Native window decorations:

- API to check whether current platform supports window decorations `FlatLaf.supportsNativeWindowDecorations()`
- API to toggle window decorations of all windows `FlatLaf.setUseNativeWindowDecorations(boolean)`
- `FlatClientProperties.USE_WINDOW_DECORATIONS` can now used to toggle window decorations for single window
- cleaned-up/fixed/simplified window decorations "enabled" checking:
  1. if `FlatSystemProperties.USE_WINDOW_DECORATIONS` is set, its value is used
  2. if `FlatClientProperties.USE_WINDOW_DECORATIONS` is set, its value is used
  3. use value of UI default `TitlePane.useWindowDecorations`

CHANGELOG.md

@@ -3,6 +3,13 @@ FlatLaf Change Log
 
 ## 1.2-SNAPSHOT
 
+#### New features and improvements
+
+- Native window decorations: Added API to check whether current platform
+  supports window decorations (`FlatLaf.supportsNativeWindowDecorations()`) and
+  to toggle window decorations of all windows
+  (`FlatLaf.setUseNativeWindowDecorations(boolean)`).
+
 #### Fixed bugs
 
 - Native window decorations: Fixed loading of native library when using Java

flatlaf-core/src/main/java/com/formdev/flatlaf/FlatClientProperties.java

@@ -233,10 +233,14 @@ public interface FlatClientProperties
 
 	/**
 	 * Specifies whether FlatLaf native window decorations should be used
-	 * when creating {@code JFrame} or {@code JDialog}.
+	 * for {@code JFrame} or {@code JDialog}.
 	 * <p>
-	 * Setting this to {@code false} disables using FlatLaf native window decorations
-	 * for the window that contains the root pane. Needs to be set before showing the window.
+	 * Setting this enables/disables using FlatLaf native window decorations
+	 * for the window that contains the root pane.
+	 * <p>
+	 * This client property has lower priority than system property
+	 * {@link FlatSystemProperties#USE_WINDOW_DECORATIONS}, but higher priority
+	 * than UI default {@code TitlePane.useWindowDecorations}.
 	 * <p>
 	 * (requires Window 10)
 	 * <p>

flatlaf-core/src/main/java/com/formdev/flatlaf/FlatLaf.java

@@ -46,6 +46,7 @@ import javax.swing.JDialog;
 import javax.swing.JFrame;
 import javax.swing.LookAndFeel;
 import javax.swing.PopupFactory;
+import javax.swing.RootPaneContainer;
 import javax.swing.SwingUtilities;
 import javax.swing.UIDefaults;
 import javax.swing.UIDefaults.ActiveValue;
@@ -59,6 +60,7 @@ import javax.swing.text.StyleContext;
 import javax.swing.text.html.HTMLEditorKit;
 import com.formdev.flatlaf.ui.FlatNativeWindowBorder;
 import com.formdev.flatlaf.ui.FlatPopupFactory;
+import com.formdev.flatlaf.ui.FlatRootPaneUI;
 import com.formdev.flatlaf.util.GrayFilter;
 import com.formdev.flatlaf.util.LoggingFacade;
 import com.formdev.flatlaf.util.MultiResolutionImageSupport;
@@ -715,6 +717,79 @@ public abstract class FlatLaf
 		} );
 	}
 
