Made JComboBox, JProgressBar, JSpinner and JXDatePicker non-opaque.

`JPasswordField`, `JScrollPane` and `JTextField` are non-opaque if they have
an outside focus border (e.g. IntelliJ and Darcula themes).
(issues #20 and #17)

CHANGELOG.md

@@ -6,6 +6,10 @@ FlatLaf Change Log
 - CheckBox: Support painting a third state (set client property
   "JButton.selectedState" to "indeterminate").
 - `TriStateCheckBox` component added (see [FlatLaf Extras](flatlaf-extras)).
+- Made `JComboBox`, `JProgressBar`, `JSpinner` and `JXDatePicker` non-opaque.
+  `JPasswordField`, `JScrollPane` and `JTextField` are non-opaque if they have
+  an outside focus border (e.g. IntelliJ and Darcula themes). (issues #20 and
+  #17)
 
 
 ## 0.16

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

@@ -41,6 +41,7 @@ import javax.swing.JComponent;
 import javax.swing.JList;
 import javax.swing.JPanel;
 import javax.swing.ListCellRenderer;
+import javax.swing.LookAndFeel;
 import javax.swing.SwingConstants;
 import javax.swing.UIManager;
 import javax.swing.border.AbstractBorder;
@@ -123,6 +124,8 @@ public class FlatComboBoxUI
 	protected void installDefaults() {
 		super.installDefaults();
 
+		LookAndFeel.installProperty( comboBox, "opaque", false );
+
 		focusWidth = UIManager.getInt( "Component.focusWidth" );
 		arc = UIManager.getInt( "Component.arc" );
 		arrowType = UIManager.getString( "Component.arrowType" );
@@ -271,44 +274,44 @@ public class FlatComboBoxUI
 
 	@Override
 	public void update( Graphics g, JComponent c ) {
-		if( c.isOpaque() ) {
+		// fill background if opaque to avoid garbage if user sets opaque to true
+		if( c.isOpaque() )
 			FlatUIUtils.paintParentBackground( g, c );
 
-			Graphics2D g2 = (Graphics2D) g;
+		Graphics2D g2 = (Graphics2D) g;
-			FlatUIUtils.setRenderingHints( g2 );
+		FlatUIUtils.setRenderingHints( g2 );
 
-			int width = c.getWidth();
+		int width = c.getWidth();
-			int height = c.getHeight();
+		int height = c.getHeight();
-			float focusWidth = (c.getBorder() instanceof FlatBorder) ? scale( (float) this.focusWidth ) : 0;
+		float focusWidth = (c.getBorder() instanceof FlatBorder) ? scale( (float) this.focusWidth ) : 0;
-			float arc = (c.getBorder() instanceof FlatRoundBorder) ? scale( (float) this.arc ) : 0;
+		float arc = (c.getBorder() instanceof FlatRoundBorder) ? scale( (float) this.arc ) : 0;
-			int arrowX = arrowButton.getX();
+		int arrowX = arrowButton.getX();
-			int arrowWidth = arrowButton.getWidth();
+		int arrowWidth = arrowButton.getWidth();
-			boolean enabled = comboBox.isEnabled();
+		boolean enabled = comboBox.isEnabled();
-			boolean isLeftToRight = comboBox.getComponentOrientation().isLeftToRight();
+		boolean isLeftToRight = comboBox.getComponentOrientation().isLeftToRight();
 
-			// paint background
+		// paint background
-			g2.setColor( enabled ? c.getBackground() : disabledBackground );
+		g2.setColor( enabled ? c.getBackground() : disabledBackground );
+		FlatUIUtils.fillRoundRectangle( g2, 0, 0, width, height, focusWidth, arc );
+
+		// paint arrow button background
+		if( enabled ) {
+			g2.setColor( comboBox.isEditable() ? buttonEditableBackground : buttonBackground );
+			Shape oldClip = g2.getClip();
+			if( isLeftToRight )
+				g2.clipRect( arrowX, 0, width - arrowX, height );
+			else
+				g2.clipRect( 0, 0, arrowX + arrowWidth, height );
 			FlatUIUtils.fillRoundRectangle( g2, 0, 0, width, height, focusWidth, arc );
+			g2.setClip( oldClip );
+		}
 
