Styling: support cell borders of List and Table

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

@@ -61,8 +61,8 @@ public class FlatLineBorder
 		Graphics2D g2 = (Graphics2D) g.create();
 		try {
 			FlatUIUtils.setRenderingHints( g2 );
-			g2.setColor( lineColor );
+			g2.setColor( getLineColor() );
-			FlatUIUtils.paintComponentBorder( g2, x, y, width, height, 0f, scale( lineThickness ), 0f );
+			FlatUIUtils.paintComponentBorder( g2, x, y, width, height, 0f, scale( getLineThickness() ), 0f );
 		} finally {
 			g2.dispose();
 		}

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

@@ -16,11 +16,16 @@
 
 package com.formdev.flatlaf.ui;
 
+import static com.formdev.flatlaf.util.UIScale.scale;
+import java.awt.Color;
 import java.awt.Component;
 import java.awt.Graphics;
+import java.awt.Insets;
+import java.util.function.Function;
 import javax.swing.JList;
 import javax.swing.SwingUtilities;
 import javax.swing.UIManager;
+import javax.swing.plaf.ListUI;
 
 /**
  * Cell border for {@link javax.swing.DefaultListCellRenderer}
@@ -33,12 +38,59 @@ import javax.swing.UIManager;
 public class FlatListCellBorder
 	extends FlatLineBorder
 {
-	final boolean showCellFocusIndicator = UIManager.getBoolean( "List.showCellFocusIndicator" );
+	protected boolean showCellFocusIndicator = UIManager.getBoolean( "List.showCellFocusIndicator" );
+
+	private Component c;
 
 	protected FlatListCellBorder() {
 		super( UIManager.getInsets( "List.cellMargins" ), UIManager.getColor( "List.cellFocusColor" ) );
 	}
 
+	@Override
+	public Insets getBorderInsets( Component c, Insets insets ) {
+		Insets margins = getStyleFromListUI( c, ui -> ui.cellMargins );
+		if( margins != null ) {
+			boolean leftToRight = margins.left == margins.right || c.getComponentOrientation().isLeftToRight();
+			insets.left = scale( leftToRight ? margins.left : margins.right );
+			insets.top = scale( margins.top );
+			insets.right = scale( leftToRight ? margins.right : margins.left );
+			insets.bottom = scale( margins.bottom );
+			return insets;
+		}
+		return super.getBorderInsets( c, insets );
+	}
+
+	@Override
+	public Color getLineColor() {
+		if( c != null ) {
+			Color color = getStyleFromListUI( c, ui -> ui.cellFocusColor );
+			if( color != null )
+				return color;
+		}
+		return super.getLineColor();
+	}
+
+	@Override
+	public void paintBorder( Component c, Graphics g, int x, int y, int width, int height ) {
+		this.c = c;
+		super.paintBorder( c, g, x, y, width, height );
+		this.c = null;
+	}
+
+	/**
+	 * Because this borders are always shared for all lists,
+	 * get border specific style from FlatListUI.
+	 */
+	static <T> T getStyleFromListUI( Component c, Function<FlatListUI, T> f ) {
+		JList<?> list = (JList<?>) SwingUtilities.getAncestorOfClass( JList.class, c );
+		if( list != null ) {
+			ListUI ui = list.getUI();
+			if( ui instanceof FlatListUI )
+				return f.apply( (FlatListUI) ui );
+		}
+		return null;
+	}
+
 	//---- class Default ------------------------------------------------------
 
 	/**
@@ -74,6 +126,8 @@ public class FlatListCellBorder
 	{
 		@Override
 		public void paintBorder( Component c, Graphics g, int x, int y, int width, int height ) {
+			Boolean b = getStyleFromListUI( c, ui -> ui.showCellFocusIndicator );
+			boolean showCellFocusIndicator = (b != null) ? b : this.showCellFocusIndicator;
 			if( !showCellFocusIndicator )
 				return;
 

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

@@ -18,6 +18,7 @@ package com.formdev.flatlaf.ui;
 
 import java.awt.Color;
 import java.awt.EventQueue;
+import java.awt.Insets;
 import java.awt.event.FocusEvent;
 import java.awt.event.FocusListener;
 import java.beans.PropertyChangeListener;
@@ -72,6 +73,11 @@ public class FlatListUI
 	@Styleable protected Color selectionInactiveBackground;
 	@Styleable protected Color selectionInactiveForeground;
 
+	// for FlatListCellBorder
+	@Styleable protected Insets cellMargins;
+	@Styleable protected Color cellFocusColor;
+	@Styleable protected boolean showCellFocusIndicator;
+
 	private Map<String, Object> oldStyleValues;
 
 	public static ComponentUI createUI( JComponent c ) {

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

@@ -16,11 +16,16 @@
 
 package com.formdev.flatlaf.ui;
 
+import static com.formdev.flatlaf.util.UIScale.scale;
+import java.awt.Color;
 import java.awt.Component;
 import java.awt.Graphics;
+import java.awt.Insets;
+import java.util.function.Function;
 import javax.swing.JTable;
 import javax.swing.SwingUtilities;
 import javax.swing.UIManager;
+import javax.swing.plaf.TableUI;
 
