TabbedPane: support minimum and maximum tab widths

CHANGELOG.md

@@ -19,6 +19,8 @@ FlatLaf Change Log
   `JTabbedPane.trailingComponent` to a `java.awt.Component`) (PR #192; issue
   #40)
 - TabbedPane: Support closable tabs. (PR #193; issues #31 and #40)
+- TabbedPane: Support minimum or maximum tab widths. (set client property
+  `JTabbedPane.minimumTabWidth` or `JTabbedPane.maximumTabWidth` to an integer)
 - Support painting separator line between window title and content (use UI value
   `TitlePane.borderColor`). (issue #184)
 - Extras: `FlatSVGIcon` now allows specifying icon width and height in

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

@@ -246,6 +246,27 @@ public interface FlatClientProperties
 	 */
 	String TABBED_PANE_HAS_FULL_BORDER = "JTabbedPane.hasFullBorder";
 
+	/**
+	 * Specifies the minimum width of a tab.
+	 * <p>
+	 * <strong>Component</strong> {@link javax.swing.JTabbedPane}<br>
+	 * or tab content components (see {@link javax.swing.JTabbedPane#setComponentAt(int, java.awt.Component)})<br>
+	 * <strong>Value type</strong> {@link java.lang.Integer}
+	 */
+	String TABBED_PANE_MINIMUM_TAB_WIDTH = "JTabbedPane.minimumTabWidth";
+
+	/**
+	 * Specifies the maximum width of a tab.
+	 * <p>
+	 * Applied only if tab does not have a custom tab component
+	 * (see {@link javax.swing.JTabbedPane#setTabComponentAt(int, java.awt.Component)}).
+	 * <p>
+	 * <strong>Component</strong> {@link javax.swing.JTabbedPane}<br>
+	 * or tab content components (see {@link javax.swing.JTabbedPane#setComponentAt(int, java.awt.Component)})<br>
+	 * <strong>Value type</strong> {@link java.lang.Integer}
+	 */
+	String TABBED_PANE_MAXIMUM_TAB_WIDTH = "JTabbedPane.maximumTabWidth";
+
 	/**
 	 * Specifies the height of a tab.
 	 * <p>

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

@@ -118,6 +118,8 @@ import com.formdev.flatlaf.util.UIScale;
  * @uiDefault TabbedPane.focusColor						Color
  * @uiDefault TabbedPane.tabSeparatorColor				Color	optional; defaults to TabbedPane.contentAreaColor
  * @uiDefault TabbedPane.contentAreaColor				Color
+ * @uiDefault TabbedPane.minimumTabWidth				int		optional
+ * @uiDefault TabbedPane.maximumTabWidth				int		optional
  * @uiDefault TabbedPane.tabHeight						int
  * @uiDefault TabbedPane.tabSelectionHeight				int
  * @uiDefault TabbedPane.contentSeparatorHeight			int
@@ -153,12 +155,15 @@ public class FlatTabbedPaneUI
 	protected Color contentAreaColor;
 
 	private int textIconGapUnscaled;
+	protected int minimumTabWidth;
+	protected int maximumTabWidth;
 	protected int tabHeight;
 	protected int tabSelectionHeight;
 	protected int contentSeparatorHeight;
 	protected boolean showTabSeparators;
 	protected boolean tabSeparatorsFullHeight;
 	protected boolean hasFullBorder;
+	protected boolean tabsOpaque = true;
 
 	private String hiddenTabsNavigationStr;
 	protected Icon closeIcon;
@@ -217,12 +222,15 @@ public class FlatTabbedPaneUI
 		contentAreaColor = UIManager.getColor( "TabbedPane.contentAreaColor" );
 
 		textIconGapUnscaled = UIManager.getInt( "TabbedPane.textIconGap" );
+		minimumTabWidth = UIManager.getInt( "TabbedPane.minimumTabWidth" );
+		maximumTabWidth = UIManager.getInt( "TabbedPane.maximumTabWidth" );
 		tabHeight = UIManager.getInt( "TabbedPane.tabHeight" );
 		tabSelectionHeight = UIManager.getInt( "TabbedPane.tabSelectionHeight" );
 		contentSeparatorHeight = UIManager.getInt( "TabbedPane.contentSeparatorHeight" );
 		showTabSeparators = UIManager.getBoolean( "TabbedPane.showTabSeparators" );
 		tabSeparatorsFullHeight = UIManager.getBoolean( "TabbedPane.tabSeparatorsFullHeight" );
 		hasFullBorder = UIManager.getBoolean( "TabbedPane.hasFullBorder" );
+		tabsOpaque = UIManager.getBoolean( "TabbedPane.tabsOpaque" );
 		hiddenTabsNavigationStr = UIManager.getString( "TabbedPane.hiddenTabsNavigation" );
 		closeIcon = UIManager.getIcon( "TabbedPane.closeIcon" );
 
