TabbedPane: support specifying tab insets via client property

flatlaf-core/src/main/java/com/formdev/flatlaf/FlatClientProperties.java

@@ -254,6 +254,15 @@ public interface FlatClientProperties
 	 */
 	String TABBED_PANE_TAB_HEIGHT = "JTabbedPane.tabHeight";
 
+	/**
+	 * Specifies the insets of a tab.
+	 * <p>
+	 * <strong>Component</strong> {@link javax.swing.JTabbedPane}
+	 * or tab content components (see {@link javax.swing.JTabbedPane#setComponentAt(int, java.awt.Component)})<br>
+	 * <strong>Value type</strong> {@link java.awt.Insets}
+	 */
+	String TABBED_PANE_TAB_INSETS = "JTabbedPane.tabInsets";
+
 	/**
 	 * Specifies whether tabs are closable.
 	 * If set to {@code true} on a tabbed pane component, all tabs in that tabbed pane are closable.

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

@@ -529,6 +529,14 @@ public class FlatTabbedPaneUI
 		return Math.max( tabHeight, super.calculateTabHeight( tabPlacement, tabIndex, fontHeight ) - 2 /* was added by superclass */ );
 	}
 
+	@Override
+	protected Insets getTabInsets( int tabPlacement, int tabIndex ) {
+		Object value = getTabClientProperty( tabIndex, TABBED_PANE_TAB_INSETS );
+		return (value instanceof Insets)
+			? scale( (Insets) value )
+			: super.getTabInsets( tabPlacement, tabIndex );
+	}
+
 	@Override
 	protected Insets getTabAreaInsets( int tabPlacement ) {
 		Insets currentTabAreaInsets = super.getTabAreaInsets( tabPlacement );
@@ -1503,6 +1511,8 @@ public class FlatTabbedPaneUI
 		PropertyChangeListener propertyChangeDelegate;
 		ChangeListener changeDelegate;
 
+		private final PropertyChangeListener contentListener = this::contentPropertyChange;
+
 		private int pressedTabIndex = -1;
 
 		void installListeners() {
@@ -1512,7 +1522,7 @@ public class FlatTabbedPaneUI
 
 			for( Component c : tabPane.getComponents() ) {
 				if( !(c instanceof UIResource) )
-					c.addPropertyChangeListener( TABBED_PANE_TAB_CLOSABLE, this );
+					c.addPropertyChangeListener( contentListener );
 			}
 		}
 
@@ -1523,7 +1533,7 @@ public class FlatTabbedPaneUI
 
 			for( Component c : tabPane.getComponents() ) {
 				if( !(c instanceof UIResource) )
-					c.removePropertyChangeListener( TABBED_PANE_TAB_CLOSABLE, this );
+					c.removePropertyChangeListener( contentListener );
 			}
 		}
 
@@ -1604,21 +1614,19 @@ public class FlatTabbedPaneUI
 		@Override
 		public void propertyChange( PropertyChangeEvent e ) {
 			// invoke delegate listener
-			if( e.getSource() instanceof JTabbedPane ) {
+			switch( e.getPropertyName() ) {
-				switch( e.getPropertyName() ) {
+				case "tabPlacement":
-					case "tabPlacement":
+				case "opaque":
-					case "opaque":
+				case "background":
-					case "background":
+				case "indexForTabComponent":
-					case "indexForTabComponent":
+					runWithOriginalLayoutManager( () -> {
-						runWithOriginalLayoutManager( () -> {
-							propertyChangeDelegate.propertyChange( e );
-						} );
-						break;
-
-					default:
 						propertyChangeDelegate.propertyChange( e );
-						break;
+					} );
-				}
+					break;
+
+				default:
+					propertyChangeDelegate.propertyChange( e );
+					break;
 			}
 
 			// handle event
@@ -1636,6 +1644,7 @@ public class FlatTabbedPaneUI
 				case TABBED_PANE_SHOW_CONTENT_SEPARATOR:
 				case TABBED_PANE_HAS_FULL_BORDER:
 				case TABBED_PANE_TAB_HEIGHT:
+				case TABBED_PANE_TAB_INSETS:
 				case TABBED_PANE_HIDDEN_TABS_NAVIGATION:
 				case TABBED_PANE_TAB_CLOSABLE:
 					tabPane.revalidate();
@@ -1671,6 +1680,16 @@ public class FlatTabbedPaneUI
 				ensureSelectedTabIsVisible();
 		}
 
+		protected void contentPropertyChange( PropertyChangeEvent e ) {
+			switch( e.getPropertyName() ) {
+				case TABBED_PANE_TAB_INSETS:
+				case TABBED_PANE_TAB_CLOSABLE:
+					tabPane.revalidate();
+					tabPane.repaint();
+					break;
+			}
+		}
+
 		//---- interface ComponentListener ----
 
 		@Override
@@ -1689,14 +1708,14 @@ public class FlatTabbedPaneUI
 		public void componentAdded( ContainerEvent e ) {
 			Component c = e.getChild();
 			if( !(c instanceof UIResource) )
-				c.addPropertyChangeListener( TABBED_PANE_TAB_CLOSABLE, this );
+				c.addPropertyChangeListener( contentListener );
 		}
 
 		@Override
 		public void componentRemoved( ContainerEvent e ) {
 			Component c = e.getChild();
 			if( !(c instanceof UIResource) )
-				c.removePropertyChangeListener( TABBED_PANE_TAB_CLOSABLE, this );
+				c.removePropertyChangeListener( contentListener );
 		}
 	}
 

