;
+    expectations.fStrokeApplies = false;
+    fillCase.testExpectations(reporter, expectations);
+    // Test that another GrShape instance built from the same primitive is the same.
+    TestCase(rrect, fill).compare(reporter, fillCase, TestCase::kAllSame_ComparisonExpecation);
+
+    SkPaint stroke2RoundBevel;
+    stroke2RoundBevel.setStyle(SkPaint::kStroke_Style);
+    stroke2RoundBevel.setStrokeCap(SkPaint::kRound_Cap);
+    stroke2RoundBevel.setStrokeJoin(SkPaint::kBevel_Join);
+    stroke2RoundBevel.setStrokeWidth(2.f);
+    TestCase stroke2RoundBevelCase(rrect, stroke2RoundBevel);
+    expectations.fPEHasValidKey = true;
+    expectations.fPEHasEffect = false;
+    expectations.fStrokeApplies = true;
+    stroke2RoundBevelCase.testExpectations(reporter, expectations);
+    TestCase(rrect, stroke2RoundBevel).compare(reporter, stroke2RoundBevelCase,
+                                               TestCase::kAllSame_ComparisonExpecation);
+
+    SkPaint stroke2RoundBevelDash = stroke2RoundBevel;
+    stroke2RoundBevelDash.setPathEffect(make_dash());
+    TestCase stroke2RoundBevelDashCase(rrect, stroke2RoundBevelDash);
+    expectations.fPEHasValidKey = true;
+    expectations.fPEHasEffect = true;
+    expectations.fStrokeApplies = true;
+    stroke2RoundBevelDashCase.testExpectations(reporter, expectations);
+    TestCase(rrect, stroke2RoundBevelDash).compare(reporter, stroke2RoundBevelDashCase,
+                                                   TestCase::kAllSame_ComparisonExpecation);
+
+    fillCase.compare(reporter, stroke2RoundBevelCase,
+                     TestCase::kSameUpToStroke_ComparisonExpecation);
+    fillCase.compare(reporter, stroke2RoundBevelDashCase,
+                     TestCase::kSameUpToPE_ComparisonExpecation);
+    stroke2RoundBevelCase.compare(reporter, stroke2RoundBevelDashCase,
+                                  TestCase::kSameUpToPE_ComparisonExpecation);
+}
+
+template <typename T>
+static void test_stroke_param(skiatest::Reporter* reporter, const SkRRect& rrect,
+                              std::function<void(SkPaint*, T)> setter, T a, T b) {
+    // Set the stroke width so that we don't get hairline. However, call the function second so that
+    // it can override.
+    SkPaint strokeA;
+    strokeA.setStyle(SkPaint::kStroke_Style);
+    strokeA.setStrokeWidth(2.f);
+    setter(&strokeA, a);
+    SkPaint strokeB;
+    strokeB.setStyle(SkPaint::kStroke_Style);
+    strokeB.setStrokeWidth(2.f);
+    setter(&strokeB, b);
+
+    TestCase strokeACase(rrect, strokeA);
+    TestCase strokeBCase(rrect, strokeB);
+    strokeACase.compare(reporter, strokeBCase, TestCase::kSameUpToStroke_ComparisonExpecation);
+
+    // Make sure stroking params don't affect fill style.
+    SkPaint fillA = strokeA, fillB = strokeB;
+    fillA.setStyle(SkPaint::kFill_Style);
+    fillB.setStyle(SkPaint::kFill_Style);
+    TestCase fillACase(rrect, fillA);
+    TestCase fillBCase(rrect, fillB);
+    fillACase.compare(reporter, fillBCase, TestCase::kAllSame_ComparisonExpecation);
+
+    // Make sure just applying the dash but not stroke gives the same key for both stroking
+    // variations.
+    SkPaint dashA = strokeA, dashB = strokeB;
+    dashA.setPathEffect(make_dash());
+    dashB.setPathEffect(make_dash());
+    TestCase dashACase(rrect, dashA);
+    TestCase dashBCase(rrect, dashB);
+    dashACase.compare(reporter, dashBCase, TestCase::kSameUpToStroke_ComparisonExpecation);
+}
+
+static void test_miter_limit(skiatest::Reporter* reporter, const SkRRect& rrect) {
+    // Miter limit should only matter when stroking with miter joins. It shouldn't affect other
+    // joins or fills.