@@ -518,8 +526,19 @@ public class FlatTabbedPaneUI
 		textIconGap = scale( textIconGapUnscaled );
 
 		int tabWidth = super.calculateTabWidth( tabPlacement, tabIndex, metrics ) - 3 /* was added by superclass */;
+
+		// make tab wider if closable
 		if( isTabClosable( tabIndex ) )
 			tabWidth += closeIcon.getIconWidth();
+
+		// apply minimum and maximum tab width
+		int min = getTabClientPropertyInt( tabIndex, TABBED_PANE_MINIMUM_TAB_WIDTH, minimumTabWidth );
+		int max = getTabClientPropertyInt( tabIndex, TABBED_PANE_MAXIMUM_TAB_WIDTH, maximumTabWidth );
+		if( min > 0 )
+			tabWidth = Math.max( tabWidth, scale( min ) );
+		if( max > 0 && tabPane.getTabComponentAt( tabIndex ) == null )
+			tabWidth = Math.min( tabWidth, scale( max ) );
+
 		return tabWidth;
 	}
 
@@ -649,6 +668,46 @@ public class FlatTabbedPaneUI
 			paintTabArea( g, tabPlacement, selectedIndex );
 	}
 
+	@Override
+	protected void paintTab( Graphics g, int tabPlacement, Rectangle[] rects,
+		int tabIndex, Rectangle iconRect, Rectangle textRect )
+	{
+		Rectangle tabRect = rects[tabIndex];
+		boolean isSelected = (tabIndex == tabPane.getSelectedIndex());
+
+		// paint background
+		if( tabsOpaque || tabPane.isOpaque() )
+			paintTabBackground( g, tabPlacement, tabIndex, tabRect.x, tabRect.y, tabRect.width, tabRect.height, isSelected );
+
+		// paint border
+		paintTabBorder( g, tabPlacement, tabIndex, tabRect.x, tabRect.y, tabRect.width, tabRect.height, isSelected );
+
+		if( tabPane.getTabComponentAt( tabIndex ) != null )
+			return;
+
+		// layout title and icon
+		String title = tabPane.getTitleAt( tabIndex );
+		Icon icon = getIconForTab( tabIndex );
+		Font font = tabPane.getFont();
+		FontMetrics metrics = tabPane.getFontMetrics( font );
+		String clippedTitle = layoutAndClipLabel( tabPlacement, metrics, tabIndex, title, icon, tabRect, iconRect, textRect, isSelected );
+
+		// special title clipping for scroll layout where title off last visible tab on right side may be truncated
+		if( tabViewport != null && (tabPlacement == TOP || tabPlacement == BOTTOM) ) {
+			Rectangle viewRect = tabViewport.getViewRect();
+			viewRect.width -= 4; // subtract width of cropped edge
+			if( !viewRect.contains( textRect ) ) {
+				Rectangle r = viewRect.intersection( textRect );
+				if( r.x > viewRect.x )
+					clippedTitle = JavaCompatibility.getClippedString( null, metrics, title, r.width );
+			}
+		}
+
+		// paint title and icon
+		paintText( g, tabPlacement, font, metrics, tabIndex, clippedTitle, textRect, isSelected );
+		paintIcon( g, tabPlacement, tabIndex, icon, iconRect, isSelected );
+	}
+
 	@Override
 	protected void paintText( Graphics g, int tabPlacement, Font font, FontMetrics metrics,
 		int tabIndex, String title, Rectangle textRect, boolean isSelected )
@@ -662,20 +721,6 @@ public class FlatTabbedPaneUI
 			return;
 		}
 
