Slider: support per component custom thumb and track colors

CHANGELOG.md

@@ -11,6 +11,8 @@ FlatLaf Change Log
   UIManager.put("Button.defaultButtonFollowsFocus",true);`.
 - ComboBox, Spinner and SplitPaneDivider: Added pressed feedback to arrow
   buttons.
+- Slider: Support per component custom thumb and track colors via
+  `JSlider.setForeground(Color)` and `JSlider.setBackground(Color)`.
 - TextComponent: Clip placeholder text if it does not fit into visible area. (PR
   #229)
 - Extras: UI defaults inspector:

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

@@ -91,6 +91,9 @@ public class FlatSliderUI
 	protected Color disabledThumbColor;
 	protected Color disabledThumbBorderColor;
 
+	private Color defaultBackground;
+	private Color defaultForeground;
+
 	protected boolean thumbHover;
 	protected boolean thumbPressed;
 
@@ -131,6 +134,9 @@ public class FlatSliderUI
 		disabledTrackColor = UIManager.getColor( "Slider.disabledTrackColor" );
 		disabledThumbColor = UIManager.getColor( "Slider.disabledThumbColor" );
 		disabledThumbBorderColor = FlatUIUtils.getUIColor( "Slider.disabledThumbBorderColor", "Component.disabledBorderColor" );
+
+		defaultBackground = UIManager.getColor( "Slider.background" );
+		defaultForeground = UIManager.getColor( "Slider.foreground" );
 	}
 
 	@Override
@@ -149,6 +155,9 @@ public class FlatSliderUI
 		disabledTrackColor = null;
 		disabledThumbColor = null;
 		disabledThumbBorderColor = null;
+
+		defaultBackground = null;
+		defaultForeground = null;
 	}
 
 	@Override
@@ -289,25 +298,28 @@ debug*/
 				coloredTrack = temp;
 			}
 
-			g.setColor( trackValueColor );
+			g.setColor( getTrackValueColor() );
 			((Graphics2D)g).fill( coloredTrack );
 		}
 
-		g.setColor( enabled ? trackColor : disabledTrackColor );
+		g.setColor( enabled ? getTrackColor() : disabledTrackColor );
 		((Graphics2D)g).fill( track );
 	}
 
 	@Override
 	public void paintThumb( Graphics g ) {
+		Color thumbColor = getThumbColor();
 		Color color = stateColor( slider, thumbHover, thumbPressed,
 			thumbColor, disabledThumbColor, null, hoverThumbColor, pressedThumbColor );
 		color = FlatUIUtils.deriveColor( color, thumbColor );
 
-		Color borderColor = (thumbBorderColor != null)
+		Color foreground = slider.getForeground();
+		Color borderColor = (thumbBorderColor != null && foreground == defaultForeground)
 			? stateColor( slider, false, false, thumbBorderColor, disabledThumbBorderColor, focusedThumbBorderColor, null, null )
 			: null;
 
-		Color focusedColor = FlatUIUtils.deriveColor( this.focusedColor, focusBaseColor );
+		Color focusedColor = FlatUIUtils.deriveColor( this.focusedColor,
+			(foreground != defaultForeground) ? foreground : focusBaseColor );
 
 		paintThumb( g, slider, thumbRect, isRoundThumb(), color, borderColor, focusedColor, focusWidth );
 	}
@@ -436,6 +448,21 @@ debug*/
 		return path;
 	}
 
+	protected Color getTrackValueColor() {
+		Color foreground = slider.getForeground();
+		return (foreground != defaultForeground) ? foreground : trackValueColor;
+	}
+
+	protected Color getTrackColor() {
+		Color backround = slider.getBackground();
+		return (backround != defaultBackground) ? backround : trackColor;
+	}
+
+	protected Color getThumbColor() {
+		Color foreground = slider.getForeground();
+		return (foreground != defaultForeground) ? foreground : thumbColor;
+	}
+
 	public static Color stateColor( JSlider slider, boolean hover, boolean pressed,
 		Color enabledColor, Color disabledColor, Color focusedColor, Color hoverColor, Color pressedColor )
 	{

flatlaf-jide-oss/src/main/java/com/formdev/flatlaf/jideoss/ui/FlatRangeSliderUI.java