-			// paint arrow button background
+		// paint vertical line between value and arrow button
-			if( enabled ) {
+		if( comboBox.isEditable() ) {
-				g2.setColor( comboBox.isEditable() ? buttonEditableBackground : buttonBackground );
+			g2.setColor( enabled ? borderColor : disabledBorderColor );
-				Shape oldClip = g2.getClip();
+			float lw = scale( 1f );
-				if( isLeftToRight )
+			float lx = isLeftToRight ? arrowX : arrowX + arrowWidth - lw;
-					g2.clipRect( arrowX, 0, width - arrowX, height );
+			g2.fill( new Rectangle2D.Float( lx, focusWidth, lw, height - (focusWidth * 2) ) );
-				else
-					g2.clipRect( 0, 0, arrowX + arrowWidth, height );
-				FlatUIUtils.fillRoundRectangle( g2, 0, 0, width, height, focusWidth, arc );
-				g2.setClip( oldClip );
-			}
-
-			if( comboBox.isEditable() ) {
-				// paint vertical line between value and arrow button
-				g2.setColor( enabled ? borderColor : disabledBorderColor );
-				float lw = scale( 1f );
-				float lx = isLeftToRight ? arrowX : arrowX + arrowWidth - lw;
-				g2.fill( new Rectangle2D.Float( lx, focusWidth, lw, height - (focusWidth * 2) ) );
-			}
 		}
 
 		paint( g, c );

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

@@ -60,6 +60,8 @@ public class FlatPasswordFieldUI
 		focusWidth = UIManager.getInt( "Component.focusWidth" );
 		minimumWidth = UIManager.getInt( "Component.minimumWidth" );
 
+		LookAndFeel.installProperty( getComponent(), "opaque", focusWidth == 0 );
+
 		MigLayoutVisualPadding.install( getComponent(), focusWidth );
 	}
 
@@ -87,8 +89,14 @@ public class FlatPasswordFieldUI
 	}
 
 	@Override
-	protected void paintBackground( Graphics g ) {
+	protected void paintSafely( Graphics g ) {
 		FlatTextFieldUI.paintBackground( g, getComponent(), focusWidth );
+		super.paintSafely( g );
+	}
+
+	@Override
+	protected void paintBackground( Graphics g ) {
+		// background is painted elsewhere
 	}
 
 	@Override

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

@@ -23,6 +23,7 @@ import java.awt.Insets;
 import java.awt.geom.RoundRectangle2D;
 import javax.swing.JComponent;
 import javax.swing.JProgressBar;
+import javax.swing.LookAndFeel;
 import javax.swing.plaf.ComponentUI;
 import javax.swing.plaf.basic.BasicProgressBarUI;
 import com.formdev.flatlaf.util.UIScale;
@@ -39,6 +40,13 @@ public class FlatProgressBarUI
 		return new FlatProgressBarUI();
 	}
 
+	@Override
+	protected void installDefaults() {
+		super.installDefaults();
+
+		LookAndFeel.installProperty( progressBar, "opaque", false );
+	}
+
 	@Override
 	protected Dimension getPreferredInnerHorizontal() {
 		return UIScale.scale( super.getPreferredInnerHorizontal() );

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

@@ -29,6 +29,7 @@ import java.beans.PropertyChangeEvent;
 import javax.swing.JComponent;
 import javax.swing.JScrollPane;
 import javax.swing.JViewport;
+import javax.swing.LookAndFeel;
 import javax.swing.ScrollPaneLayout;
 import javax.swing.UIManager;
 import javax.swing.plaf.ComponentUI;
@@ -56,7 +57,10 @@ public class FlatScrollPaneUI
 		if( scrollpane.getLayout() instanceof UIResource )
 			scrollpane.setLayout( new FlatScrollPaneLayout() );
 