+	/**
+	 * Returns whether native window decorations are supported on current platform.
+	 * <p>
+	 * This requires Windows 10, but may be disabled if running in special environments
+	 * (JetBrains Projector, Webswing or WinPE) or if loading native library fails.
+	 * If system property {@link FlatSystemProperties#USE_WINDOW_DECORATIONS} is set to
+	 * {@code false}, then this method also returns {@code false}.
+	 *
+	 * @since 1.1.2
+	 */
+	public static boolean supportsNativeWindowDecorations() {
+		return SystemInfo.isWindows_10_orLater && FlatNativeWindowBorder.isSupported();
+	}
+
+	/**
+	 * Returns whether native window decorations are enabled.
+	 *
+	 * @since 1.1.2
+	 */
+	public static boolean isUseNativeWindowDecorations() {
+		return UIManager.getBoolean( "TitlePane.useWindowDecorations" );
+	}
+
+	/**
+	 * Sets whether native window decorations are enabled.
+	 * <p>
+	 * Existing frames and dialogs will be updated.
+	 *
+	 * @since 1.1.2
+	 */
+	public static void setUseNativeWindowDecorations( boolean enabled ) {
+		UIManager.put( "TitlePane.useWindowDecorations", enabled );
+
+		if( !(UIManager.getLookAndFeel() instanceof FlatLaf) )
+			return;
+
+		// update existing frames and dialogs
+		for( Window w : Window.getWindows() ) {
+			if( isDisplayableFrameOrDialog( w ) )
+				FlatRootPaneUI.updateNativeWindowBorder( ((RootPaneContainer)w).getRootPane() );
+		}
+	}
+
+	/**
+	 * Revalidate and repaint all displayable frames and dialogs.
+	 *
+	 * @since 1.1.2
+	 */
+	public static void revalidateAndRepaintAllFramesAndDialogs() {
+		for( Window w : Window.getWindows() ) {
+			if( isDisplayableFrameOrDialog( w ) ) {
+				w.revalidate();
+				w.repaint();
+			}
+		}
+	}
+
+	/**
+	 * Repaint all displayable frames and dialogs.
+	 *
+	 * @since 1.1.2
+	 */
+	public static void repaintAllFramesAndDialogs() {
+		for( Window w : Window.getWindows() ) {
+			if( isDisplayableFrameOrDialog( w ) )
+				w.repaint();
+		}
+	}
+
+	private static boolean isDisplayableFrameOrDialog( Window w ) {
+		return w.isDisplayable() && (w instanceof JFrame || w instanceof JDialog);
+	}
+
 	public static boolean isShowMnemonics() {
 		return MnemonicHandler.isShowMnemonics();
 	}

flatlaf-core/src/main/java/com/formdev/flatlaf/FlatSystemProperties.java

@@ -63,6 +63,10 @@ public interface FlatSystemProperties
 	 * <p>
 	 * Setting this to {@code false} disables using FlatLaf native window decorations.
 	 * <p>
+	 * This system property has higher priority than client property
+	 * {@link FlatClientProperties#USE_WINDOW_DECORATIONS} and
+	 * UI default {@code TitlePane.useWindowDecorations}.
+	 * <p>
 	 * (requires Window 10)
 	 * <p>
 	 * <strong>Allowed Values</strong> {@code false} and {@code true}<br>

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

@@ -99,18 +99,12 @@ public class FlatNativeWindowBorder
 
 		if( window instanceof JFrame ) {
 			JFrame frame = (JFrame) window;
+			JRootPane rootPane = frame.getRootPane();
 
-			// check whether disabled via client property
-			if( !FlatClientProperties.clientPropertyBoolean( frame.getRootPane(), FlatClientProperties.USE_WINDOW_DECORATIONS, true ) )
+			// check whether disabled via system property, client property or UI default
+			if( !useWindowDecorations( rootPane, systemPropertyKey ) )
 				return;
 
-			// do not enable native window border if JFrame should use system window decorations
-			// and if not forced to use FlatLaf/JBR native window decorations
-			if( !JFrame.isDefaultLookAndFeelDecorated() &&
-				!UIManager.getBoolean( "TitlePane.useWindowDecorations" ) &&
-				!FlatSystemProperties.getBoolean( systemPropertyKey, false ) )
-			  return;
-
 			// do not enable native window border if frame is undecorated
 			if( frame.isUndecorated() )
 				return;
@@ -119,22 +113,16 @@ public class FlatNativeWindowBorder
 			setHasCustomDecoration( frame, true );
 
 			// enable Swing window decoration
-			frame.getRootPane().setWindowDecorationStyle( JRootPane.FRAME );
+			rootPane.setWindowDecorationStyle( JRootPane.FRAME );
 
 		} else if( window instanceof JDialog ) {
 			JDialog dialog = (JDialog) window;
+			JRootPane rootPane = dialog.getRootPane();
 
-			// check whether disabled via client property
-			if( !FlatClientProperties.clientPropertyBoolean( dialog.getRootPane(), FlatClientProperties.USE_WINDOW_DECORATIONS, true ) )
+			// check whether disabled via system property, client property or UI default
+			if( !useWindowDecorations( rootPane, systemPropertyKey ) )
 				return;
 
