List: rounded selection

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

@@ -17,20 +17,33 @@
 package com.formdev.flatlaf.ui;
 
 import java.awt.Color;
+import java.awt.Component;
 import java.awt.EventQueue;
+import java.awt.Graphics;
+import java.awt.Graphics2D;
 import java.awt.Insets;
+import java.awt.Point;
+import java.awt.Rectangle;
 import java.awt.event.FocusEvent;
 import java.awt.event.FocusListener;
 import java.beans.PropertyChangeListener;
 import java.util.Map;
+import javax.swing.DefaultListCellRenderer;
 import javax.swing.JComponent;
+import javax.swing.JList;
+import javax.swing.ListCellRenderer;
+import javax.swing.ListModel;
+import javax.swing.ListSelectionModel;
 import javax.swing.UIManager;
+import javax.swing.event.ListSelectionListener;
 import javax.swing.plaf.ComponentUI;
 import javax.swing.plaf.basic.BasicListUI;
 import com.formdev.flatlaf.FlatClientProperties;
 import com.formdev.flatlaf.ui.FlatStylingSupport.Styleable;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableUI;
+import com.formdev.flatlaf.util.Graphics2DProxy;
 import com.formdev.flatlaf.util.LoggingFacade;
+import com.formdev.flatlaf.util.UIScale;
 
 /**
  * Provides the Flat LaF UI delegate for {@link javax.swing.JList}.
@@ -59,6 +72,8 @@
  *
  * @uiDefault List.selectionInactiveBackground		Color
  * @uiDefault List.selectionInactiveForeground		Color
+ * @uiDefault List.selectionInsets					Insets
+ * @uiDefault List.selectionArc						int
  *
  * <!-- FlatListCellBorder -->
  *
@@ -76,6 +91,8 @@ public class FlatListUI
 	@Styleable protected Color selectionForeground;
 	@Styleable protected Color selectionInactiveBackground;
 	@Styleable protected Color selectionInactiveForeground;
+	/** @since 3 */ @Styleable protected Insets selectionInsets;
+	/** @since 3 */ @Styleable protected int selectionArc;
 
 	// for FlatListCellBorder
 	/** @since 2 */ @Styleable protected Insets cellMargins;
@@ -103,6 +120,8 @@ protected void installDefaults() {
 		selectionForeground = UIManager.getColor( "List.selectionForeground" );
 		selectionInactiveBackground = UIManager.getColor( "List.selectionInactiveBackground" );
 		selectionInactiveForeground = UIManager.getColor( "List.selectionInactiveForeground" );
+		selectionInsets = UIManager.getInsets( "List.selectionInsets" );
+		selectionArc = UIManager.getInt( "List.selectionArc" );
 
 		toggleSelectionColors();
 	}
@@ -161,6 +180,29 @@ protected PropertyChangeListener createPropertyChangeListener() {
 		};
 	}
 