-		MigLayoutVisualPadding.install( scrollpane, UIManager.getInt( "Component.focusWidth" ) );
+		int focusWidth = UIManager.getInt( "Component.focusWidth" );
+		LookAndFeel.installProperty( c, "opaque", focusWidth == 0 );
+
+		MigLayoutVisualPadding.install( scrollpane, focusWidth );
 	}
 
 	@Override

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

@@ -35,6 +35,7 @@ import java.beans.PropertyChangeListener;
 import javax.swing.JComponent;
 import javax.swing.JSpinner;
 import javax.swing.JTextField;
+import javax.swing.LookAndFeel;
 import javax.swing.SwingConstants;
 import javax.swing.UIManager;
 import javax.swing.plaf.ComponentUI;
@@ -88,6 +89,8 @@ public class FlatSpinnerUI
 	protected void installDefaults() {
 		super.installDefaults();
 
+		LookAndFeel.installProperty( spinner, "opaque", false );
+
 		focusWidth = UIManager.getInt( "Component.focusWidth" );
 		arc = UIManager.getInt( "Component.arc" );
 		minimumWidth = UIManager.getInt( "Component.minimumWidth" );
@@ -225,45 +228,45 @@ public class FlatSpinnerUI
 
 	@Override
 	public void update( Graphics g, JComponent c ) {
-		if( c.isOpaque() ) {
+		// fill background if opaque to avoid garbage if user sets opaque to true
+		if( c.isOpaque() )
 			FlatUIUtils.paintParentBackground( g, c );
 
-			Graphics2D g2 = (Graphics2D) g;
+		Graphics2D g2 = (Graphics2D) g;
-			FlatUIUtils.setRenderingHints( g2 );
+		FlatUIUtils.setRenderingHints( g2 );
 
-			int width = c.getWidth();
+		int width = c.getWidth();
-			int height = c.getHeight();
+		int height = c.getHeight();
-			float focusWidth = (c.getBorder() instanceof FlatBorder) ? scale( (float) this.focusWidth ) : 0;
+		float focusWidth = (c.getBorder() instanceof FlatBorder) ? scale( (float) this.focusWidth ) : 0;
-			float arc = (c.getBorder() instanceof FlatRoundBorder) ? scale( (float) this.arc ) : 0;
+		float arc = (c.getBorder() instanceof FlatRoundBorder) ? scale( (float) this.arc ) : 0;
-			Component nextButton = getHandler().nextButton;
+		Component nextButton = getHandler().nextButton;
-			int arrowX = nextButton.getX();
+		int arrowX = nextButton.getX();
-			int arrowWidth = nextButton.getWidth();
+		int arrowWidth = nextButton.getWidth();
-			boolean enabled = spinner.isEnabled();
+		boolean enabled = spinner.isEnabled();
-			boolean isLeftToRight = spinner.getComponentOrientation().isLeftToRight();
+		boolean isLeftToRight = spinner.getComponentOrientation().isLeftToRight();
 
-			// paint background
+		// paint background
-			g2.setColor( enabled ? c.getBackground() : disabledBackground );
+		g2.setColor( enabled ? c.getBackground() : disabledBackground );
+		FlatUIUtils.fillRoundRectangle( g2, 0, 0, width, height, focusWidth, arc );
+
+		// paint arrow buttons background
+		if( enabled ) {
+			g2.setColor( buttonBackground );
+			Shape oldClip = g2.getClip();
+			if( isLeftToRight )
+				g2.clipRect( arrowX, 0, width - arrowX, height );
+			else
+				g2.clipRect( 0, 0, arrowX + arrowWidth, height );
 			FlatUIUtils.fillRoundRectangle( g2, 0, 0, width, height, focusWidth, arc );
-
+			g2.setClip( oldClip );
-			// paint arrow buttons background
-			if( enabled ) {
-				g2.setColor( buttonBackground );
-				Shape oldClip = g2.getClip();
-				if( isLeftToRight )
-					g2.clipRect( arrowX, 0, width - arrowX, height );
-				else
-					g2.clipRect( 0, 0, arrowX + arrowWidth, height );
-				FlatUIUtils.fillRoundRectangle( g2, 0, 0, width, height, focusWidth, arc );
-				g2.setClip( oldClip );
-			}
-
-			// paint vertical line between value and arrow buttons
-			g2.setColor( enabled ? borderColor : disabledBorderColor );
-			float lw = scale( 1f );
-			float lx = isLeftToRight ? arrowX : arrowX + arrowWidth - lw;
-			g2.fill( new Rectangle2D.Float( lx, focusWidth, lw, height - (focusWidth * 2) ) );
 		}
 
