TabbedPane: support rotated/vertical tabs (issue #633)

CHANGELOG.md

@@ -5,6 +5,7 @@ FlatLaf Change Log
 
 #### New features and improvements
 
+- TabbedPane: Support vertical tabs. (PR #758, issue #633)
 - ToolBar: Added styling properties `separatorWidth` and `separatorColor`.
 
 #### Fixed bugs

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

@@ -932,6 +932,59 @@ public interface FlatClientProperties
 	 */
 	String TABBED_PANE_TAB_ICON_PLACEMENT = "JTabbedPane.tabIconPlacement";
 
+	/**
+	 * Specifies the rotation of the tabs (title, icon, etc).
+	 * <p>
+	 * <strong>Component</strong> {@link javax.swing.JTabbedPane}<br>
+	 * <strong>Value type</strong> {@link java.lang.Integer} or {@link java.lang.String}<br>
+	 * <strong>Allowed Values</strong>
+	 *     {@link SwingConstants#LEFT},
+	 *     {@link SwingConstants#RIGHT},
+	 *     {@link #TABBED_PANE_TAB_ROTATION_NONE}, (default)
+	 *     {@link #TABBED_PANE_TAB_ROTATION_AUTO},
+	 *     {@link #TABBED_PANE_TAB_ROTATION_LEFT} or
+	 *     {@link #TABBED_PANE_TAB_ROTATION_RIGHT}
+	 *
+	 * @since 3.3
+	 */
+	String TABBED_PANE_TAB_ROTATION = "JTabbedPane.tabRotation";
+
+	/**
+	 * Tabs are not rotated.
+	 *
+	 * @see #TABBED_PANE_TAB_ROTATION
+	 * @since 3.3
+	 */
+	String TABBED_PANE_TAB_ROTATION_NONE = "none";
+
+	/**
+	 * Tabs are rotated depending on tab placement.
+	 * <p>
+	 * For top and bottom tab placement, the tabs are not rotated.<br>
+	 * For left tab placement, the tabs are rotated counter clockwise.<br>
+	 * For right tab placement, the tabs are rotated clockwise.
+	 *
+	 * @see #TABBED_PANE_TAB_ROTATION
+	 * @since 3.3
+	 */
+	String TABBED_PANE_TAB_ROTATION_AUTO = "auto";
+
+	/**
+	 * Tabs are rotated counter clockwise.
+	 *
+	 * @see #TABBED_PANE_TAB_ROTATION
+	 * @since 3.3
+	 */
+	String TABBED_PANE_TAB_ROTATION_LEFT = "left";
+
+	/**
+	 * Tabs are rotated clockwise.
+	 *
+	 * @see #TABBED_PANE_TAB_ROTATION
+	 * @since 3.3
+	 */
+	String TABBED_PANE_TAB_ROTATION_RIGHT = "right";
+
 	/**
 	 * Specifies a component that will be placed at the leading edge of the tabs area.
 	 * <p>