Accent color:

- Demo: added accent color switching to toolbar
- added `FlatLaf.setGlobalExtraDefaults()` for easy setting accent color at runtime

(issue #233)

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

@@ -86,6 +86,7 @@ public abstract class FlatLaf
 	private static final String DESKTOPFONTHINTS = "awt.font.desktophints";
 
 	private static List<Object> customDefaultsSources;
+	private static Map<String, String> globalExtraDefaults;
 	private Map<String, String> extraDefaults;
 
 	private String desktopPropertyName;
@@ -465,11 +466,14 @@ public abstract class FlatLaf
 	}
 
 	protected Properties getAdditionalDefaults() {
-		if( extraDefaults == null )
+		if( globalExtraDefaults == null && extraDefaults == null )
 			return null;
 
 		Properties properties = new Properties();
-		properties.putAll( extraDefaults );
+		if( globalExtraDefaults != null )
+			properties.putAll( globalExtraDefaults );
+		if( extraDefaults != null )
+			properties.putAll( extraDefaults );
 		return properties;
 	}
 
@@ -785,6 +789,38 @@ public abstract class FlatLaf
 		customDefaultsSources.remove( folder );
 	}
 
+	/**
+	 * Gets global extra UI defaults; or {@code null}.
+	 *
+	 * @since 1.6
+	 */
+	public static Map<String, String> getGlobalExtraDefaults() {
+		return globalExtraDefaults;
+	}
+
+	/**
+	 * Sets global extra UI defaults, which are only used when setting up the application look and feel.
+	 * E.g. using {@link UIManager#setLookAndFeel(LookAndFeel)} or {@link #setup(LookAndFeel)}.
+	 * <p>
+	 * The global extra defaults are useful for smaller additional defaults that may change.
+	 * E.g. accent color. Otherwise FlatLaf properties files should be used.
+	 * See {@link #registerCustomDefaultsSource(String)}.
+	 * <p>
+	 * The keys and values are strings in same format as in FlatLaf properties files.
+	 * <p>
+	 * Sample that setups "FlatLaf Light" theme with red accent color:
+	 * <pre>{@code
+	 * FlatLaf.setGlobalExtraDefaults( Collections.singletonMap( "@accentColor", "#f00" ) );
+	 * FlatLightLaf.setup();
+	 * }</pre>
+	 *
+	 * @see #setExtraDefaults(Map)
+	 * @since 1.6
+	 */
+	public static void setGlobalExtraDefaults( Map<String, String> globalExtraDefaults ) {
+		FlatLaf.globalExtraDefaults = globalExtraDefaults;
+	}
+
 	/**
 	 * Gets extra UI defaults; or {@code null}.
 	 *
@@ -811,6 +847,7 @@ public abstract class FlatLaf
 	 * FlatLaf.setup( laf );
 	 * }</pre>
 	 *
+	 * @see #setGlobalExtraDefaults(Map)
 	 * @since 1.6
 	 */
 	public void setExtraDefaults( Map<String, String> extraDefaults ) {

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

@@ -49,6 +49,9 @@ public class ColorFunctions
 
 	/**
 	 * Returns a color that is a mixture of two colors.
+	 * <p>
+	 * This can be used to animate a color change from {@code color1} to {@code color2}
+	 * by invoking this method multiple times with growing {@code weight} (from 0 to 1).
 	 *
 	 * @param color1 first color
 	 * @param color2 second color
@@ -79,6 +82,34 @@ public class ColorFunctions
 			Math.round( a2 + ((a1 - a2) * weight) ) );
 	}
 
