fixed AWT components on macOS (issue #583)

- fixed missing focus indicator
- fixed round corners
- fixed java.awt.Button background
- fixed java.awt.Choice background
- fixed java.awt.Checkbox hover

CHANGELOG.md

@@ -18,6 +18,8 @@ FlatLaf Change Log
 - Fixed missing UI value `MenuItem.acceleratorDelimiter` on macOS. (was `null`,
   is now an empty string)
 - Fixed possible exception in `FlatUIUtils.resetRenderingHints()`. (issue #575)
+- Fixed AWT components on macOS, which use Swing components internally. (issue
+  #583)
 
 
 ## 2.4

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatButtonUI.java

@@ -629,6 +629,9 @@ public class FlatButtonUI
 	}
 
 	protected Color getBackgroundBase( JComponent c, boolean def ) {
+		if( FlatUIUtils.isAWTPeer( c ) )
+			return background;
+
 		// use component background if explicitly set
 		Color bg = c.getBackground();
 		if( isCustomBackground( bg ) )

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatComboBoxUI.java

@@ -631,6 +631,9 @@ public class FlatComboBoxUI
 
 	protected Color getBackground( boolean enabled ) {
 		if( enabled ) {
+			if( FlatUIUtils.isAWTPeer( comboBox ) )
+				return UIManager.getColor( "ComboBox.background" );
+
 			Color background = comboBox.getBackground();
 
 			// always use explicitly set color

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatRadioButtonUI.java

@@ -18,12 +18,16 @@ package com.formdev.flatlaf.ui;
 
 import static com.formdev.flatlaf.util.UIScale.scale;
 import java.awt.Color;
+import java.awt.Component;
 import java.awt.Container;
 import java.awt.Dimension;
 import java.awt.Graphics;
 import java.awt.Insets;
 import java.awt.Rectangle;
+import java.awt.event.MouseAdapter;
+import java.awt.event.MouseEvent;
 import java.beans.PropertyChangeEvent;
+import java.beans.PropertyChangeListener;
 import java.util.Map;
 import java.util.Objects;
 import javax.swing.AbstractButton;
@@ -31,6 +35,7 @@ import javax.swing.CellRendererPane;
 import javax.swing.Icon;
 import javax.swing.JComponent;
 import javax.swing.LookAndFeel;
+import javax.swing.SwingUtilities;
 import javax.swing.UIManager;
 import javax.swing.plaf.ComponentUI;
 import javax.swing.plaf.basic.BasicButtonListener;
@@ -92,9 +97,20 @@ public class FlatRadioButtonUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
+		if( FlatUIUtils.isAWTPeer( c ) )
+			AWTPeerMouseExitedFix.install( c );
+
 		installStyle( (AbstractButton) c );
 	}
 
