Native window decorations: updated maximize and restore icons for Windows 11 style

(requires Java 8u321, 11.0.14, 17.0.2 or 18+)

CHANGELOG.md

@@ -28,7 +28,8 @@ FlatLaf Change Log
   in FlatLaf 1.x). (issue #454)
 - Native window decorations: Fixed blurry iconify/maximize/close button hover
   rectangles at 125%, 150% or 175% scaling. (issue #431)
-
+- Native window decorations: Updated maximize and restore icons for Windows 11
+  style. (requires Java 8u321, 11.0.14, 17.0.2 or 18+)
 
 ## 2.0-rc1
 

flatlaf-core/src/main/java/com/formdev/flatlaf/icons/FlatWindowCloseIcon.java

@@ -24,6 +24,7 @@ import java.awt.geom.Line2D;
 import java.awt.geom.Path2D;
 import javax.swing.UIManager;
 import com.formdev.flatlaf.ui.FlatButtonUI;
+import com.formdev.flatlaf.util.SystemInfo;
 
 /**
  * "close" icon for windows (frames and dialogs).
@@ -54,7 +55,7 @@ public class FlatWindowCloseIcon
 		int iy = y + ((height - iwh) / 2);
 		int ix2 = ix + iwh - 1;
 		int iy2 = iy + iwh - 1;
-		int thickness = (int) scaleFactor;
+		float thickness = SystemInfo.isWindows_11_orLater ? (float) scaleFactor : (int) scaleFactor;
 
 		Path2D path = new Path2D.Float( Path2D.WIND_EVEN_ODD );
 		path.append( new Line2D.Float( ix, iy, ix2, iy2 ), false );

flatlaf-core/src/main/java/com/formdev/flatlaf/icons/FlatWindowMaximizeIcon.java

@@ -18,6 +18,7 @@ package com.formdev.flatlaf.icons;
 
 import java.awt.Graphics2D;
 import com.formdev.flatlaf.ui.FlatUIUtils;
+import com.formdev.flatlaf.util.SystemInfo;
 
 /**
  * "maximize" icon for windows (frames and dialogs).
@@ -35,8 +36,11 @@ public class FlatWindowMaximizeIcon
 		int iwh = (int) (10 * scaleFactor);
 		int ix = x + ((width - iwh) / 2);
 		int iy = y + ((height - iwh) / 2);
-		int thickness = (int) scaleFactor;
+		float thickness = SystemInfo.isWindows_11_orLater ? (float) scaleFactor : (int) scaleFactor;
+		int arc = Math.max( (int) (1.5 * scaleFactor), 2 );
 
-		g.fill( FlatUIUtils.createRectangle( ix, iy, iwh, iwh, thickness ) );
+		g.fill( SystemInfo.isWindows_11_orLater
+			? FlatUIUtils.createRoundRectangle( ix, iy, iwh, iwh, thickness, arc, arc, arc, arc )
+			: FlatUIUtils.createRectangle( ix, iy, iwh, iwh, thickness ) );
 	}
 }

flatlaf-core/src/main/java/com/formdev/flatlaf/icons/FlatWindowRestoreIcon.java

@@ -21,6 +21,7 @@ import java.awt.geom.Area;
 import java.awt.geom.Path2D;
 import java.awt.geom.Rectangle2D;
 import com.formdev.flatlaf.ui.FlatUIUtils;
+import com.formdev.flatlaf.util.SystemInfo;
 
 /**
  * "restore" icon for windows (frames and dialogs).
@@ -38,18 +39,33 @@ public class FlatWindowRestoreIcon
 		int iwh = (int) (10 * scaleFactor);
 		int ix = x + ((width - iwh) / 2);
 		int iy = y + ((height - iwh) / 2);
-		int thickness = (int) scaleFactor;
+		float thickness = SystemInfo.isWindows_11_orLater ? (float) scaleFactor : (int) scaleFactor;
+		int arc = Math.max( (int) (1.5 * scaleFactor), 2 );
+		int arcOuter = (int) (arc + (1.5 * scaleFactor));
 
 		int rwh = (int) (8 * scaleFactor);
 		int ro2 = iwh - rwh;
 
-		Path2D r1 = FlatUIUtils.createRectangle( ix + ro2, iy, rwh, rwh, thickness );
-		Path2D r2 = FlatUIUtils.createRectangle( ix, iy + ro2, rwh, rwh, thickness );
+		// upper-right rectangle
+		Path2D r1 = SystemInfo.isWindows_11_orLater
+			? FlatUIUtils.createRoundRectangle( ix + ro2, iy, rwh, rwh, thickness, arc, arcOuter, arc, arc )
+			: FlatUIUtils.createRectangle( ix + ro2, iy, rwh, rwh, thickness );
 
+		// lower-left rectangle
+		Path2D r2 = SystemInfo.isWindows_11_orLater
+			? FlatUIUtils.createRoundRectangle( ix, iy + ro2, rwh, rwh, thickness, arc, arc, arc, arc )
+			: FlatUIUtils.createRectangle( ix, iy + ro2, rwh, rwh, thickness );
+
+		// paint upper-right rectangle
 		Area area = new Area( r1 );
+		if( SystemInfo.isWindows_11_orLater ) {
+			area.subtract( new Area( new Rectangle2D.Float( ix, (float) (iy + scaleFactor), rwh, rwh ) ) );
+			area.subtract( new Area( new Rectangle2D.Float( (float) (ix + scaleFactor), iy + ro2, rwh, rwh ) ) );
+		} else
 			area.subtract( new Area( new Rectangle2D.Float( ix, iy + ro2, rwh, rwh ) ) );
 		g.fill( area );
 
+		// paint lower-left rectangle
 		g.fill( r2 );
 	}
 }