+	/**
+	 * Mix color with white, which makes the color brighter.
+	 * This is the same as {@link #mix}{@code (Color.white, color, weight)}.
+	 *
+	 * @param color second color
+	 * @param weight the weight (in range 0-1) to mix the two colors.
+	 *               Larger weight uses more of first color, smaller weight more of second color.
+	 * @return mixture of colors
+	 * @since 1.6
+	 */
+	public static Color tint( Color color, float weight ) {
+		return mix( Color.white, color, weight );
+	}
+
+	/**
+	 * Mix color with black, which makes the color darker.
+	 * This is the same as {@link #mix}{@code (Color.black, color, weight)}.
+	 *
+	 * @param color second color
+	 * @param weight the weight (in range 0-1) to mix the two colors.
+	 *               Larger weight uses more of first color, smaller weight more of second color.
+	 * @return mixture of colors
+	 * @since 1.6
+	 */
+	public static Color shade( Color color, float weight ) {
+		return mix( Color.black, color, weight );
+	}
+
 	/**
 	 * Calculates the luma (perceptual brightness) of the given color.
 	 * <p>

flatlaf-core/src/main/resources/com/formdev/flatlaf/FlatIntelliJLaf.properties

@@ -41,7 +41,7 @@
 Button.focusedBackground = null
 
 Button.default.background = @accentButtonDefaultBackground
-Button.default.foreground = #fff
+Button.default.foreground = contrast($Button.default.background,lighten(@foreground,50%),#fff,50%)
 Button.default.focusedBackground = null
 Button.default.borderColor = shade($Button.default.background,15%)
 Button.default.hoverBorderColor = tint($Button.default.background,50%)

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

@@ -24,11 +24,16 @@ import java.net.URISyntaxException;
 import java.time.Year;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.prefs.Preferences;
 import javax.swing.*;
 import javax.swing.text.DefaultEditorKit;
 import javax.swing.text.StyleContext;
+import com.formdev.flatlaf.FlatDarculaLaf;
+import com.formdev.flatlaf.FlatDarkLaf;
+import com.formdev.flatlaf.FlatIntelliJLaf;
 import com.formdev.flatlaf.FlatLaf;
+import com.formdev.flatlaf.FlatLightLaf;
 import com.formdev.flatlaf.demo.HintManager.Hint;
 import com.formdev.flatlaf.demo.extras.*;
 import com.formdev.flatlaf.demo.intellijthemes.*;
@@ -37,9 +42,12 @@ import com.formdev.flatlaf.extras.FlatSVGIcon;
 import com.formdev.flatlaf.extras.FlatUIDefaultsInspector;
 import com.formdev.flatlaf.extras.components.FlatButton;
 import com.formdev.flatlaf.extras.components.FlatButton.ButtonType;
+import com.formdev.flatlaf.icons.FlatAbstractIcon;
 import com.formdev.flatlaf.extras.FlatSVGUtils;
 import com.formdev.flatlaf.ui.FlatUIUtils;
 import com.formdev.flatlaf.ui.JBRCustomDecorations;
+import com.formdev.flatlaf.util.ColorFunctions;
+import com.formdev.flatlaf.util.LoggingFacade;
 import com.formdev.flatlaf.util.SystemInfo;
 import com.formdev.flatlaf.util.UIScale;
 import net.miginfocom.layout.ConstraintParser;
@@ -65,6 +73,7 @@ class DemoFrame
 
 		initComponents();
 		updateFontMenuItems();
+		initAccentColors();
 		controlBar.initialize( this, tabbedPane );
 
 		setIconImages( FlatSVGUtils.createWindowIconImages( "/com/formdev/flatlaf/demo/FlatLaf.svg" ) );
@@ -323,6 +332,74 @@ class DemoFrame
 			item.setEnabled( enabled );
 	}
 