 /**
  * Cell border for {@link javax.swing.table.DefaultTableCellRenderer}
@@ -33,12 +38,59 @@ import javax.swing.UIManager;
 public class FlatTableCellBorder
 	extends FlatLineBorder
 {
-	final boolean showCellFocusIndicator = UIManager.getBoolean( "Table.showCellFocusIndicator" );
+	protected boolean showCellFocusIndicator = UIManager.getBoolean( "Table.showCellFocusIndicator" );
+
+	private Component c;
 
 	protected FlatTableCellBorder() {
 		super( UIManager.getInsets( "Table.cellMargins" ), UIManager.getColor( "Table.cellFocusColor" ) );
 	}
 
+	@Override
+	public Insets getBorderInsets( Component c, Insets insets ) {
+		Insets margins = getStyleFromTableUI( c, ui -> ui.cellMargins );
+		if( margins != null ) {
+			boolean leftToRight = margins.left == margins.right || c.getComponentOrientation().isLeftToRight();
+			insets.left = scale( leftToRight ? margins.left : margins.right );
+			insets.top = scale( margins.top );
+			insets.right = scale( leftToRight ? margins.right : margins.left );
+			insets.bottom = scale( margins.bottom );
+			return insets;
+		}
+		return super.getBorderInsets( c, insets );
+	}
+
+	@Override
+	public Color getLineColor() {
+		if( c != null ) {
+			Color color = getStyleFromTableUI( c, ui -> ui.cellFocusColor );
+			if( color != null )
+				return color;
+		}
+		return super.getLineColor();
+	}
+
+	@Override
+	public void paintBorder( Component c, Graphics g, int x, int y, int width, int height ) {
+		this.c = c;
+		super.paintBorder( c, g, x, y, width, height );
+		this.c = null;
+	}
+
+	/**
+	 * Because this borders are always shared for all tables,
+	 * get border specific style from FlatTableUI.
+	 */
+	static <T> T getStyleFromTableUI( Component c, Function<FlatTableUI, T> f ) {
+		JTable table = (JTable) SwingUtilities.getAncestorOfClass( JTable.class, c );
+		if( table != null ) {
+			TableUI ui = table.getUI();
+			if( ui instanceof FlatTableUI )
+				return f.apply( (FlatTableUI) ui );
+		}
+		return null;
+	}
+
 	//---- class Default ------------------------------------------------------
 
 	/**
@@ -74,6 +126,9 @@ public class FlatTableCellBorder
 	{
 		@Override
 		public void paintBorder( Component c, Graphics g, int x, int y, int width, int height ) {
+			Boolean b = getStyleFromTableUI( c, ui -> ui.showCellFocusIndicator );
+			boolean showCellFocusIndicator = (b != null) ? b : this.showCellFocusIndicator;
+
 			if( !showCellFocusIndicator ) {
 				JTable table = (JTable) SwingUtilities.getAncestorOfClass( JTable.class, c );
 				if( table != null && !isSelectionEditable( table ) )

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

@@ -22,6 +22,7 @@ import java.awt.Dimension;
 import java.awt.EventQueue;
 import java.awt.Graphics;
 import java.awt.Graphics2D;
+import java.awt.Insets;
 import java.awt.event.FocusEvent;
 import java.awt.event.FocusListener;
 import java.awt.geom.Rectangle2D;
@@ -101,6 +102,11 @@ public class FlatTableUI
 	@Styleable protected Color selectionInactiveBackground;
 	@Styleable protected Color selectionInactiveForeground;
 
+	// for FlatTableCellBorder
+	@Styleable protected Insets cellMargins;
+	@Styleable protected Color cellFocusColor;
+	@Styleable protected boolean showCellFocusIndicator;
+
 	private boolean oldShowHorizontalLines;
 	private boolean oldShowVerticalLines;
 	private Dimension oldIntercellSpacing;

flatlaf-core/src/test/java/com/formdev/flatlaf/ui/FlatStylingTests.java

@@ -182,6 +182,11 @@ public class FlatStylingTests
 		ui.applyStyle( "selectionForeground: #fff" );
 		ui.applyStyle( "selectionInactiveBackground: #fff" );
 		ui.applyStyle( "selectionInactiveForeground: #fff" );
+
+		// FlatListCellBorder
+		ui.applyStyle( "cellMargins: 1,2,3,4" );
+		ui.applyStyle( "cellFocusColor: #fff" );
+		ui.applyStyle( "showCellFocusIndicator: true" );
 	}
 
 	@Test
@@ -481,6 +486,11 @@ public class FlatStylingTests
 		ui.applyStyle( "selectionForeground: #fff" );
 		ui.applyStyle( "selectionInactiveBackground: #fff" );
 		ui.applyStyle( "selectionInactiveForeground: #fff" );
+
+		// FlatTableCellBorder
+		ui.applyStyle( "cellMargins: 1,2,3,4" );
+		ui.applyStyle( "cellFocusColor: #fff" );
+		ui.applyStyle( "showCellFocusIndicator: true" );
 	}
 
 	@Test