Allow hiding the title of a window using a rootPane property

macos/src/main/java/com/github/weisj/darklaf/platform/macos/ui/MacOSDecorationsUtil.java

@@ -58,7 +58,7 @@ public final class MacOSDecorationsUtil {
         setFullSizeContent(windowHandle, useColoredTitleBar);
 
         boolean titleVisible = SystemInfo.isMacOSMojave && !UIManager.getBoolean("Theme.macos.useSwingTitleLabel");
-        JNIDecorationsMacOS.setTitleEnabled(windowHandle, titleVisible);
+        setTitleVisible(windowHandle, titleVisible);
         if (titleVisible) {
             boolean isDarkTheme = UIManager.getBoolean("Theme.dark");
             JNIDecorationsMacOS.setDarkTheme(windowHandle, isDarkTheme);
@@ -88,7 +88,7 @@ public final class MacOSDecorationsUtil {
                     isTransparentTitleBarEnabled(information.rootPane));
             window.setBounds(bounds);
         }
-        JNIDecorationsMacOS.setTitleEnabled(information.windowHandle, true);
+        setTitleVisible(information, true);
         JNIDecorationsMacOS.releaseWindow(information.windowHandle);
     }
 
@@ -99,4 +99,12 @@ public final class MacOSDecorationsUtil {
     static boolean isTransparentTitleBarEnabled(final JRootPane rootPane) {
         return PropertyUtil.getBooleanProperty(rootPane, TRANSPARENT_TITLE_BAR_KEY);
     }
+
+    static void setTitleVisible(final DecorationInformation decorationInformation, final boolean visible) {
+        setTitleVisible(decorationInformation.windowHandle, visible);
+    }
+
+    private static void setTitleVisible(final long windowHandle, boolean visible) {
+        JNIDecorationsMacOS.setTitleEnabled(windowHandle, visible);
+    }
 }

macos/src/main/java/com/github/weisj/darklaf/platform/macos/ui/MacOSTitlePane.java

@@ -61,6 +61,7 @@ public class MacOSTitlePane extends CustomTitlePane {
         this.window = window;
         determineColors();
         updateTitleBarVisibility();
+        updateTitleVisibility();
         updateOpacity();
     }
 
@@ -102,7 +103,7 @@ public class MacOSTitlePane extends CustomTitlePane {
     @Override
     public void paintComponent(final Graphics g) {
         if (!isOpaque()) return;
-        
+
         int width = getWidth();
         int height = getHeight();
 
@@ -209,6 +210,8 @@ public class MacOSTitlePane extends CustomTitlePane {
             } else if (MacOSDecorationsUtil.TRANSPARENT_TITLE_BAR_KEY.equals(evt.getPropertyName())) {
                 updateOpacity();
                 repaint();
+            } else if (DecorationsConstants.KEY_HIDE_TITLE.equals(evt.getPropertyName())) {
+                updateTitleVisibility();
             }
         }
     }
@@ -258,6 +261,17 @@ public class MacOSTitlePane extends CustomTitlePane {
         rootPane.repaint();
     }
 
+    private void updateTitleVisibility() {
+        boolean visible = PropertyUtil.getBooleanProperty(rootPane, DecorationsConstants.KEY_HIDE_TITLE);
+        if (titleLabel != null) {
+            titleLabel.setVisible(visible);
+            doLayout();
+            repaint();
+        } else {
+            MacOSDecorationsUtil.setTitleVisible(decorationInformation, visible);
+        }
+    }
+
     private void updateOpacity() {
         setOpaque(!PropertyUtil.getBooleanProperty(rootPane, MacOSDecorationsUtil.TRANSPARENT_TITLE_BAR_KEY));
     }

platform-base/src/main/java/com/github/weisj/darklaf/platform/DecorationsConstants.java

@@ -27,4 +27,5 @@ public interface DecorationsConstants {
     String KEY_NO_DECORATIONS = "JRootPane.noDecorations";
     String KEY_UNIFIED_MENUBAR = "JRootPane.unifiedMenuBar";
     String KEY_COLORED_TITLE_BAR = "JRootPane.coloredTitleBar";
+    String KEY_HIDE_TITLE = "JRootPane.hideTitle";
 }

windows/src/main/java/com/github/weisj/darklaf/platform/windows/ui/WindowsTitlePane.java

@@ -124,6 +124,7 @@ public class WindowsTitlePane extends CustomTitlePane {
         installSubcomponents();
         menuBarStealer.install();
         updateTitleBarVisibility();
+        updateTitleVisibility();
         installDefaults();
         setLayout(createLayout());
         setOpaque(true);
@@ -135,6 +136,12 @@ public class WindowsTitlePane extends CustomTitlePane {
         rootPane.repaint();
     }
 
+    private void updateTitleVisibility() {
+        titleLabel.setVisible(!PropertyUtil.getBooleanProperty(rootPane, DecorationsConstants.KEY_HIDE_TITLE));
+        doLayout();
+        repaint();
+    }
+
     private TitleBarButton createButton(final Icon icon, final Action action) {
         return createButton(icon, action, false);
     }
@@ -953,6 +960,8 @@ public class WindowsTitlePane extends CustomTitlePane {
                 menuBarStealer.updateMenuBar(true);
             } else if (DecorationsConstants.KEY_HIDE_TITLEBAR.equals(evt.getPropertyName())) {
                 updateTitleBarVisibility();
+            } else if (DecorationsConstants.KEY_HIDE_TITLE.equals(evt.getPropertyName())) {
+                updateTitleVisibility();
             }
         }
     }