+	// the real colors are defined in
+	// flatlaf-demo/src/main/resources/com/formdev/flatlaf/demo/FlatLightLaf.properties and
+	// flatlaf-demo/src/main/resources/com/formdev/flatlaf/demo/FlatDarkLaf.properties
+	private static String[] accentColorKeys = {
+		"Demo.accent.blue", "Demo.accent.purple", "Demo.accent.red",
+		"Demo.accent.orange", "Demo.accent.yellow", "Demo.accent.green",
+	};
+	private final JToggleButton[] accentColorButtons = new JToggleButton[accentColorKeys.length];
+	private JLabel accentColorLabel;
+
+	private void initAccentColors() {
+		accentColorLabel = new JLabel( "Accent color:" );
+
+		toolBar.add( Box.createHorizontalGlue() );
+		toolBar.add( accentColorLabel );
+
+		ButtonGroup group = new ButtonGroup();
+		for( int i = 0; i < accentColorButtons.length; i++ ) {
+			accentColorButtons[i] = new JToggleButton( new AccentColorIcon( accentColorKeys[i] ) );
+			accentColorButtons[i].addActionListener( this::accentColorChanged );
+			toolBar.add( accentColorButtons[i] );
+			group.add( accentColorButtons[i] );
+		}
+
+		accentColorButtons[0].setSelected( true );
+
+		UIManager.addPropertyChangeListener( e -> {
+			if( "lookAndFeel".equals( e.getPropertyName() ) )
+				updateAccentColorButtons();
+		} );
+		updateAccentColorButtons();
+	}
+
+	private void accentColorChanged( ActionEvent e ) {
+		String accentColor = accentColorKeys[0];
+		for( int i = 0; i < accentColorButtons.length; i++ ) {
+			if( accentColorButtons[i].isSelected() ) {
+				accentColor = accentColorKeys[i];
+				break;
+			}
+		}
+
+		FlatLaf.setGlobalExtraDefaults( (accentColor != accentColorKeys[0])
+			? Collections.singletonMap( "@accentColor", "$" + accentColor )
+			: null );
+
+		Class<? extends LookAndFeel> lafClass = UIManager.getLookAndFeel().getClass();
+		try {
+			FlatLaf.setup( lafClass.newInstance() );
+			FlatLaf.updateUI();
+		} catch( InstantiationException | IllegalAccessException ex ) {
+			LoggingFacade.INSTANCE.logSevere( null, ex );
+		}
+	}
+
+	private void updateAccentColorButtons() {
+		Class<? extends LookAndFeel> lafClass = UIManager.getLookAndFeel().getClass();
+		boolean isAccentColorSupported =
+			lafClass == FlatLightLaf.class ||
+			lafClass == FlatDarkLaf.class ||
+			lafClass == FlatIntelliJLaf.class ||
+			lafClass == FlatDarculaLaf.class;
+
+		accentColorLabel.setEnabled( isAccentColorSupported );
+		for( int i = 0; i < accentColorButtons.length; i++ )
+			accentColorButtons[i].setEnabled( isAccentColorSupported );
+	}
+
 	private void initComponents() {
 		// JFormDesigner - Component initialization - DO NOT MODIFY  //GEN-BEGIN:initComponents
 		JMenuBar menuBar1 = new JMenuBar();
@@ -369,7 +446,7 @@ class DemoFrame
 		JMenuItem showUIDefaultsInspectorMenuItem = new JMenuItem();
 		JMenu helpMenu = new JMenu();
 		JMenuItem aboutMenuItem = new JMenuItem();
-		JToolBar toolBar1 = new JToolBar();
+		toolBar = new JToolBar();
 		JButton backButton = new JButton();
 		JButton forwardButton = new JButton();
 		JButton cutButton = new JButton();
@@ -671,43 +748,43 @@ class DemoFrame
 		}
 		setJMenuBar(menuBar1);
 
-		//======== toolBar1 ========
+		//======== toolBar ========
 		{
-			toolBar1.setMargin(new Insets(3, 3, 3, 3));
+			toolBar.setMargin(new Insets(3, 3, 3, 3));
 
 			//---- backButton ----
 			backButton.setToolTipText("Back");
-			toolBar1.add(backButton);
+			toolBar.add(backButton);
 
 			//---- forwardButton ----
 			forwardButton.setToolTipText("Forward");
-			toolBar1.add(forwardButton);
-			toolBar1.addSeparator();
+			toolBar.add(forwardButton);
+			toolBar.addSeparator();
 
 			//---- cutButton ----
 			cutButton.setToolTipText("Cut");
-			toolBar1.add(cutButton);
+			toolBar.add(cutButton);
 
 			//---- copyButton ----
 			copyButton.setToolTipText("Copy");
-			toolBar1.add(copyButton);
+			toolBar.add(copyButton);
 
 			//---- pasteButton ----
 			pasteButton.setToolTipText("Paste");
-			toolBar1.add(pasteButton);
-			toolBar1.addSeparator();
+			toolBar.add(pasteButton);
+			toolBar.addSeparator();
 
