Linux: use X11 window manager events to move window and to show window menu (right-click on window title bar), if custom window decorations are enabled (issue #482)

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

@@ -56,6 +56,10 @@ class FlatNativeLibrary
 
 			// load jawt native library
 			loadJAWT();
+		} else if( SystemInfo.isLinux && SystemInfo.isX86_64 ) {
+			// Linux: requires x86_64
+
+			libraryName = "flatlaf-linux-x86_64";
 		} else
 			return; // no native library available for current OS or CPU architecture
 

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

@@ -0,0 +1,104 @@
+/*
+ * Copyright 2022 FormDev Software GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.formdev.flatlaf.ui;
+
+import java.awt.Point;
+import java.awt.Toolkit;
+import java.awt.Window;
+import java.awt.event.MouseEvent;
+import java.awt.geom.AffineTransform;
+import javax.swing.JDialog;
+import javax.swing.JFrame;
+
+/**
+ * Native methods for Linux.
+ * <p>
+ * <b>Note</b>: This is private API. Do not use!
+ *
+ * @author Karl Tauber
+ * @since 2.5
+ */
+class FlatNativeLinuxLibrary
+{
+	static boolean isLoaded() {
+		return FlatNativeLibrary.isLoaded();
+	}
+
+	// direction for _NET_WM_MOVERESIZE message
+	// see https://specifications.freedesktop.org/wm-spec/wm-spec-latest.html
+	static final int MOVE = 8;
+
+	private static Boolean isXWindowSystem;
+
+	private static boolean isXWindowSystem() {
+		if( isXWindowSystem == null )
+			isXWindowSystem = Toolkit.getDefaultToolkit().getClass().getName().endsWith( ".XToolkit" );
+		return isXWindowSystem;
+	}
+
+	static boolean isWMUtilsSupported( Window window ) {
+		return hasCustomDecoration( window ) && isXWindowSystem() && isLoaded();
+	}
+
+	static boolean moveOrResizeWindow( Window window, MouseEvent e, int direction ) {
+		Point pt = scale( window, e.getLocationOnScreen() );
+		return xMoveOrResizeWindow( window, pt.x, pt.y, direction );
+
+/*
+		try {
+			Class<?> cls = Class.forName( "com.formdev.flatlaf.natives.jna.linux.X11WmUtils" );
+			java.lang.reflect.Method m = cls.getMethod( "xMoveOrResizeWindow", Window.class, int.class, int.class, int.class );
+			return (Boolean) m.invoke( null, window, pt.x, pt.y, direction );
+		} catch (Exception ex) {
+			ex.printStackTrace();
+			return false;
+		}
+*/
+	}
+
+	static boolean showWindowMenu( Window window, MouseEvent e ) {
+		Point pt = scale( window, e.getLocationOnScreen() );
+		return xShowWindowMenu( window, pt.x, pt.y );
+
+/*
+		try {
+			Class<?> cls = Class.forName( "com.formdev.flatlaf.natives.jna.linux.X11WmUtils" );
+			java.lang.reflect.Method m = cls.getMethod( "xShowWindowMenu", Window.class, int.class, int.class );
+			return (Boolean) m.invoke( null, window, pt.x, pt.y );
+		} catch (Exception ex) {
+			ex.printStackTrace();
+			return false;
+		}
+*/
+	}
+
+	private static Point scale( Window window, Point pt ) {
+		AffineTransform transform = window.getGraphicsConfiguration().getDefaultTransform();
+		int x = (int) Math.round( pt.x * transform.getScaleX() );
+		int y = (int) Math.round( pt.y * transform.getScaleY() );
+		return new Point( x, y );
+	}
+
+	// X Window System
+	private static native boolean xMoveOrResizeWindow( Window window, int x, int y, int direction );
+	private static native boolean xShowWindowMenu( Window window, int x, int y );
+
+	private static boolean hasCustomDecoration( Window window ) {
+		return (window instanceof JFrame && JFrame.isDefaultLookAndFeelDecorated() && ((JFrame)window).isUndecorated()) ||
+			(window instanceof JDialog && JDialog.isDefaultLookAndFeelDecorated() && ((JDialog)window).isUndecorated());
+	}
+}

