animated Laf changing added to flatlaf-extras, used in Demo

CHANGELOG.md

@@ -3,6 +3,7 @@ FlatLaf Change Log
 
 ## Unreleased
 
+- Animated theme change (see [FlatLaf Extras](flatlaf-extras)).
 - Custom window decorations: Fixed maximized window bounds when programmatically
   maximizing window. E.g. restoring window state at startup. (issue #129)
 - InternalFrame: Title pane height was too small when iconify, maximize and close

flatlaf-core/src/main/java/com/formdev/flatlaf/util/Animator.java

@@ -92,6 +92,7 @@ public class Animator
 	/**
 	 * Sets the resolution of the animation in milliseconds.
 	 *
+	 * @param resolution the resolution of the animation in milliseconds
 	 * @throws IllegalStateException if animation is running
 	 * @throws IllegalArgumentException if resolution is <= zero
 	 */

flatlaf-demo/src/main/java/com/formdev/flatlaf/demo/ControlBar.java

@@ -27,6 +27,7 @@ import javax.swing.UIManager.LookAndFeelInfo;
 import javax.swing.plaf.metal.MetalLookAndFeel;
 import javax.swing.plaf.nimbus.NimbusLookAndFeel;
 import com.formdev.flatlaf.*;
+import com.formdev.flatlaf.extras.FlatAnimatedLafChange;
 import com.formdev.flatlaf.util.SystemInfo;
 import com.formdev.flatlaf.util.UIScale;
 import net.miginfocom.swing.*;
@@ -193,6 +194,8 @@ class ControlBar
 
 		EventQueue.invokeLater( () -> {
 			try {
+				FlatAnimatedLafChange.showSnapshot();
+
 				// change look and feel
 				UIManager.setLookAndFeel( lafClassName );
 
@@ -202,6 +205,7 @@ class ControlBar
 
 				// update all components
 				FlatLaf.updateUI();
+				FlatAnimatedLafChange.hideSnapshotWithAnimation();
 
 				// increase size of frame if necessary
 				int width = frame.getWidth();

flatlaf-demo/src/main/java/com/formdev/flatlaf/demo/DemoFrame.java

@@ -27,6 +27,7 @@ import com.formdev.flatlaf.FlatClientProperties;
 import com.formdev.flatlaf.FlatLaf;
 import com.formdev.flatlaf.demo.extras.*;
 import com.formdev.flatlaf.demo.intellijthemes.*;
+import com.formdev.flatlaf.extras.FlatAnimatedLafChange;
 import com.formdev.flatlaf.extras.FlatSVGIcon;
 import com.formdev.flatlaf.extras.SVGUtils;
 import com.formdev.flatlaf.ui.JBRCustomDecorations;
@@ -105,14 +106,21 @@ class DemoFrame
 		repaint();
 	}
 
+	private void animatedLafChangeChanged() {
+		System.setProperty( "flatlaf.animatedLafChange", String.valueOf( animatedLafChangeMenuItem.isSelected() ) );
+	}
+
 	private void fontFamilyChanged( ActionEvent e ) {
 		String fontFamily = e.getActionCommand();
 
+		FlatAnimatedLafChange.showSnapshot();
+
 		Font font = UIManager.getFont( "defaultFont" );
 		Font newFont = StyleContext.getDefaultStyleContext().getFont( fontFamily, font.getStyle(), font.getSize() );
 		UIManager.put( "defaultFont", newFont );
 
 		FlatLaf.updateUI();
+		FlatAnimatedLafChange.hideSnapshotWithAnimation();
 	}
 
 	private void fontSizeChanged( ActionEvent e ) {
@@ -248,6 +256,7 @@ class DemoFrame
 		menuBarEmbeddedCheckBoxMenuItem = new JCheckBoxMenuItem();
 		underlineMenuSelectionMenuItem = new JCheckBoxMenuItem();
 		alwaysShowMnemonicsMenuItem = new JCheckBoxMenuItem();
+		animatedLafChangeMenuItem = new JCheckBoxMenuItem();
 		JMenu helpMenu = new JMenu();
 		JMenuItem aboutMenuItem = new JMenuItem();
 		JToolBar toolBar1 = new JToolBar();
@@ -501,6 +510,12 @@ class DemoFrame
 				alwaysShowMnemonicsMenuItem.setText("Always show mnemonics");
 				alwaysShowMnemonicsMenuItem.addActionListener(e -> alwaysShowMnemonics());
 				optionsMenu.add(alwaysShowMnemonicsMenuItem);
+
+				//---- animatedLafChangeMenuItem ----
+				animatedLafChangeMenuItem.setText("Animated Laf Change");
+				animatedLafChangeMenuItem.setSelected(true);
+				animatedLafChangeMenuItem.addActionListener(e -> animatedLafChangeChanged());
+				optionsMenu.add(animatedLafChangeMenuItem);
 			}
 			menuBar1.add(optionsMenu);
 