@@ -64,6 +64,9 @@ public class FlatRangeSliderUI
 	protected Color disabledThumbColor;
 	protected Color disabledThumbBorderColor;
 
+	private Color defaultBackground;
+	private Color defaultForeground;
+
 	private Object[] oldRenderingHints;
 
 	public static ComponentUI createUI( JComponent c ) {
@@ -129,6 +132,9 @@ public class FlatRangeSliderUI
 		disabledTrackColor = UIManager.getColor( "Slider.disabledTrackColor" );
 		disabledThumbColor = UIManager.getColor( "Slider.disabledThumbColor" );
 		disabledThumbBorderColor = FlatUIUtils.getUIColor( "Slider.disabledThumbBorderColor", "Component.disabledBorderColor" );
+
+		defaultBackground = UIManager.getColor( "Slider.background" );
+		defaultForeground = UIManager.getColor( "Slider.foreground" );
 	}
 
 	@Override
@@ -149,6 +155,9 @@ public class FlatRangeSliderUI
 		disabledTrackColor = null;
 		disabledThumbColor = null;
 		disabledThumbBorderColor = null;
+
+		defaultBackground = null;
+		defaultForeground = null;
 	}
 
 	@Override
@@ -278,13 +287,14 @@ debug*/
 			track = new RoundRectangle2D.Float( x, trackRect.y, tw, trackRect.height, arc, arc );
 		}
 
-		g.setColor( enabled ? trackColor : disabledTrackColor );
+		g.setColor( enabled ? getTrackColor() : disabledTrackColor );
 		((Graphics2D)g).fill( track );
 
 		if( coloredTrack != null ) {
 			boolean trackHover = hover && rollover1 && rollover2;
 			boolean trackPressed = pressed1 && pressed2;
 
+			Color trackValueColor = getTrackValueColor();
 			Color color = FlatSliderUI.stateColor( slider, trackHover, trackPressed,
 				trackValueColor, null, null, hoverTrackColor, pressedTrackColor );
 
@@ -298,19 +308,37 @@ debug*/
 		boolean thumbHover = hover && ((!second && rollover1) || (second && rollover2));
 		boolean thumbPressed = (!second && pressed1) || (second && pressed2);
 
+		Color thumbColor = getThumbColor();
 		Color color = FlatSliderUI.stateColor( slider, thumbHover, thumbPressed,
 			thumbColor, disabledThumbColor, null, hoverThumbColor, pressedThumbColor );
 		color = FlatUIUtils.deriveColor( color, thumbColor );
 
-		Color borderColor = (thumbBorderColor != null)
+		Color foreground = slider.getForeground();
+		Color borderColor = (thumbBorderColor != null && foreground == defaultForeground)
 			? FlatSliderUI.stateColor( slider, false, false, thumbBorderColor, disabledThumbBorderColor, focusedThumbBorderColor, null, null )
 			: null;
 
-		Color focusedColor = FlatUIUtils.deriveColor( this.focusedColor, focusBaseColor );
+		Color focusedColor = FlatUIUtils.deriveColor( this.focusedColor,
+			(foreground != defaultForeground) ? foreground : focusBaseColor );
 
 		FlatSliderUI.paintThumb( g, slider, thumbRect, isRoundThumb(), color, borderColor, focusedColor, focusWidth );
 	}
 
+	protected Color getTrackValueColor() {
+		Color foreground = slider.getForeground();
+		return (foreground != defaultForeground) ? foreground : trackValueColor;
+	}
+
+	protected Color getTrackColor() {
+		Color backround = slider.getBackground();
+		return (backround != defaultBackground) ? backround : trackColor;
+	}
+
+	protected Color getThumbColor() {
+		Color foreground = slider.getForeground();
+		return (foreground != defaultForeground) ? foreground : thumbColor;
+	}
+
 	protected boolean isRoundThumb() {
 		return !slider.getPaintTicks() && !slider.getPaintLabels();
 	}

flatlaf-testing/src/main/java/com/formdev/flatlaf/testing/FlatComponentsTest.java

@@ -214,6 +214,13 @@ public class FlatComponentsTest
 			slider.setSnapToTicks( snapToTicks );
 	}
 