+	@Override
+	public void uninstallUI( JComponent c ) {
+		super.uninstallUI( c );
+
+		if( FlatUIUtils.isAWTPeer( c ) )
+			AWTPeerMouseExitedFix.uninstall( c );
+	}
+
 	@Override
 	public void installDefaults( AbstractButton b ) {
 		super.installDefaults( b );
@@ -321,4 +337,69 @@ public class FlatRadioButtonUI
 			FlatRadioButtonUI.this.propertyChange( b, e );
 		}
 	}
+
+	//---- class AWTPeerMouseExitedFix ----------------------------------------
+
+	/**
+	 * Hack for missing mouse-exited event for java.awt.Checkbox on macOS (to fix hover effect).
+	 *
+	 * On macOS, AWT components internally use Swing components.
+	 * This is implemented in class sun.lwawt.LWCheckboxPeer, which uses
+	 * a container component CheckboxDelegate that has a JCheckBox and a JRadioButton
+	 * as children. Only one of them is visible.
+	 *
+	 * The reason that mouse-exited event is not sent to the JCheckBox or JRadioButton
+	 * is that sun.lwawt.LWComponentPeer.createDelegateEvent() uses
+	 * SwingUtilities.getDeepestComponentAt() to find the event target,
+	 * which finds the container component CheckboxDelegate,
+	 * which receives the mouse-exited event.
+	 *
+	 * This class adds listeners and forwards the mouse-exited event
+	 * from CheckboxDelegate to JCheckBox or JRadioButton.
+	 */
+	private static class AWTPeerMouseExitedFix
+		extends MouseAdapter
+		implements PropertyChangeListener
+	{
+		private final JComponent button;
+
+		static void install( JComponent button ) {
+			AWTPeerMouseExitedFix l = new AWTPeerMouseExitedFix( button );
+			button.addPropertyChangeListener( "ancestor", l );
+			Container parent = button.getParent();
+			if( parent != null )
+				parent.addMouseListener( l );
+		}
+
+		static void uninstall( JComponent button ) {
+			for( PropertyChangeListener l : button.getPropertyChangeListeners( "ancestor" ) ) {
+				if( l instanceof AWTPeerMouseExitedFix ) {
+					button.removePropertyChangeListener( "ancestor", l );
+					Container parent = button.getParent();
+					if( parent != null )
+						parent.removeMouseListener( (AWTPeerMouseExitedFix) l );
+					break;
+				}
+			}
+		}
+
+		AWTPeerMouseExitedFix( JComponent button ) {
+			this.button = button;
+		}
+
+		@Override
+		public void propertyChange( PropertyChangeEvent e ) {
+			if( e.getOldValue() instanceof Component )
+				((Component)e.getOldValue()).removeMouseListener( this );
+			if( e.getNewValue() instanceof Component ) {
+				((Component)e.getNewValue()).removeMouseListener( this ); // avoid duplicate listeners
+				((Component)e.getNewValue()).addMouseListener( this );
+			}
+		}
+
+		@Override
+		public void mouseExited( MouseEvent e ) {
+			button.dispatchEvent( SwingUtilities.convertMouseEvent( e.getComponent(), e, button ) );
+		}
+	}
 }

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatUIUtils.java

@@ -59,6 +59,7 @@ import com.formdev.flatlaf.FlatSystemProperties;
 import com.formdev.flatlaf.util.DerivedColor;
 import com.formdev.flatlaf.util.Graphics2DProxy;
 import com.formdev.flatlaf.util.HiDPIUtils;
+import com.formdev.flatlaf.util.SystemInfo;
 import com.formdev.flatlaf.util.UIScale;
 
 /**
@@ -241,6 +242,11 @@ public class FlatUIUtils
 			}
 		}
 
+		// invoke hasFocus() here because components may have overridden this method
+		// (e.g. Swing delegate components used for AWT components on macOS)
+		if( c.hasFocus() )
+			return true;
+
 		return keyboardFocusManager.getPermanentFocusOwner() == c &&
 			isInActiveWindow( c, keyboardFocusManager.getActiveWindow() );
 	}
@@ -251,6 +257,13 @@ public class FlatUIUtils
 			(window != null && window.getType() == Window.Type.POPUP && window.getOwner() == activeWindow);
 	}
 
+	static boolean isAWTPeer( JComponent c ) {
+		// on macOS, Swing components are used for AWT components
+		if( SystemInfo.isMacOS )
+			return c.getClass().getName().startsWith( "sun.lwawt.LW" );
+		return false;
+	}
+
 	/**
 	 * Returns whether the given component is in a window that is in full-screen mode.
 	 */
@@ -335,7 +348,7 @@ public class FlatUIUtils
 	 */
 	public static Object[] setRenderingHints( Graphics g ) {
 		Graphics2D g2 = (Graphics2D) g;
-		Object[] oldRenderingHints = new Object[] {
+		Object[] oldRenderingHints = {
 			g2.getRenderingHint( RenderingHints.KEY_ANTIALIASING ),
 			g2.getRenderingHint( RenderingHints.KEY_STROKE_CONTROL ),
 		};
@@ -378,7 +391,7 @@ public class FlatUIUtils
 		}
 
