Add support for JComponent.titleBarCaption for macOS

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

@@ -296,6 +296,8 @@ public interface FlatClientProperties
 	 *       and should therefore return quickly.
 	 *   <li>This function is invoked on 'AWT-Windows' thread (not 'AWT-EventQueue' thread)
 	 *       while processing Windows messages.
+	 *       On macOS in fullWindowContent mode (since 3.7.2), it is invoked on the AppKit
+	 *       main thread before the mouse event is dispatched to AWT.
 	 *       It <b>must not</b> change any component property or layout because this could cause a dead lock.
 	 * </ul>
 	 * <p>

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

@@ -45,7 +45,7 @@
  */
 public class FlatNativeMacLibrary
 {
-	private static int API_VERSION_MACOS = 2004;
+	private static int API_VERSION_MACOS = 2005;
 
 	/**
 	 * Checks whether native library is loaded/available.
@@ -71,6 +71,41 @@ public static boolean isLoaded() {
 	/** @since 3.4 */ public native static boolean isWindowFullScreen( Window window );
 	/** @since 3.4 */ public native static boolean toggleWindowFullScreen( Window window );
 
+	/**
+	 * Registers a hit-test callback used to decide whether a left mouse down event
+	 * in a fullWindowContent macOS window's title bar area should start a native
+	 * window drag instead of being delivered to AWT.
+	 * <p>
+	 * The window must already use {@code apple.awt.fullWindowContent=true}.
+	 * Passing the same window twice replaces the previously registered callback.
+	 *
+	 * @since 3.7.2
+	 */
+	public native static boolean setupFullWindowContentTitleBarCaption( Window window, FullWindowContentTitleBarCaptionCallback callback );
+
+	/**
+	 * Removes the callback previously installed with
+	 * {@link #setupFullWindowContentTitleBarCaption(Window, FullWindowContentTitleBarCaptionCallback)}.
+	 *
+	 * @since 3.7.2
+	 */
+	public native static boolean removeFullWindowContentTitleBarCaption( Window window );
+
+	/** @since 3.7.2 */
+	public interface FullWindowContentTitleBarCaptionCallback {
+		/**
+		 * Invoked on the AppKit main thread (not the AWT event dispatching thread)
+		 * before the mouse event is dispatched to AWT.
+		 * It <b>must not</b> change any component property or layout because this could cause a dead lock.
+		 *
+		 * @param x x coordinate in AWT window coordinates (origin top-left)
+		 * @param y y coordinate in AWT window coordinates (origin top-left)
+		 * @return {@code true} if the location should behave as title bar caption
+		 *         (i.e. start a native window drag instead of being delivered to AWT)
+		 */
+		boolean isTitleBarCaptionAt( int x, int y );
+	}
+
 
 	/** @since 3.7 */
 	public static final int

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

@@ -199,8 +199,11 @@ protected void uninstallDefaults( JRootPane c ) {
 	protected void installListeners( JRootPane root ) {
 		super.installListeners( root );
 
-		if( SystemInfo.isMacFullWindowContentSupported )
+		if( SystemInfo.isMacFullWindowContentSupported ) {
 			macFullWindowContentListener = FullWindowContentSupport.macInstallListeners( root );
+			if( FlatClientProperties.clientPropertyBoolean( root, "apple.awt.fullWindowContent", false ) )
+				FullWindowContentSupport.macInstallTitleBarCaption( root );
+		}
 		macInstallWindowBackgroundListener( root );
 	}
 
@@ -210,6 +213,7 @@ protected void uninstallListeners( JRootPane root ) {
 
 		if( SystemInfo.isMacFullWindowContentSupported ) {
 			FullWindowContentSupport.macUninstallListeners( root, macFullWindowContentListener );
+			FullWindowContentSupport.macUninstallTitleBarCaption( root );
 			macFullWindowContentListener = null;
 		}
 		macUninstallWindowBackgroundListener( root );
@@ -536,17 +540,27 @@ public void propertyChange( PropertyChangeEvent e ) {
 				// "apple.awt.fullWindowContent" or FlatClientProperties.MACOS_WINDOW_BUTTONS_SPACING
 				// is usually done before the native window is created
 				// --> try again when native window is created
-				if( e.getNewValue() instanceof Window )
+				if( e.getNewValue() instanceof Window ) {
 					macInstallFullWindowContentSupport();
+					// title bar caption support also requires a native window
+					if( SystemInfo.isMacFullWindowContentSupported &&
+						FlatClientProperties.clientPropertyBoolean( rootPane, "apple.awt.fullWindowContent", false ) )
+						FullWindowContentSupport.macInstallTitleBarCaption( rootPane );
+				}
 				break;
 