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

@@ -299,6 +299,26 @@ public class FlatContainerTest
 		}
 	}
 
+	private void smallerTabHeightChanged() {
+		Integer tabHeight = smallerTabHeightCheckBox.isSelected() ? 20 : null;
+		putTabbedPanesClientProperty( TABBED_PANE_TAB_HEIGHT, tabHeight );
+	}
+
+	private void smallerInsetsChanged() {
+		Insets insets = smallerInsetsCheckBox.isSelected() ? new Insets( 2, 2, 2, 2 ) : null;
+		putTabbedPanesClientProperty( TABBED_PANE_TAB_INSETS, insets );
+	}
+
+	private void secondTabWiderChanged() {
+		Insets insets = secondTabWiderCheckBox.isSelected() ? new Insets( 4, 20, 4, 20 ) : null;
+
+		JTabbedPane[] tabbedPanes = new JTabbedPane[] { tabbedPane1, tabbedPane2, tabbedPane3, tabbedPane4 };
+		for( JTabbedPane tabbedPane : tabbedPanes ) {
+			Component c = tabbedPane.getComponentAt( 1 );
+			((JComponent)c).putClientProperty( TABBED_PANE_TAB_INSETS, insets );
+		}
+	}
+
 	private void initComponents() {
 		// JFormDesigner - Component initialization - DO NOT MODIFY  //GEN-BEGIN:initComponents
 		JPanel panel9 = new JPanel();
@@ -337,6 +357,9 @@ public class FlatContainerTest
 		trailingComponentCheckBox = new JCheckBox();
 		tabsClosableCheckBox = new JCheckBox();
 		secondTabClosableCheckBox = new TriStateCheckBox();
+		smallerTabHeightCheckBox = new JCheckBox();
+		smallerInsetsCheckBox = new JCheckBox();
+		secondTabWiderCheckBox = new JCheckBox();
 		CellConstraints cc = new CellConstraints();
 
 		//======== this ========
@@ -451,6 +474,7 @@ public class FlatContainerTest
 					"[center]" +
 					"[]" +
 					"[]" +
+					"[]" +
 					"[]"));
 
 				//---- moreTabsCheckBox ----
@@ -559,6 +583,21 @@ public class FlatContainerTest
 				secondTabClosableCheckBox.setText("Second Tab closable");
 				secondTabClosableCheckBox.addActionListener(e -> secondTabClosableChanged());
 				panel14.add(secondTabClosableCheckBox, "cell 3 3");
+
+				//---- smallerTabHeightCheckBox ----
+				smallerTabHeightCheckBox.setText("Smaller tab height");
+				smallerTabHeightCheckBox.addActionListener(e -> smallerTabHeightChanged());
+				panel14.add(smallerTabHeightCheckBox, "cell 0 4 2 1");
+
+				//---- smallerInsetsCheckBox ----
+				smallerInsetsCheckBox.setText("Smaller insets");
+				smallerInsetsCheckBox.addActionListener(e -> smallerInsetsChanged());
+				panel14.add(smallerInsetsCheckBox, "cell 2 4");
+
+				//---- secondTabWiderCheckBox ----
+				secondTabWiderCheckBox.setText("Second Tab wider");
+				secondTabWiderCheckBox.addActionListener(e -> secondTabWiderChanged());
+				panel14.add(secondTabWiderCheckBox, "cell 3 4");
 			}
 			panel9.add(panel14, cc.xywh(1, 11, 3, 1));
 		}
@@ -588,6 +627,9 @@ public class FlatContainerTest
 	private JCheckBox trailingComponentCheckBox;
 	private JCheckBox tabsClosableCheckBox;
 	private TriStateCheckBox secondTabClosableCheckBox;
+	private JCheckBox smallerTabHeightCheckBox;
+	private JCheckBox smallerInsetsCheckBox;
+	private JCheckBox secondTabWiderCheckBox;
 	// JFormDesigner - End of variables declaration  //GEN-END:variables
 
 	//---- class Tab1Panel ----------------------------------------------------

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

@@ -132,7 +132,7 @@ new FormModel {
 				add( new FormContainer( "javax.swing.JPanel", new FormLayoutManager( class net.miginfocom.swing.MigLayout ) {
 					"$layoutConstraints": "insets 0,hidemode 3"
 					"$columnConstraints": "[][fill][][][fill]"
-					"$rowConstraints": "[center][][][]"
+					"$rowConstraints": "[center][][][][]"
 				} ) {
 					name: "panel14"
 					"opaque": false
@@ -347,6 +347,36 @@ new FormModel {
 					}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
 						"value": "cell 3 3"
 					} )
+					add( new FormComponent( "javax.swing.JCheckBox" ) {
+						name: "smallerTabHeightCheckBox"
+						"text": "Smaller tab height"
+						auxiliary() {
+							"JavaCodeGenerator.variableLocal": false
+						}
+						addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "smallerTabHeightChanged", false ) )
+					}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+						"value": "cell 0 4 2 1"
+					} )
+					add( new FormComponent( "javax.swing.JCheckBox" ) {
+						name: "smallerInsetsCheckBox"
+						"text": "Smaller insets"
+						auxiliary() {
+							"JavaCodeGenerator.variableLocal": false
+						}
+						addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "smallerInsetsChanged", false ) )
+					}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+						"value": "cell 2 4"
+					} )
+					add( new FormComponent( "javax.swing.JCheckBox" ) {
+						name: "secondTabWiderCheckBox"
+						"text": "Second Tab wider"
+						auxiliary() {
+							"JavaCodeGenerator.variableLocal": false
+						}
+						addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "secondTabWiderChanged", false ) )
+					}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+						"value": "cell 3 4"
+					} )
 				}, new FormLayoutConstraints( class com.jgoodies.forms.layout.CellConstraints ) {
 					"gridY": 11
 					"gridWidth": 3