Tree: use inactive selection background/foreground if tree is not focused

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

@@ -16,10 +16,18 @@
 
 package com.formdev.flatlaf.ui;
 
+import java.awt.Color;
+import java.awt.Component;
+import java.awt.Graphics;
+import java.awt.Insets;
+import java.awt.Rectangle;
 import javax.swing.JComponent;
 import javax.swing.LookAndFeel;
+import javax.swing.UIManager;
 import javax.swing.plaf.ComponentUI;
 import javax.swing.plaf.basic.BasicTreeUI;
+import javax.swing.tree.DefaultTreeCellRenderer;
+import javax.swing.tree.TreePath;
 import com.formdev.flatlaf.util.UIScale;
 
 /**
@@ -27,13 +35,22 @@ import com.formdev.flatlaf.util.UIScale;
  *
  * TODO document used UI defaults of superclass
  *
- * @uiDefault Tree.border						Border
+ * @uiDefault Tree.border							Border
+ * @uiDefault Tree.selectionBackground				Color
+ * @uiDefault Tree.selectionForeground				Color
+ * @uiDefault Tree.selectionInactiveBackground		Color
+ * @uiDefault Tree.selectionInactiveForeground		Color
  *
  * @author Karl Tauber
  */
 public class FlatTreeUI
 	extends BasicTreeUI
 {
+	protected Color selectionBackground;
+	protected Color selectionForeground;
+	protected Color selectionInactiveBackground;
+	protected Color selectionInactiveForeground;
+
 	public static ComponentUI createUI( JComponent c ) {
 		return new FlatTreeUI();
 	}
@@ -44,6 +61,11 @@ public class FlatTreeUI
 
 		LookAndFeel.installBorder( tree, "Tree.border" );
 
+		selectionBackground = UIManager.getColor( "Tree.selectionBackground" );
+		selectionForeground = UIManager.getColor( "Tree.selectionForeground" );
+		selectionInactiveBackground = UIManager.getColor( "Tree.selectionInactiveBackground" );
+		selectionInactiveForeground = UIManager.getColor( "Tree.selectionInactiveForeground" );
+
 		// scale
 		int rowHeight = FlatUIUtils.getUIInt( "Tree.rowHeight", 16 );
 		if( rowHeight > 0 )
@@ -57,5 +79,54 @@ public class FlatTreeUI
 		super.uninstallDefaults();
 
 		LookAndFeel.uninstallBorder( tree );
+
+		selectionBackground = null;
+		selectionForeground = null;
+		selectionInactiveBackground = null;
+		selectionInactiveForeground = null;
+	}
+
+	/**
+	 * Same as super.paintRow(), but uses inactive selection background/foreground if tree is not focused.
+	 */
+	@Override
+	protected void paintRow( Graphics g, Rectangle clipBounds, Insets insets, Rectangle bounds, TreePath path, int row,
+		boolean isExpanded, boolean hasBeenExpanded, boolean isLeaf )
+	{
+		if( editingComponent != null && editingRow == row )
+			return;
+
+		boolean hasFocus = tree.hasFocus();
+		boolean cellHasFocus = hasFocus && (row == getLeadSelectionRow());
+		boolean isSelected = tree.isRowSelected( row );
+
+		// get renderer component
+		Component rendererComponent = currentCellRenderer.getTreeCellRendererComponent( tree,
+			path.getLastPathComponent(), isSelected, isExpanded, isLeaf, row, cellHasFocus );
+
+		// apply inactive selection background/foreground if tree is not focused
+		Color oldBackgroundSelectionColor = null;
+		if( isSelected && !hasFocus ) {
+			if( rendererComponent instanceof DefaultTreeCellRenderer ) {
+				DefaultTreeCellRenderer renderer = (DefaultTreeCellRenderer) rendererComponent;
+				if( renderer.getBackgroundSelectionColor() == selectionBackground ) {
+					oldBackgroundSelectionColor = renderer.getBackgroundSelectionColor();
+					renderer.setBackgroundSelectionColor( selectionInactiveBackground );
+				}
+			} else {
+				if( rendererComponent.getBackground() == selectionBackground )
+					rendererComponent.setBackground( selectionInactiveBackground );
+			}
+
+			if( rendererComponent.getForeground() == selectionForeground )
+				rendererComponent.setForeground( selectionInactiveForeground );
+		}
+
+		// paint renderer
+		rendererPane.paintComponent( g, rendererComponent, tree, bounds.x, bounds.y, bounds.width, bounds.height, true );
+
+		// restore background selection color
+		if( oldBackgroundSelectionColor != null )
+			((DefaultTreeCellRenderer)rendererComponent).setBackgroundSelectionColor( oldBackgroundSelectionColor );
 	}
 }

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

@@ -388,6 +388,8 @@ ToolTip.border=2,6,2,6,@@Component.borderColor
 #---- Tree ----
 
 Tree.border=1,1,1,1
+Tree.selectionInactiveBackground=@selectionInactiveBackground
+Tree.selectionInactiveForeground=@selectionInactiveForeground
 Tree.textBackground=@@Tree.background
 Tree.selectionBorderColor=@cellFocusColor
 Tree.rendererMargins=1,2,1,2