+		// paint vertical line between value and arrow buttons
+		g2.setColor( enabled ? borderColor : disabledBorderColor );
+		float lw = scale( 1f );
+		float lx = isLeftToRight ? arrowX : arrowX + arrowWidth - lw;
+		g2.fill( new Rectangle2D.Float( lx, focusWidth, lw, height - (focusWidth * 2) ) );
+
 		paint( g, c );
 	}
 

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

@@ -25,6 +25,7 @@ import java.awt.event.FocusListener;
 import javax.swing.JComboBox;
 import javax.swing.JComponent;
 import javax.swing.JSpinner;
+import javax.swing.LookAndFeel;
 import javax.swing.UIManager;
 import javax.swing.plaf.ComponentUI;
 import javax.swing.plaf.basic.BasicTextFieldUI;
@@ -59,6 +60,8 @@ public class FlatTextFieldUI
 		focusWidth = UIManager.getInt( "Component.focusWidth" );
 		minimumWidth = UIManager.getInt( "Component.minimumWidth" );
 
+		LookAndFeel.installProperty( getComponent(), "opaque", focusWidth == 0 );
+
 		MigLayoutVisualPadding.install( getComponent(), focusWidth );
 	}
 
@@ -86,13 +89,30 @@ public class FlatTextFieldUI
 	}
 
 	@Override
-	protected void paintBackground( Graphics g ) {
+	protected void paintSafely( Graphics g ) {
 		paintBackground( g, getComponent(), focusWidth );
+		super.paintSafely( g );
+	}
+
+	@Override
+	protected void paintBackground( Graphics g ) {
+		// background is painted elsewhere
 	}
 
 	static void paintBackground( Graphics g, JTextComponent c, int focusWidth ) {
-		FlatUIUtils.paintParentBackground( g, c );
+		// do not paint background if:
+		//   - not opaque and
+		//   - border is not a flat border and
+		//   - opaque was explicitly set (to false)
+		// (same behaviour as in AquaTextFieldUI)
+		if( !c.isOpaque() && !(c.getBorder() instanceof FlatBorder) && FlatUIUtils.hasOpaqueBeenExplicitlySet( c ) )
+			return;
 
+		// fill background if opaque to avoid garbage if user sets opaque to true
+		if( c.isOpaque() && focusWidth > 0 )
+			FlatUIUtils.paintParentBackground( g, c );
+
+		// paint background
 		Graphics2D g2 = (Graphics2D) g.create();
 		try {
 			FlatUIUtils.setRenderingHints( g2 );

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

@@ -35,6 +35,7 @@ import java.awt.geom.Rectangle2D;
 import java.awt.geom.RoundRectangle2D;
 import java.util.function.Consumer;
 import javax.swing.JComponent;
+import javax.swing.LookAndFeel;
 import javax.swing.UIManager;
 import javax.swing.plaf.ColorUIResource;
 import com.formdev.flatlaf.util.JavaCompatibility;
@@ -248,6 +249,14 @@ public class FlatUIUtils
 		JavaCompatibility.drawStringUnderlineCharAt( c, g, text, underlinedIndex, x, y );
 	}
 
+	public static boolean hasOpaqueBeenExplicitlySet( JComponent c ) {
+		boolean oldOpaque = c.isOpaque();
+		LookAndFeel.installProperty( c, "opaque", !oldOpaque );
+		boolean explicitlySet = c.isOpaque() == oldOpaque;
+		LookAndFeel.installProperty( c, "opaque", oldOpaque );
+		return explicitlySet;
+	}
+
 	//---- class HoverListener ------------------------------------------------
 
 	public static class HoverListener

flatlaf-swingx/src/main/java/com/formdev/flatlaf/swingx/ui/FlatDatePickerUI.java

@@ -103,6 +103,8 @@ public class FlatDatePickerUI
 
 		super.installUI( c );
 