-		// clip title if our layout manager is used
-		// (normally this is done by invoker, but fails in this case)
-		if( tabViewport != null &&
-			(tabPlacement == TOP || tabPlacement == BOTTOM) )
-		{
-			Rectangle viewRect = tabViewport.getViewRect();
-			viewRect.width -= 4; // subtract width of cropped edge
-			if( !viewRect.contains( textRect ) ) {
-				Rectangle r = viewRect.intersection( textRect );
-				if( r.x > viewRect.x )
-					title = JavaCompatibility.getClippedString( null, metrics, title, r.width );
-			}
-		}
-
 		// plain text
 		Color color;
 		if( tabPane.isEnabled() && tabPane.isEnabledAt( tabIndex ) ) {
@@ -898,14 +943,37 @@ public class FlatTabbedPaneUI
 	{
 	}
 
-	@Override
+	protected String layoutAndClipLabel( int tabPlacement, FontMetrics metrics, int tabIndex,
-	protected void layoutLabel( int tabPlacement, FontMetrics metrics, int tabIndex, String title, Icon icon,
+		String title, Icon icon, Rectangle tabRect, Rectangle iconRect, Rectangle textRect, boolean isSelected )
-		Rectangle tabRect, Rectangle iconRect, Rectangle textRect, boolean isSelected )
 	{
-		// update textIconGap before used in super class
+		// remove tab insets and space for close button from the tab rectangle
-		textIconGap = scale( textIconGapUnscaled );
+		// to get correctly clipped title
+		tabRect = FlatUIUtils.subtractInsets( tabRect, getTabInsets( tabPlacement, tabIndex ) );
+		if( isTabClosable( tabIndex ) ) {
+			tabRect.width -= closeIcon.getIconWidth();
+			if( !isLeftToRight() )
+				tabRect.x += closeIcon.getIconWidth();
+		}
 
-		super.layoutLabel( tabPlacement, metrics, tabIndex, title, icon, tabRect, iconRect, textRect, isSelected );
+		// reset rectangles
+		textRect.setBounds( 0, 0, 0, 0 );
+		iconRect.setBounds( 0, 0, 0, 0 );
+
+		// temporary set "html" client property on tabbed pane, which is used by SwingUtilities.layoutCompoundLabel()
+		View view = getTextViewForTab( tabIndex );
+		if( view != null )
+			tabPane.putClientProperty( "html", view );
+
+		// layout label
+		String clippedTitle = SwingUtilities.layoutCompoundLabel( tabPane, metrics, title, icon,
+			SwingUtilities.CENTER, SwingUtilities.CENTER,
+			SwingUtilities.CENTER, SwingUtilities.TRAILING,
+			tabRect, iconRect, textRect, scale( textIconGapUnscaled ) );
+
+		// remove temporary client property
+		tabPane.putClientProperty( "html", null );
+
+		return clippedTitle;
 	}
 
 	@Override
@@ -993,6 +1061,11 @@ public class FlatTabbedPaneUI
 		return tabPane.getClientProperty( key );
 	}
 
+	protected int getTabClientPropertyInt( int tabIndex, String key, int defaultValue ) {
+		Object value = getTabClientProperty( tabIndex, key );
+		return (value instanceof Integer) ? (int) value : defaultValue;
+	}
+
 	protected void ensureCurrentLayout() {
 		// since super.ensureCurrentLayout() is private,
 		// use super.getTabRunCount() as workaround
@@ -1718,6 +1791,8 @@ public class FlatTabbedPaneUI
 				case TABBED_PANE_SHOW_TAB_SEPARATORS:
 				case TABBED_PANE_SHOW_CONTENT_SEPARATOR:
 				case TABBED_PANE_HAS_FULL_BORDER:
+				case TABBED_PANE_MINIMUM_TAB_WIDTH:
+				case TABBED_PANE_MAXIMUM_TAB_WIDTH:
 				case TABBED_PANE_TAB_HEIGHT:
 				case TABBED_PANE_TAB_INSETS:
 				case TABBED_PANE_HIDDEN_TABS_NAVIGATION:
@@ -1757,6 +1832,8 @@ public class FlatTabbedPaneUI
 
 		protected void contentPropertyChange( PropertyChangeEvent e ) {
 			switch( e.getPropertyName() ) {
+				case TABBED_PANE_MINIMUM_TAB_WIDTH:
+				case TABBED_PANE_MAXIMUM_TAB_WIDTH:
 				case TABBED_PANE_TAB_INSETS:
 				case TABBED_PANE_TAB_CLOSABLE:
 					tabPane.revalidate();

