Button: optionally support gradient border and gradient background for improved compatibility with IntelliJ platform themes (e.g. Vuesion and Spacegray themes)

CHANGELOG.md

@@ -4,6 +4,9 @@ FlatLaf Change Log
 ## Unreleased
 
 - `FlatLaf.isNativeLookAndFeel()` now returns `false`.
+- Button: Optionally support gradient border and gradient background for
+  improved compatibility with IntelliJ platform themes (e.g. Vuesion and
+  Spacegray themes).
 
 
 ## 0.20

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

@@ -380,17 +380,6 @@ public class IntelliJTheme
 	private static Set<String> noWildcardReplace = new HashSet<>();
 
 	static {
-		// Button
-		// IDEA buttons support gradient for background and border, but FlatLaf does not
-		uiKeyMapping.put( "Button.startBackground",          "Button.background" );
-		uiKeyMapping.put( "Button.startBorderColor",         "Button.borderColor" );
-		uiKeyMapping.put( "Button.default.startBackground",  "Button.default.background" );
-		uiKeyMapping.put( "Button.default.startBorderColor", "Button.default.borderColor" );
-		uiKeyMapping.put( "Button.endBackground",            "" ); // ignore
-		uiKeyMapping.put( "Button.endBorderColor",           "" ); // ignore
-		uiKeyMapping.put( "Button.default.endBackground",    "" ); // ignore
-		uiKeyMapping.put( "Button.default.endBorderColor",   "" ); // ignore
-
 		// ComboBox
 		uiKeyMapping.put( "ComboBox.background",                        "" ); // ignore
 		uiKeyMapping.put( "ComboBox.nonEditableBackground",             "ComboBox.background" );

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

@@ -23,6 +23,7 @@ import java.awt.Graphics;
 import java.awt.Graphics2D;
 import java.awt.Insets;
 import java.awt.KeyboardFocusManager;
+import java.awt.Paint;
 import javax.swing.JComboBox;
 import javax.swing.JComponent;
 import javax.swing.JScrollPane;
@@ -82,7 +83,7 @@ public class FlatBorder
 					getLineWidth() + scale( (float) innerFocusWidth ), arc );
 			}
 
-			g2.setColor( getBorderColor( c ) );
+			g2.setPaint( getBorderColor( c ) );
 			FlatUIUtils.drawRoundRectangle( g2, x, y, width, height, focusWidth, borderWidth, arc );
 		} finally {
 			g2.dispose();
@@ -93,7 +94,7 @@ public class FlatBorder
 		return focusColor;
 	}
 
-	protected Color getBorderColor( Component c ) {
+	protected Paint getBorderColor( Component c ) {
 		boolean enabled = c.isEnabled() && (!(c instanceof JTextComponent) || ((JTextComponent)c).isEditable());
 		return enabled
 			? (isFocused( c ) ? focusedBorderColor : borderColor)

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

@@ -19,8 +19,10 @@ package com.formdev.flatlaf.ui;
 import static com.formdev.flatlaf.util.UIScale.scale;
 import java.awt.Color;
 import java.awt.Component;
+import java.awt.GradientPaint;
 import java.awt.Graphics;
 import java.awt.Insets;
+import java.awt.Paint;
 import javax.swing.JButton;
 import javax.swing.UIManager;
 import javax.swing.plaf.UIResource;
@@ -29,10 +31,14 @@ import javax.swing.plaf.UIResource;
  * Border for {@link javax.swing.JButton}.
  *
  * @uiDefault Button.borderColor				Color
+ * @uiDefault Button.startBorderColor			Color	optional; if set, a gradient paint is used and Button.borderColor is ignored
+ * @uiDefault Button.endBorderColor				Color	optional; if set, a gradient paint is used
  * @uiDefault Button.disabledBorderColor		Color
  * @uiDefault Button.focusedBorderColor			Color
  * @uiDefault Button.hoverBorderColor			Color	optional
  * @uiDefault Button.default.borderColor		Color
+ * @uiDefault Button.default.startBorderColor	Color	optional; if set, a gradient paint is used and Button.default.borderColor is ignored
+ * @uiDefault Button.default.endBorderColor		Color	optional; if set, a gradient paint is used
  * @uiDefault Button.default.hoverBorderColor	Color	optional
  * @uiDefault Button.default.focusedBorderColor	Color
  * @uiDefault Button.default.focusColor			Color
@@ -44,11 +50,13 @@ import javax.swing.plaf.UIResource;
 public class FlatButtonBorder
 	extends FlatBorder
 {
-	protected final Color borderColor = UIManager.getColor( "Button.borderColor" );
+	protected final Color borderColor = FlatUIUtils.getUIColor( "Button.startBorderColor", "Button.borderColor" );
+	protected final Color endBorderColor = UIManager.getColor( "Button.endBorderColor" );
 	protected final Color disabledBorderColor = UIManager.getColor( "Button.disabledBorderColor" );
 	protected final Color focusedBorderColor = UIManager.getColor( "Button.focusedBorderColor" );
 	protected final Color hoverBorderColor = UIManager.getColor( "Button.hoverBorderColor" );
-	protected final Color defaultBorderColor = UIManager.getColor( "Button.default.borderColor" );
+	protected final Color defaultBorderColor = FlatUIUtils.getUIColor( "Button.default.startBorderColor", "Button.default.borderColor" );
+	protected final Color defaultEndBorderColor = UIManager.getColor( "Button.default.endBorderColor" );
 	protected final Color defaultHoverBorderColor = UIManager.getColor( "Button.default.hoverBorderColor" );
 	protected final Color defaultFocusedBorderColor = UIManager.getColor( "Button.default.focusedBorderColor" );
 	protected final Color defaultFocusColor = UIManager.getColor( "Button.default.focusColor" );
@@ -67,14 +75,22 @@ public class FlatButtonBorder
 	}
 