+		LookAndFeel.installProperty( datePicker, "opaque", false );
+
 		// hack JXDatePicker.TodayPanel colors
 		// (there is no need to uninstall these changes because only UIResources are used,
 		// which are automatically replaced when switching LaF)
@@ -217,44 +219,44 @@ public class FlatDatePickerUI
 
 	@Override
 	public void update( Graphics g, JComponent c ) {
-		if( c.isOpaque() ) {
+		// fill background if opaque to avoid garbage if user sets opaque to true
+		if( c.isOpaque() )
 			FlatUIUtils.paintParentBackground( g, c );
 
-			Graphics2D g2 = (Graphics2D) g;
+		Graphics2D g2 = (Graphics2D) g;
-			FlatUIUtils.setRenderingHints( g2 );
+		FlatUIUtils.setRenderingHints( g2 );
 
-			int width = c.getWidth();
+		int width = c.getWidth();
-			int height = c.getHeight();
+		int height = c.getHeight();
-			float focusWidth = (c.getBorder() instanceof FlatBorder) ? scale( (float) this.focusWidth ) : 0;
+		float focusWidth = (c.getBorder() instanceof FlatBorder) ? scale( (float) this.focusWidth ) : 0;
-			float arc = (c.getBorder() instanceof FlatRoundBorder) ? scale( (float) this.arc ) : 0;
+		float arc = (c.getBorder() instanceof FlatRoundBorder) ? scale( (float) this.arc ) : 0;
-			int arrowX = popupButton.getX();
+		int arrowX = popupButton.getX();
-			int arrowWidth = popupButton.getWidth();
+		int arrowWidth = popupButton.getWidth();
-			boolean enabled = c.isEnabled();
+		boolean enabled = c.isEnabled();
-			boolean isLeftToRight = c.getComponentOrientation().isLeftToRight();
+		boolean isLeftToRight = c.getComponentOrientation().isLeftToRight();
 
-			// paint background
+		// paint background
-			g2.setColor( enabled ? c.getBackground() : disabledBackground );
+		g2.setColor( enabled ? c.getBackground() : disabledBackground );
+		FlatUIUtils.fillRoundRectangle( g2, 0, 0, width, height, focusWidth, arc );
+
+		// paint arrow button background
+		if( enabled ) {
+			g2.setColor( buttonBackground );
+			Shape oldClip = g2.getClip();
+			if( isLeftToRight )
+				g2.clipRect( arrowX, 0, width - arrowX, height );
+			else
+				g2.clipRect( 0, 0, arrowX + arrowWidth, height );
 			FlatUIUtils.fillRoundRectangle( g2, 0, 0, width, height, focusWidth, arc );
-
+			g2.setClip( oldClip );
-			// paint arrow button background
-			if( enabled ) {
-				g2.setColor( buttonBackground );
-				Shape oldClip = g2.getClip();
-				if( isLeftToRight )
-					g2.clipRect( arrowX, 0, width - arrowX, height );
-				else
-					g2.clipRect( 0, 0, arrowX + arrowWidth, height );
-				FlatUIUtils.fillRoundRectangle( g2, 0, 0, width, height, focusWidth, arc );
-				g2.setClip( oldClip );
-			}
-
-			// paint vertical line between value and arrow button
-			g2.setColor( enabled ? borderColor : disabledBorderColor );
-			float lw = scale( 1f );
-			float lx = isLeftToRight ? arrowX : arrowX + arrowWidth - lw;
-			g2.fill( new Rectangle2D.Float( lx, focusWidth, lw, height - (focusWidth * 2) ) );
 		}
 
+		// paint vertical line between value and arrow button
+		g2.setColor( enabled ? borderColor : disabledBorderColor );
+		float lw = scale( 1f );
+		float lx = isLeftToRight ? arrowX : arrowX + arrowWidth - lw;
+		g2.fill( new Rectangle2D.Float( lx, focusWidth, lw, height - (focusWidth * 2) ) );
+
 		paint( g, c );
 	}
 

