Allow resizing the playground.

Author: chinmaygarde

impeller/playground/playground.h

@@ -33,9 +33,12 @@ class Playground : public ::testing::Test {
  private:
   Renderer renderer_;
   Point cursor_position_;
+  ISize window_size_ = ISize{1024, 768};
 
   void SetCursorPosition(Point pos);
 
+  void SetWindowSize(ISize size);
+
   FML_DISALLOW_COPY_AND_ASSIGN(Playground);
 };
 

impeller/playground/playground.mm

@@ -78,7 +78,7 @@ static void PlaygroundKeyCallback(GLFWwindow* window,
 }
 
 ISize Playground::GetWindowSize() const {
-  return {1024, 768};
+  return window_size_;
 }
 
 void Playground::SetCursorPosition(Point pos) {
@@ -100,10 +100,6 @@ static void PlaygroundKeyCallback(GLFWwindow* window,
   fml::ScopedCleanupClosure terminate([]() { ::glfwTerminate(); });
 
   ::glfwWindowHint(GLFW_CLIENT_API, GLFW_NO_API);
-  // Recreation of the target render buffer is not setup in the playground yet.
-  // So prevent users from resizing and getting confused that their math is
-  // wrong.
-  ::glfwWindowHint(GLFW_RESIZABLE, false);
 
   auto window_title = GetWindowTitle(flutter::testing::GetCurrentTestName());
   auto window =
@@ -114,6 +110,16 @@ static void PlaygroundKeyCallback(GLFWwindow* window,
   }
 
   ::glfwSetWindowUserPointer(window, this);
+  ::glfwSetWindowSizeCallback(
+      window, [](GLFWwindow* window, int width, int height) -> void {
+        auto playground =
+            reinterpret_cast<Playground*>(::glfwGetWindowUserPointer(window));
+        if (!playground) {
+          return;
+        }
+        playground->SetWindowSize(
+            ISize{std::max(width, 0), std::max(height, 0)});
+      });
   ::glfwSetKeyCallback(window, &PlaygroundKeyCallback);
   ::glfwSetCursorPosCallback(window, [](GLFWwindow* window, double x,
                                         double y) {
@@ -138,6 +144,11 @@ static void PlaygroundKeyCallback(GLFWwindow* window,
       return true;
     }
 
+    const auto layer_size = layer.bounds.size;
+    const auto layer_scale = layer.contentsScale;
+    layer.drawableSize = CGSizeMake(layer_size.width * layer_scale,
+                                    layer_size.height * layer_scale);
+
     Renderer::RenderCallback wrapped_callback = [render_callback](auto& pass) {
       pass.SetLabel("Playground Main Render Pass");
       return render_callback(pass);
@@ -193,4 +204,8 @@ CompressedImage compressed_image(
   return texture;
 }
 
+void Playground::SetWindowSize(ISize size) {
+  window_size_ = size;
+}
+
 }  // namespace impeller