[Impeller] Add stream ops to Vector3 and Vector4

impeller/geometry/geometry_unittests.cc

@@ -1616,32 +1616,94 @@ TEST(GeometryTest, VerticesConstructorAndGetters) {
 }
 
 TEST(GeometryTest, MatrixPrinting) {
-  std::stringstream stream;
-
-  Matrix m;
-
-  stream << m;
-
-  ASSERT_EQ(stream.str(), R"((
+  {
+    std::stringstream stream;
+    Matrix m;
+    stream << m;
+    ASSERT_EQ(stream.str(), R"((
        1.000000,       0.000000,       0.000000,       0.000000,
        0.000000,       1.000000,       0.000000,       0.000000,
        0.000000,       0.000000,       1.000000,       0.000000,
        0.000000,       0.000000,       0.000000,       1.000000,
 ))");
+  }
 
-  stream.str("");
-  stream.clear();
-
-  m = Matrix::MakeTranslation(Vector3(10, 20, 30));
-
-  stream << m;
+  {
+    std::stringstream stream;
+    Matrix m = Matrix::MakeTranslation(Vector3(10, 20, 30));
+    stream << m;
 
-  ASSERT_EQ(stream.str(), R"((
+    ASSERT_EQ(stream.str(), R"((
        1.000000,       0.000000,       0.000000,      10.000000,
        0.000000,       1.000000,       0.000000,      20.000000,
        0.000000,       0.000000,       1.000000,      30.000000,
        0.000000,       0.000000,       0.000000,       1.000000,
 ))");
+  }
+}
+
+TEST(GeometryTest, PointPrinting) {
+  {
+    std::stringstream stream;
+    Point m;
+    stream << m;
+    ASSERT_EQ(stream.str(), "(0, 0)");
+  }
+
+  {
+    std::stringstream stream;
+    Point m(13, 37);
+    stream << m;
+    ASSERT_EQ(stream.str(), "(13, 37)");
+  }
+}
+
+TEST(GeometryTest, Vector3Printing) {
+  {
+    std::stringstream stream;
+    Vector3 m;
+    stream << m;
+    ASSERT_EQ(stream.str(), "(0, 0, 0)");
+  }
+
+  {
+    std::stringstream stream;
+    Vector3 m(1, 2, 3);
+    stream << m;
+    ASSERT_EQ(stream.str(), "(1, 2, 3)");
+  }
+}
+
+TEST(GeometryTest, Vector4Printing) {
+  {
+    std::stringstream stream;
+    Vector4 m;
+    stream << m;
+    ASSERT_EQ(stream.str(), "(0, 0, 0, 1)");
+  }
+
+  {
+    std::stringstream stream;
+    Vector4 m(1, 2, 3, 4);
+    stream << m;
+    ASSERT_EQ(stream.str(), "(1, 2, 3, 4)");
+  }
+}
+
+TEST(GeometryTest, ColorPrinting) {
+  {
+    std::stringstream stream;
+    Color m;
+    stream << m;
+    ASSERT_EQ(stream.str(), "(0, 0, 0, 0)");
+  }
+
+  {
+    std::stringstream stream;
+    Color m(1, 2, 3, 4);
+    stream << m;
+    ASSERT_EQ(stream.str(), "(1, 2, 3, 4)");
+  }
 }
 
 TEST(GeometryTest, Gradient) {

impeller/geometry/vector.h

@@ -247,3 +247,17 @@ static_assert(sizeof(Vector3) == 3 * sizeof(Scalar));
 static_assert(sizeof(Vector4) == 4 * sizeof(Scalar));
 
 }  // namespace impeller
+
+namespace std {
+
+inline std::ostream& operator<<(std::ostream& out, const impeller::Vector3& p) {
+  out << "(" << p.x << ", " << p.y << ", " << p.z << ")";
+  return out;
+}
+
+inline std::ostream& operator<<(std::ostream& out, const impeller::Vector4& p) {
+  out << "(" << p.x << ", " << p.y << ", " << p.z << ", " << p.w << ")";
+  return out;
+}
+
+}  // namespace std