Slider: hover support

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

@@ -20,6 +20,7 @@ import java.awt.Color;
 import java.awt.Dimension;
 import java.awt.Graphics;
 import java.awt.Graphics2D;
+import java.awt.event.MouseListener;
 import java.awt.geom.Path2D;
 import java.awt.geom.RoundRectangle2D;
 import javax.swing.JComponent;
@@ -39,13 +40,14 @@ import com.formdev.flatlaf.util.UIScale;
  * @uiDefault Slider.trackColor				Color
  * @uiDefault Slider.thumbColor				Color
  * @uiDefault Slider.tickColor				Color
+ * @uiDefault Slider.focusedColor			Color
+ * @uiDefault Slider.hoverColor				Color	optional; defaults to Slider.focusedColor
  * @uiDefault Slider.trackWidth				int
  * @uiDefault Slider.thumbWidth				int
  * @uiDefault Slider.horizontalSize			Dimension	preferred horizontal size; height is ignored; computed slider height is used
  * @uiDefault Slider.verticalSize			Dimension	preferred vertical size; width is ignored; computed slider width is used
  * @uiDefault Slider.minimumHorizontalSize	Dimension	height is ignored; computed slider height is used
  * @uiDefault Slider.minimumVerticalSize	Dimension	width is ignored; computed slider width is used
- * @uiDefault Component.focusColor			Color
  *
  * @author Karl Tauber
  */
@@ -57,8 +59,12 @@ public class FlatSliderUI
 
 	private Color trackColor;
 	private Color thumbColor;
-	private Color disabledForeground;
 	private Color focusColor;
+	private Color hoverColor;
+	private Color disabledForeground;
+
+	private MouseListener hoverListener;
+	private boolean hover;
 
 	public static ComponentUI createUI( JComponent c ) {
 		return new FlatSliderUI();
@@ -68,6 +74,24 @@ public class FlatSliderUI
 		super( null );
 	}
 
+	@Override
+	protected void installListeners( JSlider slider ) {
+		super.installListeners( slider );
+
+		hoverListener = new FlatUIUtils.HoverListener( slider, h -> {
+			hover = h;
+		} );
+		slider.addMouseListener( hoverListener );
+	}
+
+	@Override
+	protected void uninstallListeners( JSlider slider ) {
+		super.uninstallListeners( slider );
+
+		slider.removeMouseListener( hoverListener );
+		hoverListener = null;
+	}
+
 	@Override
 	protected void installDefaults( JSlider slider ) {
 		super.installDefaults( slider );
@@ -77,8 +101,9 @@ public class FlatSliderUI
 
 		trackColor = UIManager.getColor( "Slider.trackColor" );
 		thumbColor = UIManager.getColor( "Slider.thumbColor" );
+		focusColor = UIManager.getColor( "Slider.focusedColor" );
+		hoverColor = FlatUIUtils.getUIColor( "Slider.hoverColor", focusColor );
 		disabledForeground = UIManager.getColor( "Slider.disabledForeground" );
-		focusColor = UIManager.getColor( "Component.focusColor" );
 	}
 
 	@Override
@@ -87,8 +112,9 @@ public class FlatSliderUI
 
 		trackColor = null;
 		thumbColor = null;
-		disabledForeground = null;
 		focusColor = null;
+		hoverColor = null;
+		disabledForeground = null;
 	}
 
 	@Override
@@ -160,7 +186,7 @@ public class FlatSliderUI
 		}
 
 		if( coloredTrack != null ) {
-			g.setColor( slider.hasFocus() ? focusColor : thumbColor );
+			g.setColor( hover ? hoverColor : (slider.hasFocus() ? focusColor : thumbColor) );
 			((Graphics2D)g).fill( coloredTrack );
 		}
 
@@ -170,7 +196,9 @@ public class FlatSliderUI
 
 	@Override
 	public void paintThumb( Graphics g ) {
-		g.setColor( slider.hasFocus() ? focusColor : (slider.isEnabled() ? thumbColor : disabledForeground) );
+		g.setColor( slider.isEnabled()
+			? (hover ? hoverColor : (slider.hasFocus() ? focusColor : thumbColor))
+			: disabledForeground );
 
 		if( isRoundThumb() )
 			g.fillOval( thumbRect.x, thumbRect.y, thumbRect.width, thumbRect.height );

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

@@ -23,8 +23,11 @@ import java.awt.Graphics2D;
 import java.awt.Insets;
 import java.awt.Rectangle;
 import java.awt.RenderingHints;
+import java.awt.event.MouseAdapter;
+import java.awt.event.MouseEvent;
 import java.awt.geom.Path2D;
 import java.awt.geom.RoundRectangle2D;
+import java.util.function.Consumer;
 import javax.swing.JComponent;
 import javax.swing.UIManager;
 import javax.swing.plaf.ColorUIResource;
@@ -53,6 +56,11 @@ public class FlatUIUtils
 		return (color != null) ? color : new Color( defaultColorRGB );
 	}
 
+	public static Color getUIColor( String key, Color defaultColor ) {
+		Color color = UIManager.getColor( key );
+		return (color != null) ? color : defaultColor;
+	}
+
 	public static int getUIInt( String key, int defaultValue ) {
 		Object value = UIManager.get( key );
 		return (value instanceof Integer) ? (Integer) value : defaultValue;
@@ -180,4 +188,35 @@ public class FlatUIUtils
 	{
 		JavaCompatibility.drawStringUnderlineCharAt( c, g, text, underlinedIndex, x, y );
 	}
+
+	//---- class HoverListener ------------------------------------------------
+
+	public static class HoverListener
+		extends MouseAdapter
+	{
+		private final JComponent repaintComponent;
+		private final Consumer<Boolean> hoverChanged;
+
+		public HoverListener( JComponent repaintComponent, Consumer<Boolean> hoverChanged ) {
+			this.repaintComponent = repaintComponent;
+			this.hoverChanged = hoverChanged;
+		}
+
+		@Override
+		public void mouseEntered( MouseEvent e ) {
+			hoverChanged.accept( true );
+			repaint();
+		}
+
+		@Override
+		public void mouseExited( MouseEvent e ) {
+			hoverChanged.accept( false );
+			repaint();
+		}
+
+		private void repaint() {
+			if( repaintComponent != null && repaintComponent.isEnabled() )
+				repaintComponent.repaint();
+		}
+	}
 }

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

@@ -169,6 +169,7 @@ Separator.foreground=515151
 Slider.trackColor=646464
 Slider.thumbColor=A6A6A6
 Slider.tickColor=888888
+Slider.focusedColor=@@Component.focusColor
 Slider.disabledForeground=4c5052
 
 

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

@@ -174,6 +174,7 @@ Separator.foreground=cdcdcd
 Slider.trackColor=c4c4c4
 Slider.thumbColor=6e6e6e
 Slider.tickColor=888888
+Slider.focusedColor=@@Component.focusColor
 Slider.disabledForeground=c0c0c0
 
 

flatlaf-core/src/test/resources/com/formdev/flatlaf/FlatTestLaf.properties

@@ -180,6 +180,8 @@ Separator.stripeIndent=5
 Slider.trackColor=00bb00
 Slider.thumbColor=880000
 Slider.tickColor=ff0000
+Slider.focusedColor=@@Component.focusColor
+Slider.hoverColor=0000ff
 Slider.disabledForeground=000088