Move away from "Monocle" in favor of "Headless"

src/qz/common/TrayManager.java

@@ -293,10 +293,10 @@ private void addMenuItems() {
         monocleItem.setToolTipText("Use monocle platform for HTML printing (restart required)");
         monocleItem.setMnemonic(KeyEvent.VK_U);
         monocleItem.setState(getPref(TRAY_MONOCLE));
-        if(!SystemUtilities.hasMonocle()) {
-            log.warn("Monocle engine was not detected");
+        if(Constants.JAVA_VERSION.getMajorVersion() <= 8) {
+            log.warn("Monocle engine is not available for this Java version");
             monocleItem.setEnabled(false);
-            monocleItem.setToolTipText("Monocle HTML engine was not detected");
+            monocleItem.setToolTipText("Monocle HTML engine is not available.");
         }
         monocleItem.addActionListener(monocleListener);
 

src/qz/printer/action/html/WebApp.java

@@ -181,25 +181,31 @@ public static synchronized void initialize() throws IOException {
                     // Fallback for JDK11+
                     headless = true;
                 }
-                if (useMonocle && SystemUtilities.hasMonocle()) {
-                    log.trace("Initializing monocle platform");
-                    System.setProperty("javafx.platform", "monocle");
-                    // Don't set glass.platform on Linux per https://github.com/qzind/tray/issues/702
-                    switch(SystemUtilities.getOs()) {
-                        case WINDOWS:
-                        case MAC:
-                            System.setProperty("glass.platform", "Monocle");
-                            break;
-                        default:
-                            // don't set "glass.platform"
-                    }
+                if (useMonocle) {
+                    if(SystemUtilities.hasMonocle()) {
+                        // Legacy "Monocle" mode
+                        System.setProperty("javafx.platform", "monocle");
+                        // Don't set glass.platform on Linux per https://github.com/qzind/tray/issues/702
+                        switch(SystemUtilities.getOs()) {
+                            case WINDOWS:
+                            case MAC:
+                                System.setProperty("glass.platform", "Monocle");
+                                break;
+                            default:
+                                // don't set "glass.platform"
+                        }
 
-                    //software rendering required headless environments
-                    if (headless) {
-                        System.setProperty("prism.order", "sw");
+                        //software rendering required headless environments
+                        if (headless) {
+                            System.setProperty("prism.order", "sw");
+                        }
+                    } else {
+                        // Assume newer "Headless" mode is available
+                        System.setProperty("glass.platform", "Headless");
                     }
+                    log.trace("Initializing {} glass.platform", SystemUtilities.hasMonocle() ? "monocle" : "headless");
                 } else {
-                    log.warn("Monocle platform will not be used");
+                    log.warn("{} glass.platform will not be used", SystemUtilities.hasMonocle() ? "Monocle" : "Headless");
                 }
             }
 

src/qz/utils/SystemUtilities.java

@@ -70,6 +70,7 @@ public class SystemUtilities {
 
     private static Boolean darkDesktop;
     private static Boolean darkTaskbar;
+    @Deprecated
     private static Boolean hasMonocle;
     private static String classProtocol;
     private static Version osVersion;
@@ -655,6 +656,7 @@ public static boolean isJDK() {
         return false;
     }
 
+    @Deprecated
     public static boolean hasMonocle() {
         if(hasMonocle == null) {
             try {

test/qz/printer/action/WebAppTest.java

@@ -222,7 +222,8 @@ private static WebAppModel buildModel(String index, double width, double height,
     }
 
     private static PrinterJob buildVectorJob(String name) throws Throwable {
-        Printer defaultPrinter = Printer.getDefaultPrinter();
+        // Get "PDF" printer
+        Printer defaultPrinter = Printer.getAllPrinters().stream().filter(printer -> printer.getName().contains("PDF")).findFirst().get();
         PrinterJob job = PrinterJob.createPrinterJob(defaultPrinter);
 
         // All this to remove margins