Rect: Add clamp() method

Resolves: #527

Author: adazem009

src/rect.cpp

@@ -88,6 +88,21 @@ void Rect::snapToInt()
     impl->top = std::ceil(impl->top);
 }
 
+/*! Clamps the rectangle to the given bounds. */
+void Rect::clamp(double left, double top, double right, double bottom)
+{
+    // https://github.com/scratchfoundation/scratch-render/blob/c3ede9c3d54769730c7b023021511e2aba167b1f/src/Rectangle.js#L121-L131
+    impl->left = std::max(impl->left, left);
+    impl->right = std::min(impl->right, right);
+    impl->bottom = std::max(impl->bottom, bottom);
+    impl->top = std::min(impl->top, top);
+
+    impl->left = std::min(impl->left, right);
+    impl->right = std::max(impl->right, left);
+    impl->bottom = std::min(impl->bottom, top);
+    impl->top = std::max(impl->top, bottom);
+}
+
 /*! Returns true if the rectangle intersects the given rectangle. */
 bool Rect::intersects(const Rect &rect) const
 {

test/rect/rect_test.cpp

@@ -268,3 +268,69 @@ TEST(RectTest, Contains)
     ASSERT_TRUE(rect_ydown.contains(0, -40));
     ASSERT_TRUE(rect_ydown.contains(5, 24));
 }
+
+TEST(RectTest, Clamp)
+{
+    {
+        Rect rect(-50, 25, 150, -75);
+        rect.clamp(-40, 30, 160, -80);
+        ASSERT_EQ(rect.left(), -40);
+        ASSERT_EQ(rect.top(), 25);
+        ASSERT_EQ(rect.right(), 150);
+        ASSERT_EQ(rect.bottom(), -75);
+    }
+
+    {
+        Rect rect(-50, 25, 150, -75);
+        rect.clamp(-50, 24, 160, -75);
+        ASSERT_EQ(rect.left(), -50);
+        ASSERT_EQ(rect.top(), 24);
+        ASSERT_EQ(rect.right(), 150);
+        ASSERT_EQ(rect.bottom(), -75);
+    }
+
+    {
+        Rect rect(-50, 25, 150, -75);
+        rect.clamp(-50, 25, 145, -75);
+        ASSERT_EQ(rect.left(), -50);
+        ASSERT_EQ(rect.top(), 25);
+        ASSERT_EQ(rect.right(), 145);
+        ASSERT_EQ(rect.bottom(), -75);
+    }
+
+    {
+        Rect rect(-50, 25, 150, -75);
+        rect.clamp(-50, 25, 150, -68);
+        ASSERT_EQ(rect.left(), -50);
+        ASSERT_EQ(rect.top(), 25);
+        ASSERT_EQ(rect.right(), 150);
+        ASSERT_EQ(rect.bottom(), -68);
+    }
+
+    {
+        Rect rect(-50, 25, 150, -75);
+        rect.clamp(-100, 10, 50, -120);
+        ASSERT_EQ(rect.left(), -50);
+        ASSERT_EQ(rect.top(), 10);
+        ASSERT_EQ(rect.right(), 50);
+        ASSERT_EQ(rect.bottom(), -75);
+    }
+
+    {
+        Rect rect(-50, 25, 150, -75);
+        rect.clamp(-100, 30, 160, -120);
+        ASSERT_EQ(rect.left(), -50);
+        ASSERT_EQ(rect.top(), 25);
+        ASSERT_EQ(rect.right(), 150);
+        ASSERT_EQ(rect.bottom(), -75);
+    }
+
+    {
+        Rect rect(-50, 25, 150, -75);
+        rect.clamp(-50, 25, 150, -75);
+        ASSERT_EQ(rect.left(), -50);
+        ASSERT_EQ(rect.top(), 25);
+        ASSERT_EQ(rect.right(), 150);
+        ASSERT_EQ(rect.bottom(), -75);
+    }
+}