-			// do not enable native window border if JDialog should use system window decorations
-			// and if not forced to use FlatLaf/JBR native window decorations
-			if( !JDialog.isDefaultLookAndFeelDecorated() &&
-				!UIManager.getBoolean( "TitlePane.useWindowDecorations" ) &&
-				!FlatSystemProperties.getBoolean( systemPropertyKey, false ) )
-			  return;
-
 			// do not enable native window border if dialog is undecorated
 			if( dialog.isUndecorated() )
 				return;
@@ -143,7 +131,7 @@ public class FlatNativeWindowBorder
 			setHasCustomDecoration( dialog, true );
 
 			// enable Swing window decoration
-			dialog.getRootPane().setWindowDecorationStyle( JRootPane.PLAIN_DIALOG );
+			rootPane.setWindowDecorationStyle( JRootPane.PLAIN_DIALOG );
 		}
 	}
 
@@ -153,12 +141,15 @@ public class FlatNativeWindowBorder
 			return;
 		}
 
+		if( !isSupported() )
+			return;
+
 		// remove listener
 		if( data instanceof PropertyChangeListener )
 			rootPane.removePropertyChangeListener( "ancestor", (PropertyChangeListener) data );
 
-		// do not uninstall when switching to another FlatLaf theme
-		if( UIManager.getLookAndFeel() instanceof FlatLaf )
+		// do not uninstall when switching to another FlatLaf theme and if still enabled
+		if( UIManager.getLookAndFeel() instanceof FlatLaf && useWindowDecorations( rootPane, FlatSystemProperties.USE_WINDOW_DECORATIONS ) )
 			return;
 
 		// uninstall native window border
@@ -188,6 +179,20 @@ public class FlatNativeWindowBorder
 		}
 	}
 
+	private static boolean useWindowDecorations( JRootPane rootPane, String systemPropertyKey ) {
+		// check whether forced to enabled/disabled via system property
+		Boolean enabled = FlatSystemProperties.getBooleanStrict( systemPropertyKey, null );
+		if( enabled != null )
+			return enabled;
+
+		// check whether forced to enabled/disabled via client property
+		enabled = FlatClientProperties.clientPropertyBooleanStrict( rootPane, FlatClientProperties.USE_WINDOW_DECORATIONS, null );
+		if( enabled != null )
+			return enabled;
+
+		return UIManager.getBoolean( "TitlePane.useWindowDecorations" );
+	}
+
 	public static boolean hasCustomDecoration( Window window ) {
 		if( canUseJBRCustomDecorations )
 			return JBRCustomDecorations.hasCustomDecoration( window );

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

@@ -95,7 +95,7 @@ public class FlatRootPaneUI
 		else
 			installBorder();
 
-		nativeWindowBorderData = FlatNativeWindowBorder.install( rootPane );
+		installNativeWindowBorder();
 	}
 
 	protected void installBorder() {
@@ -110,8 +110,7 @@ public class FlatRootPaneUI
 	public void uninstallUI( JComponent c ) {
 		super.uninstallUI( c );
 
-		FlatNativeWindowBorder.uninstall( rootPane, nativeWindowBorderData );
-
+		uninstallNativeWindowBorder();
 		uninstallClientDecorations();
 		rootPane = null;
 	}
@@ -137,6 +136,34 @@ public class FlatRootPaneUI
 			c.putClientProperty( "jetbrains.awt.windowDarkAppearance", FlatLaf.isLafDark() );
 	}
 
+	/**
+	 * @since 1.1.2
+	 */
+	protected void installNativeWindowBorder() {
+		nativeWindowBorderData = FlatNativeWindowBorder.install( rootPane );
+	}
+
+	/**
+	 * @since 1.1.2
+	 */
+	protected void uninstallNativeWindowBorder() {
+		FlatNativeWindowBorder.uninstall( rootPane, nativeWindowBorderData );
+		nativeWindowBorderData = null;
+	}
+
+	/**
+	 * @since 1.1.2
+	 */
+	public static void updateNativeWindowBorder( JRootPane rootPane ) {
+		RootPaneUI rui = rootPane.getUI();
+		if( !(rui instanceof FlatRootPaneUI) )
+			return;
+
+		FlatRootPaneUI ui = (FlatRootPaneUI) rui;
+		ui.uninstallNativeWindowBorder();
+		ui.installNativeWindowBorder();
+	}
+
 	protected void installClientDecorations() {
 		boolean isNativeWindowBorderSupported = FlatNativeWindowBorder.isSupported();
 
@@ -218,6 +245,10 @@ public class FlatRootPaneUI
 					installBorder();
 				break;
 
