Window decorations: support unified backgrounds for window title bar, menu bar and main content (issue #254)

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

@@ -23,14 +23,16 @@ import javax.swing.ActionMap;
 import javax.swing.JComponent;
 import javax.swing.JMenu;
 import javax.swing.JMenuBar;
+import javax.swing.JRootPane;
 import javax.swing.LookAndFeel;
 import javax.swing.MenuElement;
 import javax.swing.MenuSelectionManager;
 import javax.swing.SwingUtilities;
+import javax.swing.UIManager;
 import javax.swing.plaf.ActionMapUIResource;
 import javax.swing.plaf.ComponentUI;
+import javax.swing.plaf.UIResource;
 import javax.swing.plaf.basic.BasicMenuBarUI;
-import com.formdev.flatlaf.FlatClientProperties;
 import com.formdev.flatlaf.FlatLaf;
 import com.formdev.flatlaf.util.SystemInfo;
 
@@ -43,12 +45,15 @@ import com.formdev.flatlaf.util.SystemInfo;
  * @uiDefault MenuBar.background						Color
  * @uiDefault MenuBar.foreground						Color
  * @uiDefault MenuBar.border							Border
+ * @uiDefault TitlePane.unifiedBackground				boolean
  *
  * @author Karl Tauber
  */
 public class FlatMenuBarUI
 	extends BasicMenuBarUI
 {
+	protected boolean unifiedBackground;
+
 	public static ComponentUI createUI( JComponent c ) {
 		return new FlatMenuBarUI();
 	}
@@ -63,6 +68,8 @@ public class FlatMenuBarUI
 		super.installDefaults();
 
 		LookAndFeel.installProperty( menuBar, "opaque", false );
+
+		unifiedBackground = UIManager.getBoolean( "TitlePane.unifiedBackground" );
 	}
 
 	@Override
@@ -80,9 +87,7 @@ public class FlatMenuBarUI
 	@Override
 	public void update( Graphics g, JComponent c ) {
 		// do not fill background if menubar is embedded into title pane
-		if( c.isOpaque() ||
-			!FlatClientProperties.clientPropertyBoolean( menuBar, "flatlaf.internal.menuBarEmbedded", false ) )
-		{
+		if( isFillBackground( c ) ) {
 			g.setColor( c.getBackground() );
 			g.fillRect( 0, 0, c.getWidth(), c.getHeight() );
 		}
@@ -90,6 +95,24 @@ public class FlatMenuBarUI
 		paint( g, c );
 	}
 
+	protected boolean isFillBackground( JComponent c ) {
+		// paint background in opaque or having custom background color
+		if( c.isOpaque() || !(c.getBackground() instanceof UIResource) )
+			return true;
+
+		// do not paint background for unified title pane
+		if( unifiedBackground )
+			return false;
+
+		// paint background in full screen mode
+		JRootPane rootPane = SwingUtilities.getRootPane( c );
+		if( rootPane == null || FlatUIUtils.isFullScreen( rootPane ) )
+			return true;
+
+		// do not paint background if menu bar is embedded into title pane
+		return rootPane.getJMenuBar() != c || !FlatRootPaneUI.isMenuBarEmbedded( rootPane );
+	}
+
 	//---- class TakeFocus ----------------------------------------------------
 
 	/**

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

@@ -40,6 +40,7 @@ import javax.swing.UIManager;
 import javax.swing.border.Border;
 import javax.swing.plaf.BorderUIResource;
 import javax.swing.plaf.ComponentUI;
+import javax.swing.plaf.RootPaneUI;
 import javax.swing.plaf.UIResource;
 import javax.swing.plaf.basic.BasicRootPaneUI;
 import com.formdev.flatlaf.FlatClientProperties;
@@ -227,6 +228,13 @@ public class FlatRootPaneUI
 		}
 	}
 
