support painting separator line between window title and content (issue

#184)

CHANGELOG.md

@@ -3,6 +3,12 @@ FlatLaf Change Log
 
 ## 0.44-SNAPSHOT
 
+#### New features and improvements
+
+- Support painting separator line between window title and content (use UI value
+  `TitlePane.borderColor`). (issue #184)
+
+
 #### Fixed bugs
 
 - Custom window decorations: Not visible menu bar is now ignored in layout.

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

@@ -20,9 +20,7 @@
 import java.awt.Color;
 import java.awt.Component;
 import java.awt.Graphics;
-import java.awt.Graphics2D;
 import java.awt.Insets;
-import java.awt.geom.Rectangle2D;
 import javax.swing.JMenuBar;
 import javax.swing.UIManager;
 
@@ -40,16 +38,8 @@ public class FlatMenuBarBorder
 
 	@Override
 	public void paintBorder( Component c, Graphics g, int x, int y, int width, int height ) {
-		Graphics2D g2 = (Graphics2D) g.create();
-		try {
-			float lineHeight = scale( (float) 1 );
-
-			FlatUIUtils.setRenderingHints( g2 );
-			g2.setColor( borderColor );
-			g2.fill( new Rectangle2D.Float( x, y + height - lineHeight, width, lineHeight ) );
-		} finally {
-			g2.dispose();
-		}
+		float lineHeight = scale( (float) 1 );
+		FlatUIUtils.paintFilledRectangle( g, borderColor, x, y + height - lineHeight, width, lineHeight );
 	}
 
 	@Override

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

@@ -37,6 +37,7 @@
 import javax.swing.JRootPane;
 import javax.swing.LookAndFeel;
 import javax.swing.UIManager;
+import javax.swing.border.Border;
 import javax.swing.plaf.BorderUIResource;
 import javax.swing.plaf.ComponentUI;
 import javax.swing.plaf.UIResource;
@@ -45,6 +46,7 @@
 import com.formdev.flatlaf.FlatLaf;
 import com.formdev.flatlaf.util.HiDPIUtils;
 import com.formdev.flatlaf.util.SystemInfo;
+import com.formdev.flatlaf.util.UIScale;
 
 /**
  * Provides the Flat LaF UI delegate for {@link javax.swing.JRootPane}.
@@ -54,6 +56,7 @@
  * @uiDefault RootPane.border								Border
  * @uiDefault RootPane.activeBorderColor					Color
  * @uiDefault RootPane.inactiveBorderColor					Color
+ * @uiDefault TitlePane.borderColor							Color	optional
  *
  * <!-- FlatWindowResizer -->
  *
@@ -71,6 +74,8 @@ public class FlatRootPaneUI
 	static final boolean canUseJBRCustomDecorations
 		= SystemInfo.isJetBrainsJVM_11_orLater && SystemInfo.isWindows_10_orLater;
 
+	protected final Color borderColor = UIManager.getColor( "TitlePane.borderColor" );
+
 	protected JRootPane rootPane;
 	protected FlatTitlePane titlePane;
 	protected FlatWindowResizer windowResizer;
@@ -89,11 +94,21 @@ public void installUI( JComponent c ) {
 
 		if( rootPane.getWindowDecorationStyle() != JRootPane.NONE )
 			installClientDecorations();
+		else
+			installBorder();
 
 		if( canUseJBRCustomDecorations )
 			JBRCustomDecorations.install( rootPane );
 	}
 
+	protected void installBorder() {
+		if( borderColor != null ) {
+			Border b = rootPane.getBorder();
+			if( b == null || b instanceof UIResource )
+				rootPane.setBorder( new FlatWindowTitleBorder( borderColor ) );
+		}
+	}
+
 	@Override
 	public void uninstallUI( JComponent c ) {
 		super.uninstallUI( c );
@@ -119,11 +134,8 @@ protected void installDefaults( JRootPane c ) {
 		}
 
 		// enable dark window appearance on macOS when running in JetBrains Runtime
-		if( SystemInfo.isJetBrainsJVM && SystemInfo.isMacOS_10_14_Mojave_orLater ) {
-			LookAndFeel laf = UIManager.getLookAndFeel();
-			boolean isDark = laf instanceof FlatLaf && ((FlatLaf)laf).isDark();
-			c.putClientProperty( "jetbrains.awt.windowDarkAppearance", isDark );
-		}
+		if( SystemInfo.isJetBrainsJVM && SystemInfo.isMacOS_10_14_Mojave_orLater )
+			c.putClientProperty( "jetbrains.awt.windowDarkAppearance", FlatLaf.isLafDark() );
 	}
 
 	protected void installClientDecorations() {
@@ -203,6 +215,8 @@ public void propertyChange( PropertyChangeEvent e ) {
 				uninstallClientDecorations();
 				if( rootPane.getWindowDecorationStyle() != JRootPane.NONE )
 					installClientDecorations();
+				else
+					installBorder();
 				break;
 