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

@@ -58,6 +58,7 @@ public class FlatInspector
 	private Component lastComponent;
 	private int lastX;
 	private int lastY;
+	private boolean inspectParent;
 
 	private JComponent highlightFigure;
 	private JToolTip tip;
@@ -70,6 +71,7 @@ public class FlatInspector
 			public void mouseMoved( MouseEvent e ) {
 				lastX = e.getX();
 				lastY = e.getY();
+				inspectParent = e.isShiftDown();
 				inspect( lastX, lastY );
 			}
 		} );
@@ -105,6 +107,8 @@ public class FlatInspector
 	private void inspect( int x, int y ) {
 		Container contentPane = rootPane.getContentPane();
 		Component c = SwingUtilities.getDeepestComponentAt( contentPane, x, y );
+		if( inspectParent && c != null && c != contentPane )
+			c = c.getParent();
 		if( c == contentPane || (c != null && c.getParent() == contentPane) )
 			c = null;
 
@@ -237,7 +241,8 @@ public class FlatInspector
 		}
 
 		text += "Enabled: " + c.isEnabled() + '\n';
-		text += "Opaque: " + c.isOpaque() + '\n';
+		text += "Opaque: " + c.isOpaque() + (c instanceof JComponent &&
+			FlatUIUtils.hasOpaqueBeenExplicitlySet( (JComponent) c ) ? " EXPLICIT" : "") + '\n';
 		text += "Focusable: " + c.isFocusable() + '\n';
 		text += "Left-to-right: " + c.getComponentOrientation().isLeftToRight() + '\n';
 		text += "Parent: " + c.getParent().getClass().getName();

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

@@ -307,7 +307,7 @@ public class FlatTestFrame
 					c.setBackground( explicit ? Color.orange : restoreColor );
 				} else {
 					c.setForeground( explicit ? Color.blue : restoreColor );
-					c.setBackground( explicit ? Color.red : restoreColor );
+					c.setBackground( explicit ? Color.green : restoreColor );
 				}
 			} );
 
@@ -425,6 +425,14 @@ public class FlatTestFrame
 		contentPanel.getContentPane().remove( content );
 		content = contentFactory.get();
 		contentPanel.getContentPane().add( content );
+
+		if( rightToLeftCheckBox.isSelected() )
+			rightToLeftChanged();
+		if( !enabledCheckBox.isSelected() )
+			enabledChanged();
+		if( explicitColorsCheckBox.isSelected() )
+			explicitColorsChanged();
+
 		contentPanel.revalidate();
 		contentPanel.repaint();
 	}

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

@@ -29,15 +29,29 @@ public class FlatTestPanel
 {
 	@Override
 	protected void paintComponent( Graphics g ) {
-		super.paintComponent( g );
+		int width = getWidth();
+		int height = getHeight();
 
-		FlatTestFrame frame = (FlatTestFrame) SwingUtilities.getAncestorOfClass( FlatTestFrame.class, this );
+		g.setColor( super.getBackground() );
-		if( frame != null && frame.isPaintBackgroundPattern() ) {
+		g.fillRect( 0, 0, width, height );
+
+		if( isPaintBackgroundPattern() ) {
 			g.setColor( Color.magenta );
-			int width = getWidth();
-			int height = getHeight();
 			for( int y = 0; y < height; y += 2 )
 				g.drawLine( 0, y, width - 1, y );
 		}
 	}
+
+	/**
+	 * Overridden to see which components paint background with color from parent.
+	 */
+	@Override
+	public Color getBackground() {
+		return isPaintBackgroundPattern() ? Color.red : super.getBackground();
+	}
+
+	private boolean isPaintBackgroundPattern() {
+		FlatTestFrame frame = (FlatTestFrame) SwingUtilities.getAncestorOfClass( FlatTestFrame.class, this );
+		return frame != null && frame.isPaintBackgroundPattern();
+	}
 }