Button: paint focused border

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

@@ -45,6 +45,12 @@ public class FlatButtonBorder
 			float lineWidth = getLineWidth();
 			float arc = UIScale.scale( 6f ); //TODO
 
+			if( c.hasFocus() ) {
+				g2.setColor( UIManager.getColor( FlatButtonUI.isDefaultButton( c )
+					? "Button.default.focusColor" : "Component.focusColor" ) );
+				FlatUIUtils.paintOutlineBorder( g2, x, y, width, height, focusWidth, lineWidth, arc );
+			}
+
 			g2.setPaint( getBorderColor( c ) );
 			FlatUIUtils.drawRoundRectangle( g2, x, y, width, height, focusWidth, lineWidth, arc );
 		} finally {
@@ -55,6 +61,9 @@ public class FlatButtonBorder
 	private Paint getBorderColor( Component c ) {
 		if( c.isEnabled() ) {
 			boolean def = FlatButtonUI.isDefaultButton( c );
+			if( c.hasFocus() )
+				return UIManager.getColor( def ? "Button.default.focusedBorderColor" : "Button.focusedBorderColor" );
+
 			Color startColor = UIManager.getColor( def ? "Button.default.startBorderColor" : "Button.startBorderColor" );
 			Color endColor = UIManager.getColor( def ? "Button.default.endBorderColor" : "Button.endBorderColor" );
 			return (startColor.equals( endColor ) )

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

@@ -23,6 +23,7 @@ import java.awt.RenderingHints;
 import java.awt.geom.Path2D;
 import java.awt.geom.RoundRectangle2D;
 import javax.swing.JComponent;
+import com.formdev.flatlaf.util.UIScale;
 
 /**
  * Utility methods for UI delegates.
@@ -96,4 +97,41 @@ public class FlatUIUtils
 		}
 		return null;
 	}
+
+	/**
+	 * Paints an outline border.
+	 */
+	public static void paintOutlineBorder( Graphics2D g, int x, int y, int width, int height,
+		float focusWidth, float lineWidth, float arc )
+	{
+		float x1 = x;
+		float y1 = y;
+		float x2 = x1 + width;
+		float y2 = y1 + height;
+
+		float outerArc = arc > 0 ? arc + focusWidth - UIScale.scale( 2f ) : focusWidth;
+		Path2D outerRect = createOutlinePath( x1, y1, x2, y2, outerArc );
+
+		float ow = focusWidth + lineWidth;
+		Path2D innerRect = createOutlinePath( x1 + ow, y1 + ow, x2 - ow, y2 - ow, outerArc - ow );
+
+		Path2D path = new Path2D.Float( Path2D.WIND_EVEN_ODD );
+		path.append( outerRect, false );
+		path.append( innerRect, false );
+		g.fill( path );
+	}
+
+	private static Path2D createOutlinePath( float x1, float y1, float x2, float y2, float arc ) {
+		Path2D rect = new Path2D.Float( Path2D.WIND_EVEN_ODD );
+		rect.moveTo( x2 - arc, y1 );
+		rect.quadTo( x2, y1, x2, y1 + arc );
+		rect.lineTo( x2, y2 - arc );
+		rect.quadTo( x2, y2, x2 - arc, y2 );
+		rect.lineTo( x1 + arc, y2 );
+		rect.quadTo( x1, y2, x1, y2 - arc );
+		rect.lineTo( x1, y1 + arc );
+		rect.quadTo( x1, y1, x1 + arc, y1 );
+		rect.closePath();
+		return rect;
+	}
 }

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

@@ -50,11 +50,19 @@ Button.disabledText=777777
 Button.startBorderColor=5e6060
 Button.endBorderColor=5e6060
 Button.disabledBorderColor=5e6060
+Button.focusedBorderColor=466d94
 
 Button.default.background=365880
 Button.default.foreground=bbbbbb
 Button.default.startBorderColor=4c708c
 Button.default.endBorderColor=4c708c
+Button.default.focusedBorderColor=537699
+Button.default.focusColor=43688c
+
+
+#---- Component ----
+
+Component.focusColor=3d6185
 
 
 #---- Label ----

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

@@ -50,11 +50,19 @@ Button.disabledText=999999
 Button.startBorderColor=bfbfbf
 Button.endBorderColor=b3b3b3
 Button.disabledBorderColor=cfcfcf
+Button.focusedBorderColor=87afda
 
 Button.default.background=4A86C7
 Button.default.foreground=f0f0f0
 Button.default.startBorderColor=4779ba
 Button.default.endBorderColor=3167ad
+Button.default.focusedBorderColor=a8cef6
+Button.default.focusColor=97c3f3
+
+
+#---- Component ----
+
+Component.focusColor=97c3f3
 
 
 #---- Label ----

flatlaf-core/src/test/resources/com/formdev/flatlaf/FlatTestLaf.properties

@@ -28,11 +28,19 @@ Button.disabledText=000088
 Button.startBorderColor=ff0000
 Button.endBorderColor=0000ff
 Button.disabledBorderColor=000088
+Button.focusedBorderColor=466d94
 
 Button.default.background=dddddd
 Button.default.foreground=880000
 Button.default.startBorderColor=ff0000
 Button.default.endBorderColor=ff0000
+Button.default.focusedBorderColor=537699
+Button.default.focusColor=ff0000
+
+
+#---- Component ----
+
+Component.focusColor=97c3f3
 
 
 #---- Label ----