 			case FlatClientProperties.MENU_BAR_EMBEDDED:
@@ -373,4 +387,40 @@ protected boolean isWindowMaximized( Component c ) {
 				: false;
 		}
 	}
+
+	//---- class FlatWindowTitleBorder ----------------------------------------
+
+	private static class FlatWindowTitleBorder
+		extends BorderUIResource.EmptyBorderUIResource
+	{
+		private final Color borderColor;
+
+		FlatWindowTitleBorder( Color borderColor ) {
+			super( 0, 0, 0, 0 );
+			this.borderColor = borderColor;
+		}
+
+		@Override
+		public void paintBorder( Component c, Graphics g, int x, int y, int width, int height ) {
+			if( showBorder( c ) ) {
+				float lineHeight = UIScale.scale( (float) 1 );
+				FlatUIUtils.paintFilledRectangle( g, borderColor, x, y, width, lineHeight );
+			}
+		}
+
+		@Override
+		public Insets getBorderInsets( Component c, Insets insets ) {
+			insets.set( showBorder( c ) ? 1 : 0, 0, 0, 0 );
+			return insets;
+		}
+
+		private boolean showBorder( Component c ) {
+			Container parent = c.getParent();
+			return
+				(parent instanceof JFrame &&
+				 (((JFrame)parent).getJMenuBar() == null ||
+				  !((JFrame)parent).getJMenuBar().isVisible())) ||
+				parent instanceof JDialog;
+		}
+	}
 }

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

@@ -76,6 +76,7 @@
  * @uiDefault TitlePane.foreground							Color
  * @uiDefault TitlePane.inactiveForeground					Color
  * @uiDefault TitlePane.embeddedForeground					Color
+ * @uiDefault TitlePane.borderColor							Color	optional
  * @uiDefault TitlePane.iconSize							Dimension
  * @uiDefault TitlePane.iconMargins							Insets
  * @uiDefault TitlePane.titleMargins						Insets
@@ -97,6 +98,7 @@ public class FlatTitlePane
 	protected final Color activeForeground = UIManager.getColor( "TitlePane.foreground" );
 	protected final Color inactiveForeground = UIManager.getColor( "TitlePane.inactiveForeground" );
 	protected final Color embeddedForeground = UIManager.getColor( "TitlePane.embeddedForeground" );
+	protected final Color borderColor = UIManager.getColor( "TitlePane.borderColor" );
 
 	protected final Insets menuBarMargins = UIManager.getInsets( "TitlePane.menuBarMargins" );
 	protected final Dimension iconSize = UIManager.getDimension( "TitlePane.iconSize" );
@@ -422,6 +424,10 @@ protected Insets getMenuBarMargins() {
 	protected void menuBarChanged() {
 		menuBarPlaceholder.invalidate();
 
+		// necessary for the case that an embedded menu bar is made invisible
+		// and a border color is specified
+		repaint();
+
 		// update title foreground color
 		EventQueue.invokeLater( () -> {
 			activeChanged( window == null || window.isActive() );
@@ -662,12 +668,13 @@ protected class FlatTitlePaneBorder
 		public Insets getBorderInsets( Component c, Insets insets ) {
 			super.getBorderInsets( c, insets );
 
-			// if menu bar is embedded, add bottom insets of menu bar border
 			Border menuBarBorder = getMenuBarBorder();
 			if( menuBarBorder != null ) {
+				// if menu bar is embedded, add bottom insets of menu bar border
 				Insets menuBarInsets = menuBarBorder.getBorderInsets( c );
 				insets.bottom += menuBarInsets.bottom;
-			}
+			} else if( borderColor != null && (rootPane.getJMenuBar() == null || !rootPane.getJMenuBar().isVisible()) )
+				insets.bottom += UIScale.scale( 1 );
 
 			if( hasJBRCustomDecoration() )
 				insets = FlatUIUtils.addInsets( insets, JBRWindowTopBorder.getInstance().getBorderInsets() );
@@ -677,10 +684,16 @@ public Insets getBorderInsets( Component c, Insets insets ) {
 
 		@Override
 		public void paintBorder( Component c, Graphics g, int x, int y, int width, int height ) {
-			// if menu bar is embedded, paint menu bar border
+			// paint bottom border
 			Border menuBarBorder = getMenuBarBorder();
-			if( menuBarBorder != null )
+			if( menuBarBorder != null ) {
+				// if menu bar is embedded, paint menu bar border
 				menuBarBorder.paintBorder( c, g, x, y, width, height );
+			} else if( borderColor != null && (rootPane.getJMenuBar() == null || !rootPane.getJMenuBar().isVisible()) ) {
+				// paint border between title pane and content if border color is specified
+				float lineHeight = UIScale.scale( (float) 1 );
+				FlatUIUtils.paintFilledRectangle( g, borderColor, x, y + height - lineHeight, width, lineHeight );
+			}
 
 			if( hasJBRCustomDecoration() )
 				JBRWindowTopBorder.getInstance().paintBorder( c, g, x, y, width, height );

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

@@ -379,6 +379,17 @@ public static Shape createComponentRectangle( float x, float y, float w, float h
 		return new RoundRectangle2D.Float( x, y, w, h, arc, arc );
 	}
 
+	static void paintFilledRectangle( Graphics g, Color color, float x, float y, float w, float h ) {
+		Graphics2D g2 = (Graphics2D) g.create();
+		try {
+			FlatUIUtils.setRenderingHints( g2 );
+			g2.setColor( color );
+			g2.fill( new Rectangle2D.Float( x, y, w, h ) );
+		} finally {
+			g2.dispose();
+		}
+	}
+
 	/**
 	 * Fill background with parent's background color because the visible component
 	 * is smaller than its bounds (for the focus decoration).