+	@Override
+	protected ListSelectionListener createListSelectionListener() {
+		ListSelectionListener superListener = super.createListSelectionListener();
+		return e -> {
+			superListener.valueChanged( e );
+
+			// for united rounded selection, repaint parts of the rows/columns that adjoin to the changed rows/columns
+			if( useUnitedRoundedSelection( true, true ) &&
+				!list.isSelectionEmpty() &&
+				(list.getMaxSelectionIndex() - list.getMinSelectionIndex()) >= 1 )
+			{
+				int size = list.getModel().getSize();
+				int firstIndex = Math.min( Math.max( e.getFirstIndex(), 0 ), size - 1 );
+				int lastIndex = Math.min( Math.max( e.getLastIndex(), 0 ), size - 1 );
+				Rectangle r = getCellBounds( list, firstIndex, lastIndex );
+				if( r != null ) {
+					int arc = (int) Math.ceil( UIScale.scale( selectionArc / 2f ) );
+					list.repaint( r.x - arc, r.y - arc, r.width + (arc * 2), r.height + (arc * 2) );
+				}
+			}
+		};
+	}
+
 	/** @since 2 */
 	protected void installStyle() {
 		try {
@@ -234,4 +276,163 @@ private void toggleSelectionColors() {
 				list.setSelectionForeground( selectionInactiveForeground );
 		}
 	}
+
+	@SuppressWarnings( "rawtypes" )
+	@Override
+	protected void paintCell( Graphics g, int row, Rectangle rowBounds, ListCellRenderer cellRenderer,
+		ListModel dataModel, ListSelectionModel selModel, int leadIndex )
+	{
+		boolean isSelected = selModel.isSelectedIndex( row );
+
+		// get renderer component
+		@SuppressWarnings( "unchecked" )
+		Component rendererComponent = cellRenderer.getListCellRendererComponent( list,
+			dataModel.getElementAt( row ), row, isSelected, list.hasFocus() && (row == leadIndex) );
+
+		//
+		boolean isFileList = Boolean.TRUE.equals( list.getClientProperty( "List.isFileList" ) );
+		int cx, cw;
+		if( isFileList ) {
+			// see BasicListUI.paintCell()
+			cw = Math.min( rowBounds.width, rendererComponent.getPreferredSize().width + 4 );
+			cx = list.getComponentOrientation().isLeftToRight()
+				? rowBounds.x
+				: rowBounds.x + (rowBounds.width - cw);
+		} else {
+			cx = rowBounds.x;
+			cw = rowBounds.width;
+		}
+
+		// rounded selection or selection insets
+		if( isSelected &&
+			!isFileList && // rounded selection is not supported for file list
+			rendererComponent instanceof DefaultListCellRenderer &&
+			(selectionArc > 0 ||
+			 (selectionInsets != null &&
+			  (selectionInsets.top != 0 || selectionInsets.left != 0 || selectionInsets.bottom != 0 || selectionInsets.right != 0))) )
+		{
+			// Because selection painting is done in the cell renderer, it would be
+			// necessary to require a FlatLaf specific renderer to implement rounded selection.
+			// Using a LaF specific renderer was avoided because often a custom renderer is
+			// already used in applications. Then either the rounded selection is not used,
+			// or the application has to be changed to extend a FlatLaf renderer.
+			//
+			// To solve this, a graphics proxy is used that paints rounded selection
+			// if row is selected and the renderer wants to fill the background.
+			class RoundedSelectionGraphics extends Graphics2DProxy {
+				// used to avoid endless loop in case that paintCellSelection() invokes
+				// g.fillRect() with full bounds (selectionInsets is 0,0,0,0)
+				private boolean inPaintSelection;
+
+				RoundedSelectionGraphics( Graphics delegate ) {
+					super( (Graphics2D) delegate );
+				}
+
+				@Override
+				public Graphics create() {
+					return new RoundedSelectionGraphics( super.create() );
+				}
+
+				@Override
+				public Graphics create( int x, int y, int width, int height ) {
+					return new RoundedSelectionGraphics( super.create( x, y, width, height ) );
+				}
+
+				@Override
+				public void fillRect( int x, int y, int width, int height ) {
+					if( !inPaintSelection &&
+						x == 0 && y == 0 && width == rowBounds.width && height == rowBounds.height &&
+						this.getColor() == rendererComponent.getBackground() )
+					{
+						inPaintSelection = true;
+						paintCellSelection( this, row, x, y, width, height );
+						inPaintSelection = false;
+					} else
+						super.fillRect( x, y, width, height );
+				}
+			}
+			g = new RoundedSelectionGraphics( g );
+		}
+
+		// paint renderer
+		rendererPane.paintComponent( g, rendererComponent, list, cx, rowBounds.y, cw, rowBounds.height, true );
+	}
+
+	/** @since 3 */
+	protected void paintCellSelection( Graphics g, int row, int x, int y, int width, int height ) {
+		float arcTopLeft, arcTopRight, arcBottomLeft, arcBottomRight;
+		arcTopLeft = arcTopRight = arcBottomLeft = arcBottomRight = UIScale.scale( selectionArc / 2f );
+
+		if( list.getLayoutOrientation() == JList.VERTICAL ) {
+			// layout orientation: VERTICAL
+			if( useUnitedRoundedSelection( true, false ) ) {
+				if( row > 0 && list.isSelectedIndex( row - 1 ) )
+					arcTopLeft = arcTopRight = 0;
+				if( row < list.getModel().getSize() - 1 && list.isSelectedIndex( row + 1 ) )
+					arcBottomLeft = arcBottomRight = 0;
+			}
+		} else {
+			// layout orientation: VERTICAL_WRAP or HORIZONTAL_WRAP
+			Rectangle r = null;
+			if( useUnitedRoundedSelection( true, false ) ) {
+				// vertical: check whether cells above or below are selected
+				r = getCellBounds( list, row, row );
+
+				int topIndex = locationToIndex( list, new Point( r.x, r.y - 1 ) );
+				int bottomIndex = locationToIndex( list, new Point( r.x, r.y + r.height ) );
+
+				if( topIndex >= 0 && topIndex != row && list.isSelectedIndex( topIndex ) )
+					arcTopLeft = arcTopRight = 0;
+				if( bottomIndex >= 0 && bottomIndex != row && list.isSelectedIndex( bottomIndex ) )
+					arcBottomLeft = arcBottomRight = 0;
+			}
+
+			if( useUnitedRoundedSelection( false, true ) ) {
+				// horizontal: check whether cells left or right are selected
+				if( r == null )
+					r = getCellBounds( list, row, row );
+
+				int leftIndex = locationToIndex( list, new Point( r.x - 1, r.y ) );
+				int rightIndex = locationToIndex( list, new Point( r.x + r.width, r.y ) );
+
+				// special handling for the case that last column contains less cells than the other columns
+				boolean ltr = list.getComponentOrientation().isLeftToRight();
+				if( !ltr && leftIndex >= 0 && leftIndex != row && leftIndex == locationToIndex( list, new Point( r.x - 1, r.y - 1 ) ) )
+					leftIndex = -1;
+				if( ltr && rightIndex >= 0 && rightIndex != row && rightIndex == locationToIndex( list, new Point( r.x + r.width, r.y - 1 ) ) )
+					rightIndex = -1;
+
+				if( leftIndex >= 0 && leftIndex != row && list.isSelectedIndex( leftIndex ) )
+					arcTopLeft = arcBottomLeft = 0;
+				if( rightIndex >= 0 && rightIndex != row && list.isSelectedIndex( rightIndex ) )
+					arcTopRight = arcBottomRight = 0;
+			}
+		}
+
+		FlatUIUtils.paintSelection( (Graphics2D) g, x, y, width, height,
+			UIScale.scale( selectionInsets ), arcTopLeft, arcTopRight, arcBottomLeft, arcBottomRight, 0 );
+	}
+
+	private boolean useUnitedRoundedSelection( boolean vertical, boolean horizontal ) {
+		return selectionArc > 0 &&
+			(selectionInsets == null ||
+			 (vertical && selectionInsets.top == 0 && selectionInsets.bottom == 0) ||
+			 (horizontal && selectionInsets.left == 0 && selectionInsets.right == 0));
+	}
+
+	/**
+	 * Paints a cell selection at the given coordinates.
+	 * The selection color must be set on the graphics context.
+	 * <p>
+	 * This method is intended for use in custom cell renderers.
+	 *
+	 * @since 3
+	 */
+	public static void paintCellSelection( JList<?> list, Graphics g, int row, int x, int y, int width, int height ) {
+		if( !(list.getUI() instanceof FlatListUI) )
+			return;
+
+		FlatListUI ui = (FlatListUI) list.getUI();
+		ui.paintCellSelection( g, row, x, y, width, height );
+	}
 }

