support running on WinPE (issue #279)

CHANGELOG.md

@@ -8,6 +8,7 @@ FlatLaf Change Log
 - Native window decorations: Support disabling native window decorations per
   window. (set client property `JRootPane.useWindowDecorations` to `false` on
   root pane).
+- Support running on WinPE. (issue #279)
 
 #### Fixed bugs
 

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

@@ -157,7 +157,7 @@ public abstract class FlatLaf
 	 */
 	@Override
 	public boolean getSupportsWindowDecorations() {
-		if( SystemInfo.isProjector )
+		if( SystemInfo.isProjector || SystemInfo.isWinPE )
 			return false;
 
 		if( SystemInfo.isWindows_10_orLater &&
@@ -443,7 +443,10 @@ public abstract class FlatLaf
 		FontUIResource uiFont = null;
 
 		if( SystemInfo.isWindows ) {
-			Font winFont = (Font) Toolkit.getDefaultToolkit().getDesktopProperty( "win.messagebox.font" );
+			// on WinPE use "win.defaultGUI.font", which is usually Tahoma,
+			// because Segoe UI font is not available on WinPE
+			Font winFont = (Font) Toolkit.getDefaultToolkit().getDesktopProperty(
+				SystemInfo.isWinPE ? "win.defaultGUI.font" : "win.messagebox.font" );
 			if( winFont != null )
 				uiFont = createCompositeFont( winFont.getFamily(), winFont.getStyle(), winFont.getSize() );
 

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

@@ -242,8 +242,8 @@ public class FlatNativeWindowBorder
 		if( !SystemInfo.isWindows_10_orLater )
 			return;
 
-		// do not use when running in JetBrains Projector
-		if( SystemInfo.isProjector )
+		// do not use when running in JetBrains Projector or WinPE
+		if( SystemInfo.isProjector || SystemInfo.isWinPE )
 			return;
 
 		// check whether disabled via system property

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

@@ -56,6 +56,7 @@ public class SystemInfo
 
 	// other
 	/** @since 1.1 */ public static final boolean isProjector;
+	/** @since 1.1.1 */ public static final boolean isWinPE;
 
 	static {
 		// platforms
@@ -91,6 +92,7 @@ public class SystemInfo
 
 		// other
 		isProjector = Boolean.getBoolean( "org.jetbrains.projector.server.enable" );
+		isWinPE = isWindows && "X:\\Windows\\System32".equalsIgnoreCase( System.getProperty( "user.dir" ) );
 	}
 
 	public static long scanVersion( String version ) {