AudioProcessorEditor: Add method to configure layer-backedness of plugin editors

modules/juce_audio_processors/processors/juce_AudioProcessorEditor.cpp

@@ -225,4 +225,16 @@ ComponentPeer* AudioProcessorEditor::createNewPeer ([[maybe_unused]] int styleFl
     return Component::createNewPeer (styleFlags, nativeWindow);
 }
 
+bool AudioProcessorEditor::wantsLayerBackedView() const
+{
+   #if JUCE_MODULE_AVAILABLE_juce_opengl && JUCE_MAC
+    if (@available (macOS 10.14, *))
+        return true;
+
+    return false;
+   #else
+    return true;
+   #endif
+}
+
 } // namespace juce

modules/juce_audio_processors/processors/juce_AudioProcessorEditor.h

@@ -206,6 +206,23 @@ public:
     */
     std::unique_ptr<ResizableCornerComponent> resizableCorner;
 
+    /** The plugin wrapper will call this function to decide whether to use a layer-backed view to
+        host the editor on macOS and iOS.
+
+        Layer-backed views generally provide better performance, and are recommended in most
+        situations. However, on older macOS versions (confirmed on 10.12 and 10.13), displaying an
+        OpenGL context inside a layer-backed view can lead to deadlocks, so it is recommended to
+        avoid layer-backed views when using OpenGL on these OS versions.
+
+        The default behaviour of this function is to return false if and only if the juce_opengl
+        module is present and the current platform is macOS 10.13 or earlier.
+
+        You may want to override this behaviour if your plugin has an option to enable and disable
+        OpenGL rendering. If you know your plugin editor will never use OpenGL rendering, you can
+        set this function to return true in all situations.
+    */
+    virtual bool wantsLayerBackedView() const;
+
 private:
     //==============================================================================
     struct AudioProcessorEditorListener : public ComponentListener