+    SkPaint miterA;
+    miterA.setStyle(SkPaint::kStroke_Style);
+    miterA.setStrokeWidth(2.f);
+    miterA.setStrokeJoin(SkPaint::kMiter_Join);
+    miterA.setStrokeMiter(0.5f);
+    SkPaint miterB = miterA;
+    miterA.setStrokeMiter(0.6f);
+
+    TestCase miterACase(rrect, miterA);
+    TestCase miterBCase(rrect, miterB);
+    miterACase.compare(reporter, miterBCase, TestCase::kSameUpToStroke_ComparisonExpecation);
+
+    SkPaint noMiterA = miterA, noMiterB = miterB;
+    noMiterA.setStrokeJoin(SkPaint::kRound_Join);
+    noMiterB.setStrokeJoin(SkPaint::kRound_Join);
+    TestCase noMiterACase(rrect, noMiterA);
+    TestCase noMiterBCase(rrect, noMiterB);
+    noMiterACase.compare(reporter, noMiterBCase, TestCase::kAllSame_ComparisonExpecation);
+
+    SkPaint fillA = miterA, fillB = miterB;
+    fillA.setStyle(SkPaint::kFill_Style);
+    fillB.setStyle(SkPaint::kFill_Style);
+    TestCase fillACase(rrect, fillA);
+    TestCase fillBCase(rrect, fillB);
+    fillACase.compare(reporter, fillBCase, TestCase::kAllSame_ComparisonExpecation);
+}
+
+static void test_dash_fill(skiatest::Reporter* reporter, const SkRRect& rrect) {
+    // A dash with no stroke should have no effect
+    using DashFactoryFn = sk_sp<SkPathEffect>(*)();
+    for (DashFactoryFn md : {&make_dash, &make_null_dash}) {
+        SkPaint dashFill;
+        dashFill.setPathEffect((*md)());
+        TestCase dashFillCase(rrect, dashFill);
+
+        TestCase fillCase(rrect, SkPaint());
+        dashFillCase.compare(reporter, fillCase, TestCase::kAllSame_ComparisonExpecation);
+    }
+}
+
+void test_null_dash(skiatest::Reporter* reporter, const SkRRect& rrect) {
+    SkPaint fill;
+    SkPaint stroke;
+    stroke.setStyle(SkPaint::kStroke_Style);
+    stroke.setStrokeWidth(1.f);
+    SkPaint dash;
+    dash.setStyle(SkPaint::kStroke_Style);
+    dash.setStrokeWidth(1.f);
+    dash.setPathEffect(make_dash());
+    SkPaint nullDash;
+    nullDash.setStyle(SkPaint::kStroke_Style);
+    nullDash.setStrokeWidth(1.f);
+    nullDash.setPathEffect(make_null_dash());
+
+    TestCase fillCase(rrect, fill);
+    TestCase strokeCase(rrect, stroke);
+    TestCase dashCase(rrect, dash);
+    TestCase nullDashCase(rrect, nullDash);
+
+    nullDashCase.compare(reporter, fillCase, TestCase::kSameUpToStroke_ComparisonExpecation);
+    nullDashCase.compare(reporter, strokeCase, TestCase::kAllSame_ComparisonExpecation);
+    nullDashCase.compare(reporter, dashCase, TestCase::kSameUpToPE_ComparisonExpecation);
+}
+
+DEF_TEST(GrShape, reporter) {
+    sk_sp<SkPathEffect> dashPE = make_dash();
+
+    for (auto rr : { SkRRect::MakeRect(SkRect::MakeWH(10, 10)),
+                     SkRRect::MakeRectXY(SkRect::MakeWH(10, 10), 3, 4)}) {
+        test_basic(reporter, rr);
+        test_dash_fill(reporter, rr);
+        test_null_dash(reporter, rr);
+        // Test modifying various stroke params.
+        test_stroke_param<SkScalar>(
+                          reporter, rr,
+                          [](SkPaint* p, SkScalar w) { p->setStrokeWidth(w);},
+                          SkIntToScalar(2), SkIntToScalar(4));
+        test_stroke_param<SkPaint::Cap>(
+                          reporter, rr,
+                          [](SkPaint* p, SkPaint::Cap c) { p->setStrokeCap(c);},
+                          SkPaint::kButt_Cap, SkPaint::kRound_Cap);
+        test_stroke_param<SkPaint::Join>(
+                          reporter, rr,
+                          [](SkPaint* p, SkPaint::Join j) { p->setStrokeJoin(j);},
+                          SkPaint::kMiter_Join, SkPaint::kRound_Join);
+        test_miter_limit(reporter, rr);
+    }
+}
+
+#endif