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

@@ -318,12 +318,12 @@ protected TreeSelectionListener createTreeSelectionListener() {
 					// same is done in BasicTreeUI.Handler.valueChanged()
 					tree.repaint();
 				} else {
-					int arcHeight = (int) Math.ceil( UIScale.scale( (float) selectionArc ) );
+					int arc = (int) Math.ceil( UIScale.scale( selectionArc / 2f ) );
 
 					for( TreePath path : changedPaths ) {
 						Rectangle r = getPathBounds( tree, path );
 						if( r != null )
-							tree.repaint( r.x, r.y - arcHeight, r.width, r.height + (arcHeight * 2) );
+							tree.repaint( r.x, r.y - arc, r.width, r.height + (arc * 2) );
 					}
 				}
 			}

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

@@ -390,6 +390,8 @@ InternalFrameTitlePane.border = 0,8,0,0
 
 List.border = 0,0,0,0
 List.cellMargins = 1,6,1,6
+List.selectionInsets = 0,0,0,0
+List.selectionArc = 0
 List.cellFocusColor = @cellFocusColor
 List.cellNoFocusBorder = com.formdev.flatlaf.ui.FlatListCellBorder$Default
 List.focusCellHighlightBorder = com.formdev.flatlaf.ui.FlatListCellBorder$Focused
@@ -904,7 +906,6 @@ Tree.icon.closedColor = @icon
 Tree.icon.openColor = @icon
 
 
-
 #---- Styles ------------------------------------------------------------------
 
 #---- inTextField ----

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

@@ -254,6 +254,8 @@ void list() {
 			"selectionForeground", Color.class,
 			"selectionInactiveBackground", Color.class,
 			"selectionInactiveForeground", Color.class,
+			"selectionInsets", Insets.class,
+			"selectionArc", int.class,
 
 			// FlatListCellBorder
 			"cellMargins", Insets.class,

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

@@ -401,6 +401,8 @@ void list() {
 		ui.applyStyle( "selectionForeground: #fff" );
 		ui.applyStyle( "selectionInactiveBackground: #fff" );
 		ui.applyStyle( "selectionInactiveForeground: #fff" );
+		ui.applyStyle( "selectionInsets: 1,2,3,4" );
+		ui.applyStyle( "selectionArc: 8" );
 