+	private void sliderBorderChanged() {
+		boolean border = sliderBorderCheckBox.isSelected();
+		UIManager.put( "Slider.thumbBorderColor", border ? Color.green : null );
+		for( JSlider slider : allSliders )
+			slider.updateUI();
+	}
+
 	private void majorThickSpacingChanged() {
 		int majorTickSpacing = (Integer) majorTickSpacingSpinner.getValue();
 		for( JSlider slider : directionalSliders ) {
@@ -395,6 +402,7 @@ public class FlatComponentsTest
 		sliderInvertedCheckBox = new JCheckBox();
 		sliderSnapToTicksCheckBox = new JCheckBox();
 		majorTickSpacingSpinner = new JSpinner();
+		sliderBorderCheckBox = new JCheckBox();
 		minorTickSpacingSpinner = new JSpinner();
 		sliderValueLabel = new JLabel();
 		JPanel panel7 = new JPanel();
@@ -1381,10 +1389,15 @@ public class FlatComponentsTest
 				majorTickSpacingSpinner.addChangeListener(e -> majorThickSpacingChanged());
 				panel6.add(majorTickSpacingSpinner, "cell 0 2");
 
+				//---- sliderBorderCheckBox ----
+				sliderBorderCheckBox.setText("border");
+				sliderBorderCheckBox.addActionListener(e -> sliderBorderChanged());
+				panel6.add(sliderBorderCheckBox, "cell 0 2");
+
 				//---- minorTickSpacingSpinner ----
 				minorTickSpacingSpinner.setModel(new SpinnerNumberModel(10, 0, 100, 5));
 				minorTickSpacingSpinner.addChangeListener(e -> minorThickSpacingChanged());
-				panel6.add(minorTickSpacingSpinner, "cell 0 2");
+				panel6.add(minorTickSpacingSpinner, "cell 0 3");
 
 				//---- sliderValueLabel ----
 				sliderValueLabel.setText("slider value");
@@ -1625,6 +1638,7 @@ public class FlatComponentsTest
 	private JCheckBox sliderInvertedCheckBox;
 	private JCheckBox sliderSnapToTicksCheckBox;
 	private JSpinner majorTickSpacingSpinner;
+	private JCheckBox sliderBorderCheckBox;
 	private JSpinner minorTickSpacingSpinner;
 	private JLabel sliderValueLabel;
 	private JCheckBox indeterminateCheckBox;

flatlaf-testing/src/main/java/com/formdev/flatlaf/testing/FlatComponentsTest.jfd

@@ -1243,6 +1243,16 @@ new FormModel {
 					}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
 						"value": "cell 0 2"
 					} )
+					add( new FormComponent( "javax.swing.JCheckBox" ) {
+						name: "sliderBorderCheckBox"
+						"text": "border"
+						auxiliary() {
+							"JavaCodeGenerator.variableLocal": false
+						}
+						addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "sliderBorderChanged", false ) )
+					}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+						"value": "cell 0 2"
+					} )
 					add( new FormComponent( "javax.swing.JSpinner" ) {
 						name: "minorTickSpacingSpinner"
 						"model": new javax.swing.SpinnerNumberModel( 10, 0, 100, 5 )
@@ -1251,7 +1261,7 @@ new FormModel {
 						}
 						addEvent( new FormEvent( "javax.swing.event.ChangeListener", "stateChanged", "minorThickSpacingChanged", false ) )
 					}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
-						"value": "cell 0 2"
+						"value": "cell 0 3"
 					} )
 					add( new FormComponent( "javax.swing.JLabel" ) {
 						name: "sliderValueLabel"

flatlaf-testing/src/main/java/com/formdev/flatlaf/testing/FlatTestFrame.java

@@ -446,7 +446,7 @@ public class FlatTestFrame
 			Color green = dark ? Color.green.darker() : Color.green;
 
 			updateComponentsRecur( content, (c, type) -> {
-				if( type == "view" || type == "tab" ) {
+				if( type == "view" || type == "tab" || c instanceof JSlider ) {
 					c.setForeground( explicit ? magenta : restoreColor );
 					c.setBackground( explicit ? orange : restoreColor );
 				} else {