 	@Override
-	protected Color getBorderColor( Component c ) {
+	protected Paint getBorderColor( Component c ) {
 		boolean def = FlatButtonUI.isDefaultButton( c );
-		return FlatButtonUI.buttonStateColor( c,
+		Paint color = FlatButtonUI.buttonStateColor( c,
 			def ? defaultBorderColor : borderColor,
 			disabledBorderColor,
 			def ? defaultFocusedBorderColor : focusedBorderColor,
 			def ? defaultHoverBorderColor : hoverBorderColor,
 			null );
+
+		// change to gradient paint if start/end colors are specified
+		Color startBg = def ? defaultBorderColor : borderColor;
+		Color endBg = def ? defaultEndBorderColor : endBorderColor;
+		if( color == startBg && endBg != null && !startBg.equals( endBg ) )
+			color = new GradientPaint( 0, 0, startBg, 0, c.getHeight(), endBg );
+
+		return color;
 	}
 
 	@Override

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

@@ -23,6 +23,7 @@ import java.awt.Component;
 import java.awt.Dimension;
 import java.awt.Font;
 import java.awt.FontMetrics;
+import java.awt.GradientPaint;
 import java.awt.Graphics;
 import java.awt.Graphics2D;
 import java.awt.Rectangle;
@@ -58,11 +59,15 @@ import com.formdev.flatlaf.FlatLaf;
  * @uiDefault Button.arc						int
  * @uiDefault Button.minimumWidth				int
  * @uiDefault Button.iconTextGap				int
+ * @uiDefault Button.startBackground			Color	optional; if set, a gradient paint is used and Button.background is ignored
+ * @uiDefault Button.endBackground				Color	optional; if set, a gradient paint is used
  * @uiDefault Button.focusedBackground			Color	optional
  * @uiDefault Button.hoverBackground			Color	optional
  * @uiDefault Button.pressedBackground			Color	optional
  * @uiDefault Button.disabledText				Color
  * @uiDefault Button.default.background			Color
+ * @uiDefault Button.default.startBackground	Color	optional; if set, a gradient paint is used and Button.default.background is ignored
+ * @uiDefault Button.default.endBackground		Color	optional; if set, a gradient paint is used
  * @uiDefault Button.default.foreground			Color
  * @uiDefault Button.default.focusedBackground	Color	optional
  * @uiDefault Button.default.hoverBackground	Color	optional
@@ -81,12 +86,15 @@ public class FlatButtonUI
 	protected int minimumWidth;
 	protected int iconTextGap;
 
+	protected Color startBackground;
+	protected Color endBackground;
 	protected Color focusedBackground;
 	protected Color hoverBackground;
 	protected Color pressedBackground;
 	protected Color disabledText;
 
 	protected Color defaultBackground;
+	protected Color defaultEndBackground;
 	protected Color defaultForeground;
 	protected Color defaultFocusedBackground;
 	protected Color defaultHoverBackground;
@@ -120,12 +128,15 @@ public class FlatButtonUI
 			minimumWidth = UIManager.getInt( prefix + "minimumWidth" );
 			iconTextGap = FlatUIUtils.getUIInt( prefix + "iconTextGap", 4 );
 
+			startBackground = UIManager.getColor( prefix + "startBackground" );
+			endBackground = UIManager.getColor( prefix + "endBackground" );
 			focusedBackground = UIManager.getColor( prefix + "focusedBackground" );
 			hoverBackground = UIManager.getColor( prefix + "hoverBackground" );
 			pressedBackground = UIManager.getColor( prefix + "pressedBackground" );
 			disabledText = UIManager.getColor( prefix + "disabledText" );
 