 			//---- refreshButton ----
 			refreshButton.setToolTipText("Refresh");
-			toolBar1.add(refreshButton);
-			toolBar1.addSeparator();
+			toolBar.add(refreshButton);
+			toolBar.addSeparator();
 
 			//---- showToggleButton ----
 			showToggleButton.setSelected(true);
 			showToggleButton.setToolTipText("Show Details");
-			toolBar1.add(showToggleButton);
+			toolBar.add(showToggleButton);
 		}
-		contentPane.add(toolBar1, BorderLayout.NORTH);
+		contentPane.add(toolBar, BorderLayout.NORTH);
 
 		//======== contentPanel ========
 		{
@@ -813,8 +890,37 @@ class DemoFrame
 	private JCheckBoxMenuItem underlineMenuSelectionMenuItem;
 	private JCheckBoxMenuItem alwaysShowMnemonicsMenuItem;
 	private JCheckBoxMenuItem animatedLafChangeMenuItem;
+	private JToolBar toolBar;
 	private JTabbedPane tabbedPane;
 	private ControlBar controlBar;
 	IJThemesPanel themesPanel;
 	// JFormDesigner - End of variables declaration  //GEN-END:variables
+
+	//---- class AccentColorIcon ----------------------------------------------
+
+	private static class AccentColorIcon
+		extends FlatAbstractIcon
+	{
+		private final String colorKey;
+
+		AccentColorIcon( String colorKey ) {
+			super( 16, 16, null );
+			this.colorKey = colorKey;
+		}
+
+		@Override
+		protected void paintIcon( Component c, Graphics2D g ) {
+			Color color = UIManager.getColor( colorKey );
+			if( color == null )
+				color = Color.lightGray;
+			else if( !c.isEnabled() ) {
+				color = FlatLaf.isLafDark()
+					? ColorFunctions.shade( color, 0.5f )
+					: ColorFunctions.tint( color, 0.6f );
+			}
+
+			g.setColor( color );
+			g.fillRoundRect( 1, 1, width - 2, height - 2, 5, 5 );
+		}
+	}
 }

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

@@ -1,4 +1,4 @@
-JFDML JFormDesigner: "7.0.3.1.342" Java: "16" encoding: "UTF-8"
+JFDML JFormDesigner: "7.0.4.0.360" Java: "11.0.11" encoding: "UTF-8"
 
 new FormModel {
 	contentType: "form/swing"
@@ -13,8 +13,11 @@ new FormModel {
 			"$locationPolicy": 2
 			"$sizePolicy": 2
 			add( new FormContainer( "javax.swing.JToolBar", new FormLayoutManager( class javax.swing.JToolBar ) ) {
-				name: "toolBar1"
+				name: "toolBar"
 				"margin": new java.awt.Insets( 3, 3, 3, 3 )
+				auxiliary() {
+					"JavaCodeGenerator.variableLocal": false
+				}
 				add( new FormComponent( "javax.swing.JButton" ) {
 					name: "backButton"
 					"toolTipText": "Back"

flatlaf-demo/src/main/resources/com/formdev/flatlaf/demo/FlatDarkLaf.properties

@@ -14,4 +14,16 @@
 # limitations under the License.
 #
 
+#---- Demo.accent ----
+
+Demo.accent.blue = #4B6EAF
+Demo.accent.purple = #BF5AF2
+Demo.accent.red  = #e81123
+Demo.accent.orange = #FF9F0A
+Demo.accent.yellow = #FFCC00
+Demo.accent.green = #32D74B
+
+
+#---- HintPanel ----
+
 HintPanel.backgroundColor = darken(#ffffe1,80%)

flatlaf-demo/src/main/resources/com/formdev/flatlaf/demo/FlatLightLaf.properties

@@ -14,4 +14,16 @@
 # limitations under the License.
 #
 
+#---- Demo.accent ----
+
+Demo.accent.blue = #2675BF
+Demo.accent.purple = #BF5AF2
+Demo.accent.red = #FF3B30
+Demo.accent.orange = #FF9500
+Demo.accent.yellow = #FFCC00
+Demo.accent.green = #28CD41
+
+
+#---- HintPanel ----
+
 HintPanel.backgroundColor = #ffffe1