 			case FlatClientProperties.MACOS_WINDOW_BUTTONS_SPACING:
 				macInstallFullWindowContentSupport();
 				break;
 
 			case "apple.awt.fullWindowContent":
-				if( SystemInfo.isMacFullWindowContentSupported )
+				if( SystemInfo.isMacFullWindowContentSupported ) {
 					FullWindowContentSupport.macUpdateFullWindowContentButtonsBoundsProperty( rootPane );
+					if( FlatClientProperties.clientPropertyBoolean( rootPane, "apple.awt.fullWindowContent", false ) )
+						FullWindowContentSupport.macInstallTitleBarCaption( rootPane );
+					else
+						FullWindowContentSupport.macUninstallTitleBarCaption( rootPane );
+				}
 				break;
 		}
 	}

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

@@ -48,7 +48,6 @@
 import java.beans.PropertyChangeListener;
 import java.util.List;
 import java.util.Objects;
-import java.util.function.Function;
 import javax.accessibility.AccessibleContext;
 import javax.swing.BorderFactory;
 import javax.swing.Box;
@@ -65,7 +64,6 @@
 import javax.swing.UIManager;
 import javax.swing.border.AbstractBorder;
 import javax.swing.border.Border;
-import javax.swing.plaf.ComponentUI;
 import com.formdev.flatlaf.FlatClientProperties;
 import com.formdev.flatlaf.FlatSystemProperties;
 import com.formdev.flatlaf.ui.FlatNativeWindowBorder.WindowTopBorder;
@@ -1145,77 +1143,7 @@ private boolean captionHitTest( Point pt ) {
 	}
 
 	private boolean isTitleBarCaptionAt( Component c, int x, int y ) {
-		if( !c.isDisplayable() || !c.isVisible() || !contains( c, x, y ) || c == mouseLayer )
-			return true; // continue checking with next component
-
-		// check enabled component that has mouse listeners
-		if( c.isEnabled() &&
-			(c.getMouseListeners().length > 0 ||
-			 c.getMouseMotionListeners().length > 0) )
-		{
-			if( !(c instanceof JComponent) )
-				return false; // assume that this is not a caption because the component has mouse listeners
-
-			// check client property boolean value
-			Object caption = ((JComponent)c).getClientProperty( COMPONENT_TITLE_BAR_CAPTION );
-			if( caption instanceof Boolean )
-				return (boolean) caption;
-
-			// if component is not fully layouted, do not invoke function
-			// because it is too dangerous that the function tries to layout the component,
-			// which could cause a dead lock
-			if( !c.isValid() ) {
-				// revalidate if necessary so that it is valid when invoked again later
-				EventQueue.invokeLater( () -> {
-					Window w = SwingUtilities.windowForComponent( c );
-					if( w != null )
-						w.revalidate();
-					else
-						c.revalidate();
-				} );
-
-				return false; // assume that this is not a caption because the component has mouse listeners
-			}
-
-			if( caption instanceof Function ) {
-				// check client property function value
-				@SuppressWarnings( "unchecked" )
-				Function<Point, Boolean> hitTest = (Function<Point, Boolean>) caption;
-				Boolean result = hitTest.apply( new Point( x, y ) );
-				if( result != null )
-					return result;
-			} else {
-				// check component UI
-				ComponentUI ui = JavaCompatibility2.getUI( (JComponent) c );
-				if( !(ui instanceof TitleBarCaptionHitTest) )
-					return false; // assume that this is not a caption because the component has mouse listeners
-
-				Boolean result = ((TitleBarCaptionHitTest)ui).isTitleBarCaptionAt( x, y );
-				if( result != null )
-					return result;
-			}
-
-			// else continue checking children
-		}
-
-		// check children
-		if( c instanceof Container ) {
-			for( Component child : ((Container)c).getComponents() ) {
-				if( !isTitleBarCaptionAt( child, x - child.getX(), y - child.getY() ) )
-					return false;
-			}
-		}
-		return true;
-	}
-
-	/**
-	 * Same as {@link Component#contains(int, int)}, but not using that method
-	 * because it may be overridden by custom components and invoke code that
-	 * tries to request AWT tree lock on 'AWT-Windows' thread.
-	 * This could freeze the application if AWT tree is already locked on 'AWT-EventQueue' thread.
-	 */
-	private boolean contains( Component c, int x, int y ) {
-		return x >= 0 && y >= 0 && x < c.getWidth() && y < c.getHeight();
+		return FullWindowContentSupport.isTitleBarCaptionAt( c, x, y, mouseLayer );
 	}
 
 	private int lastCaptionHitTestX;