@@ -620,6 +635,7 @@ class DemoFrame
 	private JCheckBoxMenuItem menuBarEmbeddedCheckBoxMenuItem;
 	private JCheckBoxMenuItem underlineMenuSelectionMenuItem;
 	private JCheckBoxMenuItem alwaysShowMnemonicsMenuItem;
+	private JCheckBoxMenuItem animatedLafChangeMenuItem;
 	private JTabbedPane tabbedPane;
 	private ControlBar controlBar;
 	// JFormDesigner - End of variables declaration  //GEN-END:variables

flatlaf-demo/src/main/java/com/formdev/flatlaf/demo/DemoFrame.jfd

@@ -1,4 +1,4 @@
-JFDML JFormDesigner: "7.0.1.0.272" Java: "13.0.2" encoding: "UTF-8"
+JFDML JFormDesigner: "7.0.2.0.298" Java: "14.0.2" encoding: "UTF-8"
 
 new FormModel {
 	contentType: "form/swing"
@@ -356,6 +356,15 @@ new FormModel {
 						}
 						addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "alwaysShowMnemonics", false ) )
 					} )
+					add( new FormComponent( "javax.swing.JCheckBoxMenuItem" ) {
+						name: "animatedLafChangeMenuItem"
+						"text": "Animated Laf Change"
+						"selected": true
+						auxiliary() {
+							"JavaCodeGenerator.variableLocal": false
+						}
+						addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "animatedLafChangeChanged", false ) )
+					} )
 				} )
 				add( new FormContainer( "javax.swing.JMenu", new FormLayoutManager( class javax.swing.JMenu ) ) {
 					name: "helpMenu"

flatlaf-demo/src/main/java/com/formdev/flatlaf/demo/intellijthemes/IJThemesPanel.java

@@ -49,6 +49,7 @@ import com.formdev.flatlaf.FlatLightLaf;
 import com.formdev.flatlaf.FlatPropertiesLaf;
 import com.formdev.flatlaf.IntelliJTheme;
 import com.formdev.flatlaf.demo.DemoPrefs;
+import com.formdev.flatlaf.extras.FlatAnimatedLafChange;
 import com.formdev.flatlaf.extras.FlatSVGIcon;
 import com.formdev.flatlaf.util.StringUtils;
 import net.miginfocom.swing.*;
@@ -219,6 +220,8 @@ public class IJThemesPanel
 			if( themeInfo.lafClassName.equals( UIManager.getLookAndFeel().getClass().getName() ) )
 				return;
 
+			FlatAnimatedLafChange.showSnapshot();
+
 			try {
 				UIManager.setLookAndFeel( themeInfo.lafClassName );
 			} catch( Exception ex ) {
@@ -226,6 +229,8 @@ public class IJThemesPanel
 				showInformationDialog( "Failed to create '" + themeInfo.lafClassName + "'.", ex );
 			}
 		} else if( themeInfo.themeFile != null ) {
+			FlatAnimatedLafChange.showSnapshot();
+
 			try {
 				if( themeInfo.themeFile.getName().endsWith( ".properties" ) ) {
 				    FlatLaf.install( new FlatPropertiesLaf( themeInfo.name, themeInfo.themeFile ) );
@@ -238,12 +243,15 @@ public class IJThemesPanel
 				showInformationDialog( "Failed to load '" + themeInfo.themeFile + "'.", ex );
 			}
 		} else {
+			FlatAnimatedLafChange.showSnapshot();
+
 			IntelliJTheme.install( getClass().getResourceAsStream( THEMES_PACKAGE + themeInfo.resourceName ) );
 		    DemoPrefs.getState().put( DemoPrefs.KEY_LAF_THEME, DemoPrefs.RESOURCE_PREFIX + themeInfo.resourceName );
 		}
 
 		// update all components
 		FlatLaf.updateUI();
+		FlatAnimatedLafChange.hideSnapshotWithAnimation();
 	}
 
 	private void saveTheme() {

flatlaf-extras/README.md

@@ -3,6 +3,8 @@ FlatLaf Extras
 
 This sub-project provides some additional components and classes:
 
+- [FlatAnimatedLafChange](src/main/java/com/formdev/flatlaf/extras/FlatAnimatedLafChange.java):
+  Animated Laf changing.
 - [FlatInspector](src/main/java/com/formdev/flatlaf/extras/FlatInspector.java):
   A simple UI inspector that shows information about UI component at mouse
   location in a tooltip.

flatlaf-extras/src/main/java/com/formdev/flatlaf/extras/FlatAnimatedLafChange.java