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

@@ -357,6 +357,7 @@ public class FlatTitlePane
 			restoreButton.setVisible( resizable && maximized );
 
 			if( maximized &&
+				!(SystemInfo.isLinux && FlatNativeLinuxLibrary.isWMUtilsSupported( window )) &&
 				rootPane.getClientProperty( "_flatlaf.maximizedBoundsUpToDate" ) == null )
 			{
 				rootPane.putClientProperty( "_flatlaf.maximizedBoundsUpToDate", null );
@@ -737,6 +738,17 @@ debug*/
 		}
 	}
 
+	private void maximizeOrRestore() {
+		if( !(window instanceof Frame) || !((Frame)window).isResizable() )
+			return;
+
+		Frame frame = (Frame) window;
+		if( (frame.getExtendedState() & Frame.MAXIMIZED_BOTH) != 0 )
+			restore();
+		else
+			maximize();
+	}
+
 	/**
 	 * Closes the window.
 	 */
@@ -1154,23 +1166,23 @@ debug*/
 		//---- interface MouseListener ----
 
 		private Point dragOffset;
+		private boolean nativeMove;
 
 		@Override
 		public void mouseClicked( MouseEvent e ) {
+			// on Linux, when using native library, the mouse clicked event
+			// is usually not sent and maximize/restore is done in mouse pressed event
+			// this check is here for the case that a mouse clicked event comes thru for some reason
+			if( SystemInfo.isLinux && FlatNativeLinuxLibrary.isWMUtilsSupported( window ) )
+				return;
+
 			if( e.getClickCount() == 2 && SwingUtilities.isLeftMouseButton( e ) ) {
 				if( e.getSource() == iconLabel ) {
 					// double-click on icon closes window
 					close();
-				} else if( !hasNativeCustomDecoration() &&
-					window instanceof Frame &&
-					((Frame)window).isResizable() )
-				{
+				} else if( !hasNativeCustomDecoration() ) {
 					// maximize/restore on double-click
-					Frame frame = (Frame) window;
-					if( (frame.getExtendedState() & Frame.MAXIMIZED_BOTH) != 0 )
-						restore();
-					else
-						maximize();
+					maximizeOrRestore();
 				}
 			}
 		}
@@ -1180,10 +1192,37 @@ debug*/
 			if( window == null )
 				return; // should newer occur
 
+			// on Linux, show window menu
+			if( SwingUtilities.isRightMouseButton( e ) &&
+				SystemInfo.isLinux && FlatNativeLinuxLibrary.isWMUtilsSupported( window ) )
+			{
+				e.consume();
+				FlatNativeLinuxLibrary.showWindowMenu( window, e );
+				return;
+			}
+
 			if( !SwingUtilities.isLeftMouseButton( e ) )
 				return;
 
 			dragOffset = SwingUtilities.convertPoint( FlatTitlePane.this, e.getPoint(), window );
+			nativeMove = false;
+
+			// on Linux, move or maximize/restore window
+			if( SystemInfo.isLinux && FlatNativeLinuxLibrary.isWMUtilsSupported( window ) ) {
+				switch( e.getClickCount() ) {
+					case 1:
+						// move window via _NET_WM_MOVERESIZE event
+						e.consume();
+						nativeMove = FlatNativeLinuxLibrary.moveOrResizeWindow( window, e, FlatNativeLinuxLibrary.MOVE );
+						break;
+
+					case 2:
+						// maximize/restore on double-click
+						// also done here because no mouse clicked event is sent when using _NET_WM_MOVERESIZE event
+						maximizeOrRestore();
+						break;
+				}
+			}
 		}
 
 		@Override public void mouseReleased( MouseEvent e ) {}
@@ -1194,9 +1233,12 @@ debug*/
 
 		@Override
 		public void mouseDragged( MouseEvent e ) {
-			if( window == null )
+			if( window == null || dragOffset == null )
 				return; // should newer occur
 
+			if( nativeMove )
+				return;
+
 			if( !SwingUtilities.isLeftMouseButton( e ) )
 				return;
 

flatlaf-core/src/main/java/com/formdev/flatlaf/util/NativeLibrary.java

@@ -138,7 +138,7 @@ public class NativeLibrary
 			System.load( libraryFile.getAbsolutePath() );
 			return true;
 		} catch( Throwable ex ) {
-			log( null, ex );
+			log( ex.getMessage(), ex );
 			return false;
 		}
 	}