 		Graphics2D g2 = (Graphics2D) g;
-		Object[] oldRenderingHints2 = new Object[] {
+		Object[] oldRenderingHints2 = {
 			g2.getRenderingHint( RenderingHints.KEY_ANTIALIASING ),
 			g2.getRenderingHint( RenderingHints.KEY_STROKE_CONTROL ),
 		};
@@ -666,9 +679,9 @@ public class FlatUIUtils
 	 * is smaller than its bounds (for the focus decoration).
 	 */
 	public static void paintParentBackground( Graphics g, JComponent c ) {
-		Container parent = findOpaqueParent( c );
-		if( parent != null ) {
-			g.setColor( parent.getBackground() );
+		Color background = getParentBackground( c );
+		if( background != null ) {
+			g.setColor( background );
 			g.fillRect( 0, 0, c.getWidth(), c.getHeight() );
 		}
 	}
@@ -678,9 +691,10 @@ public class FlatUIUtils
 	 */
 	public static Color getParentBackground( JComponent c ) {
 		Container parent = findOpaqueParent( c );
-		return (parent != null)
-			? parent.getBackground()
-			: UIManager.getColor( "Panel.background" ); // fallback, probably never used
+		// parent.getBackground() may return null
+		// (e.g. for Swing delegate components used for AWT components on macOS)
+		Color background = (parent != null) ? parent.getBackground() : null;
+		return (background != null) ? background : UIManager.getColor( "Panel.background" );
 	}
 
 	/**

flatlaf-testing/src/main/java/com/formdev/flatlaf/testing/FlatAWTTest.java

@@ -17,8 +17,11 @@
 package com.formdev.flatlaf.testing;
 
 import java.awt.*;
+import java.awt.event.MouseAdapter;
+import java.awt.event.MouseEvent;
 import java.awt.event.WindowAdapter;
 import java.awt.event.WindowEvent;
+import javax.swing.SwingUtilities;
 import com.formdev.flatlaf.FlatLightLaf;
 
 /**
@@ -69,6 +72,52 @@ public class FlatAWTTest
 			frame.add( new Panel() );
 			frame.add( new Canvas() );
 
+			Panel controlPanel = new Panel();
+			frame.add( controlPanel );
+
+			Checkbox enabledCheckBox = new Checkbox( "enabled", true );
+			enabledCheckBox.addItemListener( e -> {
+				boolean enabled = enabledCheckBox.getState();
+				for( Component c : frame.getComponents() ) {
+					if( c != controlPanel )
+						c.setEnabled( enabled );
+				}
+			} );
+			controlPanel.add( enabledCheckBox );
+
+			Checkbox explicitColorsCheckBox = new Checkbox( "explicit colors" );
+			explicitColorsCheckBox.addItemListener( e -> {
+				boolean explicit = explicitColorsCheckBox.getState();
+				for( Component c : frame.getComponents() ) {
+					if( c != controlPanel )
+						c.setBackground( explicit ? Color.green : null );
+				}
+			} );
+			controlPanel.add( explicitColorsCheckBox );
+
+			Menu menu = new Menu( "File" );
+			menu.add( new MenuItem( "New" ) );
+			menu.add( new MenuItem( "Open" ) );
+			menu.add( new MenuItem( "Save" ) );
+
+			MenuBar menuBar = new MenuBar();
+			menuBar.add( menu );
+			frame.setMenuBar( menuBar );
+
+			PopupMenu popupMenu = new PopupMenu();
+			popupMenu.add( new MenuItem( "item 1" ) );
+			popupMenu.add( new MenuItem( "item 2" ) );
+			popupMenu.add( new MenuItem( "item 3" ) );
+			list.add( popupMenu );
+			list.addMouseListener( new MouseAdapter() {
+				@Override
+				public
+				void mousePressed( MouseEvent e ) {
+					if( SwingUtilities.isRightMouseButton( e ) )
+						popupMenu.show( list, 0, 0 );
+				}
+			} );
+
 			frame.setSize( 800, 600 );
 			frame.setVisible( true );
 		});