-			defaultBackground = UIManager.getColor( "Button.default.background" );
+			defaultBackground = FlatUIUtils.getUIColor( "Button.default.startBackground", "Button.default.background" );
+			defaultEndBackground = UIManager.getColor( "Button.default.endBackground" );
 			defaultForeground = UIManager.getColor( "Button.default.foreground" );
 			defaultFocusedBackground = UIManager.getColor( "Button.default.focusedBackground" );
 			defaultHoverBackground = UIManager.getColor( "Button.default.hoverBackground" );
@@ -140,6 +151,12 @@ public class FlatButtonUI
 			defaults_initialized = true;
 		}
 
+		if( startBackground != null ) {
+			Color bg = b.getBackground();
+			if( bg == null || bg instanceof UIResource )
+				b.setBackground( startBackground );
+		}
+
 		LookAndFeel.installProperty( b, "opaque", false );
 		LookAndFeel.installProperty( b, "iconTextGap", scale( iconTextGap ) );
 
@@ -201,8 +218,14 @@ public class FlatButtonUI
 					Border border = c.getBorder();
 					float focusWidth = (border instanceof FlatBorder) ? scale( (float) this.focusWidth ) : 0;
 					float arc = (border instanceof FlatButtonBorder || isToolBarButton( c )) ? scale( (float) this.arc ) : 0;
+					boolean def = isDefaultButton( c );
+					Color startBg = def ? defaultBackground : startBackground;
+					Color endBg = def ? defaultEndBackground : endBackground;
 
-					FlatUIUtils.setColor( g2, background, isDefaultButton(c) ? defaultBackground : c.getBackground() );
+					if( background == startBg && endBg != null && !startBg.equals( endBg ) )
+						g2.setPaint( new GradientPaint( 0, 0, startBg, 0, c.getHeight(), endBg ) );
+					else
+						FlatUIUtils.setColor( g2, background, def ? defaultBackground : c.getBackground() );
 					FlatUIUtils.fillRoundRectangle( g2, 0, 0, c.getWidth(), c.getHeight(), focusWidth, arc );
 				} finally {
 					g2.dispose();

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

@@ -41,6 +41,8 @@ import javax.swing.plaf.ComponentUI;
  * @uiDefault ToggleButton.arc							int
  * @uiDefault ToggleButton.minimumWidth					int
  * @uiDefault ToggleButton.iconTextGap					int
+ * @uiDefault ToggleButton.startBackground				Color	optional; if set, a gradient paint is used and ToggleButton.background is ignored
+ * @uiDefault ToggleButton.endBackground				Color	optional; if set, a gradient paint is used
  * @uiDefault ToggleButton.pressedBackground			Color
  * @uiDefault ToggleButton.disabledText					Color
  * @uiDefault ToggleButton.toolbar.hoverBackground		Color

flatlaf-testing/src/main/resources/com/formdev/flatlaf/testing/FlatTestLaf.properties

@@ -47,22 +47,26 @@
 
 #---- Button ----
 
-Button.background=#ffffff
+Button.startBackground=#fff
+Button.endBackground=#bbb
 Button.focusedBackground=#00ffff
 Button.hoverBackground=#ffff00
 Button.pressedBackground=#FFC800
 
-Button.borderColor=#0000ff
+Button.startBorderColor=#00f
+Button.endBorderColor=#f00
 Button.disabledBorderColor=#000088
 Button.focusedBorderColor=#466d94
 Button.hoverBorderColor=#ff0000
 
-Button.default.background=#dddddd
+Button.default.startBackground=#ddd
+Button.default.endBackground=#888
 Button.default.foreground=#880000
 Button.default.focusedBackground=#00ffff
 Button.default.hoverBackground=#ffff00
 Button.default.pressedBackground=#FFC800
-Button.default.borderColor=#ff0000
+Button.default.startBorderColor=#f00
+Button.default.endBorderColor=#00f
 Button.default.hoverBorderColor=#ff0000
 Button.default.focusedBorderColor=#537699
 Button.default.focusColor=#ff0000

flatlaf-testing/src/main/resources/com/formdev/flatlaf/testing/swingx/FlatTestLaf.properties

@@ -69,3 +69,8 @@ TaskPane.titleOver=#0000aa
 TaskPane.specialTitleBackground=#00ffff
 TaskPane.specialTitleForeground=#444444
 TaskPane.specialTitleOver=#dd0000
+
+
+#---- TitledPanel ----
+
+JXTitledPanel.borderColor=@@Button.startBorderColor