+	protected static boolean isMenuBarEmbedded( JRootPane rootPane ) {
+		RootPaneUI ui = rootPane.getUI();
+		return ui instanceof FlatRootPaneUI &&
+			((FlatRootPaneUI)ui).titlePane != null &&
+			((FlatRootPaneUI)ui).titlePane.isMenuBarEmbedded();
+	}
+
 	//---- class FlatRootLayout -----------------------------------------------
 
 	protected class FlatRootLayout
@@ -297,10 +305,10 @@ public class FlatRootPaneUI
 				rootPane.getGlassPane().setBounds( x, y, width, height );
 
 			int nextY = 0;
-			if( !isFullScreen && titlePane != null ) {
-				Dimension prefSize = titlePane.getPreferredSize();
-				titlePane.setBounds( 0, 0, width, prefSize.height );
-				nextY += prefSize.height;
+			if( titlePane != null ) {
+				int prefHeight = !isFullScreen ? titlePane.getPreferredSize().height : 0;
+				titlePane.setBounds( 0, 0, width, prefHeight );
+				nextY += prefHeight;
 			}
 
 			JMenuBar menuBar = rootPane.getJMenuBar();
@@ -314,9 +322,6 @@ public class FlatRootPaneUI
 					menuBar.setBounds( 0, nextY, width, prefSize.height );
 					nextY += prefSize.height;
 				}
-
-				// mark menubar as embedded, which is used when painting menubar background
-				menuBar.putClientProperty( "flatlaf.internal.menuBarEmbedded", embedded ? true : null );
 			}
 
 			Container contentPane = rootPane.getContentPane();
@@ -346,6 +351,9 @@ public class FlatRootPaneUI
 
 	//---- class FlatWindowBorder ---------------------------------------------
 
+	/**
+	 * Window border used for non-native window decorations.
+	 */
 	public static class FlatWindowBorder
 		extends BorderUIResource.EmptyBorderUIResource
 	{
@@ -360,7 +368,7 @@ public class FlatRootPaneUI
 		@Override
 		public Insets getBorderInsets( Component c, Insets insets ) {
 			if( isWindowMaximized( c ) || FlatUIUtils.isFullScreen( c ) ) {
-				// hide border if window is maximized
+				// hide border if window is maximized or full screen
 				insets.top = insets.left = insets.bottom = insets.right = 0;
 				return insets;
 			} else

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

@@ -78,6 +78,7 @@ import com.formdev.flatlaf.util.UIScale;
  * @uiDefault TitlePane.inactiveForeground					Color
  * @uiDefault TitlePane.embeddedForeground					Color
  * @uiDefault TitlePane.borderColor							Color	optional
+ * @uiDefault TitlePane.unifiedBackground					boolean
  * @uiDefault TitlePane.iconSize							Dimension
  * @uiDefault TitlePane.iconMargins							Insets
  * @uiDefault TitlePane.titleMargins						Insets
@@ -103,6 +104,7 @@ public class FlatTitlePane
 	protected final Color embeddedForeground = UIManager.getColor( "TitlePane.embeddedForeground" );
 	protected final Color borderColor = UIManager.getColor( "TitlePane.borderColor" );
 
+	protected final boolean unifiedBackground = UIManager.getBoolean( "TitlePane.unifiedBackground" );
 	protected final Dimension iconSize = UIManager.getDimension( "TitlePane.iconSize" );
 	protected final int buttonMaximizedHeight = UIManager.getInt( "TitlePane.buttonMaximizedHeight" );
 	protected final boolean centerTitle = UIManager.getBoolean( "TitlePane.centerTitle" );
@@ -511,8 +513,10 @@ debug*/
 
 	@Override
 	protected void paintComponent( Graphics g ) {
-		g.setColor( getBackground() );
-		g.fillRect( 0, 0, getWidth(), getHeight() );
+		if( !unifiedBackground ) {
+			g.setColor( getBackground() );
+			g.fillRect( 0, 0, getWidth(), getHeight() );
+		}
 	}
 
 	protected void repaintWindowBorder() {

flatlaf-core/src/main/resources/com/formdev/flatlaf/FlatLaf.properties

@@ -687,6 +687,7 @@ TitledBorder.border = 1,1,1,1,$Separator.foreground
 
 TitlePane.useWindowDecorations = true
 TitlePane.menuBarEmbedded = true
+TitlePane.unifiedBackground = false
 TitlePane.iconSize = 16,16
 TitlePane.iconMargins = 3,8,3,8
 TitlePane.titleMargins = 3,0,3,0