Add assignment operators to point (flutter#26)

Author: bdero

impeller/geometry/geometry_unittests.cc

@@ -393,6 +393,66 @@ TEST(GeometryTest, SizeCoercesToPoint) {
   }
 }
 
+TEST(GeometryTest, CanUsePointAssignmentOperators) {
+  // Point on RHS
+  {
+    IPoint p(1, 2);
+    p += IPoint(1, 2);
+    ASSERT_EQ(p.x, 2u);
+    ASSERT_EQ(p.y, 4u);
+  }
+
+  {
+    IPoint p(3, 6);
+    p -= IPoint(1, 2);
+    ASSERT_EQ(p.x, 2u);
+    ASSERT_EQ(p.y, 4u);
+  }
+
+  {
+    IPoint p(1, 2);
+    p *= IPoint(2, 3);
+    ASSERT_EQ(p.x, 2u);
+    ASSERT_EQ(p.y, 6u);
+  }
+
+  {
+    IPoint p(2, 6);
+    p /= IPoint(2, 3);
+    ASSERT_EQ(p.x, 1u);
+    ASSERT_EQ(p.y, 2u);
+  }
+
+  // Size on RHS
+  {
+    IPoint p(1, 2);
+    p += ISize(1, 2);
+    ASSERT_EQ(p.x, 2u);
+    ASSERT_EQ(p.y, 4u);
+  }
+
+  {
+    IPoint p(3, 6);
+    p -= ISize(1, 2);
+    ASSERT_EQ(p.x, 2u);
+    ASSERT_EQ(p.y, 4u);
+  }
+
+  {
+    IPoint p(1, 2);
+    p *= ISize(2, 3);
+    ASSERT_EQ(p.x, 2u);
+    ASSERT_EQ(p.y, 6u);
+  }
+
+  {
+    IPoint p(2, 6);
+    p /= ISize(2, 3);
+    ASSERT_EQ(p.x, 1u);
+    ASSERT_EQ(p.y, 2u);
+  }
+}
+
 TEST(GeometryTest, CanConvertBetweenDegressAndRadians) {
   {
     auto deg = Degrees{90.0};

impeller/geometry/point.h

@@ -45,6 +45,62 @@ struct TPoint {
     return p.x != x || p.y != y;
   }
 
+  template <class U>
+  inline TPoint operator+=(const TPoint<U>& p) {
+    x += static_cast<Type>(p.x);
+    y += static_cast<Type>(p.y);
+    return *this;
+  }
+
+  template <class U>
+  inline TPoint operator+=(const TSize<U>& s) {
+    x += static_cast<Type>(s.width);
+    y += static_cast<Type>(s.height);
+    return *this;
+  }
+
+  template <class U>
+  inline TPoint operator-=(const TPoint<U>& p) {
+    x -= static_cast<Type>(p.x);
+    y -= static_cast<Type>(p.y);
+    return *this;
+  }
+
+  template <class U>
+  inline TPoint operator-=(const TSize<U>& s) {
+    x -= static_cast<Type>(s.width);
+    y -= static_cast<Type>(s.height);
+    return *this;
+  }
+
+  template <class U>
+  inline TPoint operator*=(const TPoint<U>& p) {
+    x *= static_cast<Type>(p.x);
+    y *= static_cast<Type>(p.y);
+    return *this;
+  }
+
+  template <class U>
+  inline TPoint operator*=(const TSize<U>& s) {
+    x *= static_cast<Type>(s.width);
+    y *= static_cast<Type>(s.height);
+    return *this;
+  }
+
+  template <class U>
+  inline TPoint operator/=(const TPoint<U>& p) {
+    x /= static_cast<Type>(p.x);
+    y /= static_cast<Type>(p.y);
+    return *this;
+  }
+
+  template <class U>
+  inline TPoint operator/=(const TSize<U>& s) {
+    x /= static_cast<Type>(s.width);
+    y /= static_cast<Type>(s.height);
+    return *this;
+  }
+
   constexpr TPoint operator-() const { return {-x, -y}; }
 
   constexpr TPoint operator+(const TPoint& p) const {