+			case FlatClientProperties.USE_WINDOW_DECORATIONS:
+				updateNativeWindowBorder( rootPane );
+				break;
+
 			case FlatClientProperties.MENU_BAR_EMBEDDED:
 				if( titlePane != null ) {
 					titlePane.menuBarChanged();

flatlaf-demo/src/main/java/com/formdev/flatlaf/demo/DemoFrame.java

@@ -24,7 +24,6 @@ import java.util.prefs.Preferences;
 import javax.swing.*;
 import javax.swing.text.DefaultEditorKit;
 import javax.swing.text.StyleContext;
-import com.formdev.flatlaf.FlatClientProperties;
 import com.formdev.flatlaf.FlatLaf;
 import com.formdev.flatlaf.demo.HintManager.Hint;
 import com.formdev.flatlaf.demo.extras.*;
@@ -35,7 +34,6 @@ import com.formdev.flatlaf.extras.FlatUIDefaultsInspector;
 import com.formdev.flatlaf.extras.components.FlatButton;
 import com.formdev.flatlaf.extras.components.FlatButton.ButtonType;
 import com.formdev.flatlaf.extras.FlatSVGUtils;
-import com.formdev.flatlaf.ui.FlatNativeWindowBorder;
 import com.formdev.flatlaf.ui.JBRCustomDecorations;
 import net.miginfocom.layout.ConstraintParser;
 import net.miginfocom.layout.LC;
@@ -144,35 +142,21 @@ class DemoFrame
 	private void windowDecorationsChanged() {
 		boolean windowDecorations = windowDecorationsCheckBoxMenuItem.isSelected();
 
-		// change window decoration of demo main frame
-		if( FlatNativeWindowBorder.isSupported() ) {
-			FlatNativeWindowBorder.setHasCustomDecoration( this, windowDecorations );
-			getRootPane().setWindowDecorationStyle( windowDecorations ? JRootPane.FRAME : JRootPane.NONE );
-		} else {
-			dispose();
-			setUndecorated( windowDecorations );
-			getRootPane().setWindowDecorationStyle( windowDecorations ? JRootPane.FRAME : JRootPane.NONE );
-			setVisible( true );
-		}
-		menuBarEmbeddedCheckBoxMenuItem.setEnabled( windowDecorations );
+		// change window decoration of all frames and dialogs
+		FlatLaf.setUseNativeWindowDecorations( windowDecorations );
 
-		// enable/disable window decoration for later created frames/dialogs
-		UIManager.put( "TitlePane.useWindowDecorations", windowDecorations );
+		menuBarEmbeddedCheckBoxMenuItem.setEnabled( windowDecorations );
+		unifiedTitleBarMenuItem.setEnabled( windowDecorations );
 	}
 
 	private void menuBarEmbeddedChanged() {
-		getRootPane().putClientProperty( FlatClientProperties.MENU_BAR_EMBEDDED,
-			menuBarEmbeddedCheckBoxMenuItem.isSelected() ? null : false );
-
-// alternative method for all frames and menu bars in an application
-//		UIManager.put( "TitlePane.menuBarEmbedded", menuBarEmbeddedCheckBoxMenuItem.isSelected() );
-//		revalidate();
-//		repaint();
+		UIManager.put( "TitlePane.menuBarEmbedded", menuBarEmbeddedCheckBoxMenuItem.isSelected() );
+		FlatLaf.revalidateAndRepaintAllFramesAndDialogs();
 	}
 
 	private void unifiedTitleBar() {
 		UIManager.put( "TitlePane.unifiedBackground", unifiedTitleBarMenuItem.isSelected() );
-		repaint();
+		FlatLaf.repaintAllFramesAndDialogs();
 	}
 
 	private void underlineMenuSelection() {
@@ -748,8 +732,7 @@ class DemoFrame
 		copyMenuItem.addActionListener( new DefaultEditorKit.CopyAction() );
 		pasteMenuItem.addActionListener( new DefaultEditorKit.PasteAction() );
 
-		boolean supportsWindowDecorations = UIManager.getLookAndFeel()
-			.getSupportsWindowDecorations() || FlatNativeWindowBorder.isSupported();
+		boolean supportsWindowDecorations = FlatLaf.supportsNativeWindowDecorations();
 
 		// If the JetBrainsRuntime is used, it forces the use of it's own custom
 		// window decoration, meaning we can't use our own.