@@ -0,0 +1,163 @@
+/*
+ * Copyright 2020 FormDev Software GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.formdev.flatlaf.extras;
+
+import java.awt.AlphaComposite;
+import java.awt.Graphics;
+import java.awt.Graphics2D;
+import java.awt.Image;
+import java.awt.Window;
+import java.util.HashMap;
+import java.util.Map;
+import javax.swing.JComponent;
+import javax.swing.JLayeredPane;
+import javax.swing.RootPaneContainer;
+import com.formdev.flatlaf.FlatSystemProperties;
+import com.formdev.flatlaf.util.Animator;
+
+/**
+ * Animated look and feel changing.
+ * <p>
+ * Invoke {@link #showSnapshot()} before setting look and feel and
+ * {@link #hideSnapshotWithAnimation()} after updating UI. E.g.
+ * <pre>
+ * FlatAnimatedLafChange.showSnapshot();
+ * UIManager.setLookAndFeel( lafClassName );
+ * FlatLaf.updateUI();
+ * FlatAnimatedLafChange.hideSnapshotWithAnimation();
+ * </pre>
+ *
+ * @author Karl Tauber
+ */
+public class FlatAnimatedLafChange
+{
+	/**
+	 * The duration of the animation in milliseconds. Default is 160 ms.
+	 */
+	public static int duration = 160;
+
+	/**
+	 * The resolution of the animation in milliseconds. Default is 40 ms.
+	 */
+	public static int resolution = 40;
+
+	private static Animator animator;
+	private static final Map<JLayeredPane, JComponent> map = new HashMap<>();
+	private static float alpha;
+
+	/**
+	 * Create a snapshot of the old UI and shows it on top of the UI.
+	 * Invoke before setting new look and feel.
+	 */
+	public static void showSnapshot() {
+		if( !FlatSystemProperties.getBoolean( "flatlaf.animatedLafChange", true ) )
+			return;
+
+		// stop already running animation
+		if( animator != null )
+			animator.stop();
+
+		alpha = 1;
+
+		// create snapshots for all shown windows
+		Window[] windows = Window.getWindows();
+		for( Window window : windows ) {
+			if( !(window instanceof RootPaneContainer) || !window.isShowing() )
+				continue;
+
+			JLayeredPane layeredPane = ((RootPaneContainer)window).getLayeredPane();
+
+			// create snapshot image of layered pane
+			Image snapshot = window.createImage( window.getWidth(), window.getHeight() );
+			layeredPane.paint( snapshot.getGraphics() );
+
+			// create snapshot layer, which is added to layered pane and paints
+			// snapshot with animated alpha
+			JComponent snapshotLayer = new JComponent() {
+				@Override
+				public void paint( Graphics g ) {
+					((Graphics2D)g).setComposite( AlphaComposite.getInstance( AlphaComposite.SRC_OVER, alpha ) );
+					g.drawImage( snapshot, 0, 0, null );
+				}
+			};
+			snapshotLayer.setSize( layeredPane.getSize() );
+
+			// add image layer to layered pane
+			layeredPane.add( snapshotLayer, JLayeredPane.DRAG_LAYER );
+			map.put( layeredPane, snapshotLayer );
+		}
+	}
+
+	/**
+	 * Starts an animation that shows the snapshot (created by {@link #showSnapshot()}
+	 * with an decreasing alpha. At the end, the snapshot is removed and the new UI is shown.
+	 * Invoke after updating UI.
+	 */
+	public static void hideSnapshotWithAnimation() {
+		if( !FlatSystemProperties.getBoolean( "flatlaf.animatedLafChange", true ) )
+			return;
+
+		if( map.isEmpty() )
+			return;
+
+		// create animator
+		animator = new Animator( duration, new Animator.TimingTarget() {
+			@Override
+			public void timingEvent( float fraction ) {
+				if( fraction < 0.1 || fraction > 0.9 )
+					return; // ignore initial and last events
+
+				alpha = 1f - fraction;
+
+				// repaint snapshots
+				for( Map.Entry<JLayeredPane, JComponent> e : map.entrySet() ) {
+					if( e.getKey().isShowing() )
+						e.getValue().repaint();
+				}
+			}
+
+			@Override
+			public void end() {
+				hideSnapshot();
+				animator = null;
+			}
+		} );
+
+		animator.setResolution( resolution );
+		animator.start();
+	}
+
+	private static void hideSnapshot() {
+		// remove snapshots
+		for( Map.Entry<JLayeredPane, JComponent> e : map.entrySet() ) {
+			e.getKey().remove( e.getValue() );
+			e.getKey().repaint();
+		}
+
+		map.clear();
+	}
+
+	/**
+	 * Stops a running animation (if any) and hides the snapshot.
+	 */
+	public static void stop() {
+		if( animator != null )
+			animator.stop();
+		else
+			hideSnapshot();
+	}
+}

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

@@ -73,6 +73,9 @@ public class FlatTestFrame
 				System.setProperty( FlatSystemProperties.UI_SCALE, scaleFactor );
 		}
 
+		// disable animated Laf change
+		System.setProperty( "flatlaf.animatedLafChange", "false" );
+
 		// set look and feel
 		DemoPrefs.initLaf( args );