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

@@ -323,6 +323,16 @@ public class FlatContainerTest
 		}
 	}
 
+	private void minimumTabWidthChanged() {
+		Integer minimumTabWidth = minimumTabWidthCheckBox.isSelected() ? 100 : null;
+		putTabbedPanesClientProperty( TABBED_PANE_MINIMUM_TAB_WIDTH, minimumTabWidth );
+	}
+
+	private void maximumTabWidthChanged() {
+		Integer maximumTabWidth = maximumTabWidthCheckBox.isSelected() ? 60 : null;
+		putTabbedPanesClientProperty( TABBED_PANE_MAXIMUM_TAB_WIDTH, maximumTabWidth );
+	}
+
 	private void initComponents() {
 		// JFormDesigner - Component initialization - DO NOT MODIFY  //GEN-BEGIN:initComponents
 		JPanel panel9 = new JPanel();
@@ -365,6 +375,8 @@ public class FlatContainerTest
 		trailingComponentCheckBox = new JCheckBox();
 		showTabSeparatorsCheckBox = new JCheckBox();
 		secondTabWiderCheckBox = new JCheckBox();
+		minimumTabWidthCheckBox = new JCheckBox();
+		maximumTabWidthCheckBox = new JCheckBox();
 		CellConstraints cc = new CellConstraints();
 
 		//======== this ========
@@ -480,6 +492,8 @@ public class FlatContainerTest
 					"[]" +
 					"[]para" +
 					"[]" +
+					"[]para" +
+					"[]" +
 					"[]"));
 
 				//---- tabScrollCheckBox ----
@@ -605,6 +619,16 @@ public class FlatContainerTest
 				secondTabWiderCheckBox.setText("Second Tab insets wider (4,20,4,20)");
 				secondTabWiderCheckBox.addActionListener(e -> secondTabWiderChanged());
 				tabbedPaneControlPanel.add(secondTabWiderCheckBox, "cell 2 6");
+
+				//---- minimumTabWidthCheckBox ----
+				minimumTabWidthCheckBox.setText("Minimum tab width (100)");
+				minimumTabWidthCheckBox.addActionListener(e -> minimumTabWidthChanged());
+				tabbedPaneControlPanel.add(minimumTabWidthCheckBox, "cell 2 7");
+
+				//---- maximumTabWidthCheckBox ----
+				maximumTabWidthCheckBox.setText("Maximum tab width (60)");
+				maximumTabWidthCheckBox.addActionListener(e -> maximumTabWidthChanged());
+				tabbedPaneControlPanel.add(maximumTabWidthCheckBox, "cell 2 8");
 			}
 			panel9.add(tabbedPaneControlPanel, cc.xywh(1, 11, 3, 1));
 		}
@@ -637,6 +661,8 @@ public class FlatContainerTest
 	private JCheckBox trailingComponentCheckBox;
 	private JCheckBox showTabSeparatorsCheckBox;
 	private JCheckBox secondTabWiderCheckBox;
+	private JCheckBox minimumTabWidthCheckBox;
+	private JCheckBox maximumTabWidthCheckBox;
 	// 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( "com.formdev.flatlaf.testing.FlatTestFrame$NoRightToLeftPanel", new FormLayoutManager( class net.miginfocom.swing.MigLayout ) {
 					"$layoutConstraints": "insets 0,hidemode 3"
 					"$columnConstraints": "[][fill][]"
-					"$rowConstraints": "[center][][]para[][]para[][]"
+					"$rowConstraints": "[center][][]para[][]para[][]para[][]"
 				} ) {
 					name: "tabbedPaneControlPanel"
 					"opaque": false
@@ -381,6 +381,26 @@ new FormModel {
 					}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
 						"value": "cell 2 6"
 					} )
+					add( new FormComponent( "javax.swing.JCheckBox" ) {
+						name: "minimumTabWidthCheckBox"
+						"text": "Minimum tab width (100)"
+						auxiliary() {
+							"JavaCodeGenerator.variableLocal": false
+						}
+						addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "minimumTabWidthChanged", false ) )
+					}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+						"value": "cell 2 7"
+					} )
+					add( new FormComponent( "javax.swing.JCheckBox" ) {
+						name: "maximumTabWidthCheckBox"
+						"text": "Maximum tab width (60)"
+						auxiliary() {
+							"JavaCodeGenerator.variableLocal": false
+						}
+						addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "maximumTabWidthChanged", false ) )
+					}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+						"value": "cell 2 8"
+					} )
 				}, new FormLayoutConstraints( class com.jgoodies.forms.layout.CellConstraints ) {
 					"gridY": 11
 					"gridWidth": 3