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

@@ -35,8 +35,8 @@ import com.formdev.flatlaf.FlatIntelliJLaf;
 import com.formdev.flatlaf.FlatLaf;
 import com.formdev.flatlaf.FlatLightLaf;
 import com.formdev.flatlaf.extras.FlatInspector;
+import com.formdev.flatlaf.extras.components.FlatTriStateCheckBox;
 import com.formdev.flatlaf.ui.FlatLineBorder;
-import com.formdev.flatlaf.ui.FlatNativeWindowBorder;
 import com.formdev.flatlaf.util.SystemInfo;
 import net.miginfocom.swing.*;
 
@@ -304,13 +304,11 @@ public class FlatNativeWindowBorderTest
 	}
 
 	private void nativeChanged() {
-		FlatNativeWindowBorder.setHasCustomDecoration( window, nativeCheckBox.isSelected() );
+		FlatLaf.setUseNativeWindowDecorations( nativeCheckBox.isSelected() );
 	}
 
 	private void native2Changed() {
-		((RootPaneContainer)window).getRootPane().putClientProperty( FlatClientProperties.USE_WINDOW_DECORATIONS, native2CheckBox.isSelected() );
-		window.dispose();
-		window.setVisible( true );
+		((RootPaneContainer)window).getRootPane().putClientProperty( FlatClientProperties.USE_WINDOW_DECORATIONS, native2CheckBox.getChecked() );
 	}
 
 	private void revalidateLayout() {
@@ -382,7 +380,7 @@ public class FlatNativeWindowBorderTest
 		undecoratedCheckBox = new JCheckBox();
 		fullScreenCheckBox = new JCheckBox();
 		nativeCheckBox = new JCheckBox();
-		native2CheckBox = new JCheckBox();
+		native2CheckBox = new FlatTriStateCheckBox();
 		openDialogButton = new JButton();
 		hideWindowButton = new JButton();
 		reopenButton = new JButton();
@@ -446,7 +444,6 @@ public class FlatNativeWindowBorderTest
 
 		//---- native2CheckBox ----
 		native2CheckBox.setText("JRootPane.useWindowDecorations");
-		native2CheckBox.setSelected(true);
 		native2CheckBox.addActionListener(e -> native2Changed());
 		add(native2CheckBox, "cell 0 3 3 1");
 
@@ -507,7 +504,7 @@ public class FlatNativeWindowBorderTest
 	private JCheckBox undecoratedCheckBox;
 	private JCheckBox fullScreenCheckBox;
 	private JCheckBox nativeCheckBox;
-	private JCheckBox native2CheckBox;
+	private FlatTriStateCheckBox native2CheckBox;
 	private JButton openDialogButton;
 	private JButton hideWindowButton;
 	private JButton reopenButton;

flatlaf-testing/src/main/java/com/formdev/flatlaf/testing/FlatNativeWindowBorderTest.jfd

@@ -65,10 +65,9 @@ new FormModel {
 			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
 				"value": "cell 0 3 3 1"
 			} )
-			add( new FormComponent( "javax.swing.JCheckBox" ) {
+			add( new FormComponent( "com.formdev.flatlaf.extras.components.FlatTriStateCheckBox" ) {
 				name: "native2CheckBox"
 				"text": "JRootPane.useWindowDecorations"
-				"selected": true
 				addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "native2Changed", false ) )
 			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
 				"value": "cell 0 3 3 1"

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

@@ -35,17 +35,9 @@ public class FlatWindowDecorationsTest
 {
 	public static void main( String[] args ) {
 		SwingUtilities.invokeLater( () -> {
-			// enable custom window decoration (if LaF supports it)
-			JFrame.setDefaultLookAndFeelDecorated( true );
-			JDialog.setDefaultLookAndFeelDecorated( true );
-
 			FlatTestFrame frame = FlatTestFrame.create( args, "FlatWindowDecorationsTest" );
 			frame.applyComponentOrientationToFrame = true;
 
-			// WARNING: Do not this in real-world programs.
-//			frame.setUndecorated( true );
-//			frame.getRootPane().setWindowDecorationStyle( JRootPane.FRAME );
-
 			Class<?> cls = FlatWindowDecorationsTest.class;
 			List<Image> images = Arrays.asList(
 				new ImageIcon( cls.getResource( "/com/formdev/flatlaf/testing/test16.png" ) ).getImage(),