 		// FlatListCellBorder
 		ui.applyStyle( "cellMargins: 1,2,3,4" );

flatlaf-demo/src/main/java/com/formdev/flatlaf/demo/intellijthemes/IJThemesPanel.java

@@ -19,6 +19,7 @@
 import java.awt.Component;
 import java.awt.Desktop;
 import java.awt.EventQueue;
+import java.awt.Graphics;
 import java.awt.Rectangle;
 import java.awt.Window;
 import java.awt.event.WindowAdapter;
@@ -40,6 +41,7 @@
 import java.util.Objects;
 import java.util.function.Predicate;
 import javax.swing.*;
+import javax.swing.border.Border;
 import javax.swing.border.CompoundBorder;
 import javax.swing.event.*;
 import com.formdev.flatlaf.FlatDarculaLaf;
@@ -52,6 +54,7 @@
 import com.formdev.flatlaf.demo.DemoPrefs;
 import com.formdev.flatlaf.extras.FlatAnimatedLafChange;
 import com.formdev.flatlaf.extras.FlatSVGIcon;
+import com.formdev.flatlaf.ui.FlatListUI;
 import com.formdev.flatlaf.util.LoggingFacade;
 import com.formdev.flatlaf.util.StringUtils;
 import net.miginfocom.swing.*;
@@ -89,10 +92,18 @@ public IJThemesPanel() {
 
 		// create renderer
 		themesList.setCellRenderer( new DefaultListCellRenderer() {
+			private int index;
+			private boolean isSelected;
+			private int titleHeight;
+
 			@Override
 			public Component getListCellRendererComponent( JList<?> list, Object value,
 				int index, boolean isSelected, boolean cellHasFocus )
 			{
+				this.index = index;
+				this.isSelected = isSelected;
+				this.titleHeight = 0;
+
 				String title = categories.get( index );
 				String name = ((IJThemeInfo)value).name;
 				int sep = name.indexOf( '/' );
@@ -101,11 +112,33 @@ public Component getListCellRendererComponent( JList<?> list, Object value,
 
 				JComponent c = (JComponent) super.getListCellRendererComponent( list, name, index, isSelected, cellHasFocus );
 				c.setToolTipText( buildToolTip( (IJThemeInfo) value ) );
-				if( title != null )
-					c.setBorder( new CompoundBorder( new ListCellTitledBorder( themesList, title ), c.getBorder() ) );
+				if( title != null ) {
+					Border titledBorder = new ListCellTitledBorder( themesList, title );
+					c.setBorder( new CompoundBorder( titledBorder, c.getBorder() ) );
+					titleHeight = titledBorder.getBorderInsets( c ).top;
+				}
 				return c;
 			}
 
+			@Override
+			public boolean isOpaque() {
+				return !isSelectedTitle();
+			}
+
+			@Override
+			protected void paintComponent( Graphics g ) {
+				if( isSelectedTitle() ) {
+					g.setColor( getBackground() );
+					FlatListUI.paintCellSelection( themesList, g, index, 0, titleHeight, getWidth(), getHeight() - titleHeight );
+				}
+
+				super.paintComponent( g );
+			}
+
+			private boolean isSelectedTitle() {
+				return titleHeight > 0 && isSelected && UIManager.getLookAndFeel() instanceof FlatLaf;
+			}
+
 			private String buildToolTip( IJThemeInfo ti ) {
 				if( ti.themeFile != null )
 					return ti.themeFile.getPath();

flatlaf-testing/dumps/uidefaults/FlatDarkLaf_1.8.0.txt

@@ -545,10 +545,12 @@ List.focusSelectedCellHighlightBorder [lazy] 1,6,1,6  false    com.formdev.flatl
 List.font                      [active] $defaultFont [UI]
 List.foreground                #bbbbbb  HSL   0   0  73    javax.swing.plaf.ColorUIResource [UI]
 List.noFocusBorder             1,1,1,1  false    javax.swing.plaf.BorderUIResource$EmptyBorderUIResource [UI]
+List.selectionArc              0
 List.selectionBackground       #4b6eaf  HSL 219  40  49    javax.swing.plaf.ColorUIResource [UI]
 List.selectionForeground       #bbbbbb  HSL   0   0  73    javax.swing.plaf.ColorUIResource [UI]
 List.selectionInactiveBackground #0f2a3d  HSL 205  61  15    javax.swing.plaf.ColorUIResource [UI]
 List.selectionInactiveForeground #bbbbbb  HSL   0   0  73    javax.swing.plaf.ColorUIResource [UI]
+List.selectionInsets           0,0,0,0    javax.swing.plaf.InsetsUIResource [UI]
 List.showCellFocusIndicator    false
 List.timeFactor                1000
 ListUI                         com.formdev.flatlaf.ui.FlatListUI