Improve image preview performance on Linux

src/main/java/net/rptools/tokentool/controller/TokenTool_Controller.java

@@ -33,6 +33,7 @@
 import java.util.NavigableSet;
 import java.util.Optional;
 import java.util.TreeSet;
+import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -157,7 +158,6 @@ protected boolean removeEldestEntry(Map.Entry<Path, TreeItem<Path>> eldest) {
   @FXML private StackPane imagesStackPane;
   @FXML private ImageView backgroundImageView; // The background image layer
   @FXML private ImageView portraitImageView; // The bottom "Portrait" layer
-  @FXML private ImageView maskImageView; // The mask layer used to crop the Portrait layer
   @FXML private ImageView overlayImageView; // The overlay layer to apply on top of everything
   @FXML private ImageView tokenImageView; // The final token image created
   @FXML private CheckBox useFileNumberingCheckbox;
@@ -192,6 +192,13 @@ protected boolean removeEldestEntry(Map.Entry<Path, TreeItem<Path>> eldest) {
   @FXML private RadioMenuItem overlayMenuItem;
   private FileSaveUtil fileSaveUtil = new FileSaveUtil();
 
+  /**
+   * The mask layer used to crop the Portrait layer.
+   *
+   * <p>This is not part of the main scene, but is used when compositing result images.
+   */
+  private ImageView maskImageView;
+
   // A custom set of Width/Height sizes to use for Overlays
   private NavigableSet<Integer> overlaySpinnerSteps =
       new TreeSet<>(
@@ -252,8 +259,6 @@ void initialize() {
         : "fx:id=\"backgroundImageView\" was not injected: check your FXML file 'TokenTool.fxml'.";
     assert portraitImageView != null
         : "fx:id=\"portraitImageView\" was not injected: check your FXML file 'TokenTool.fxml'.";
-    assert maskImageView != null
-        : "fx:id=\"maskImageView\" was not injected: check your FXML file 'TokenTool.fxml'.";
     assert overlayImageView != null
         : "fx:id=\"overlayImageView\" was not injected: check your FXML file 'TokenTool.fxml'.";
     assert tokenImageView != null
@@ -325,6 +330,20 @@ void initialize() {
     assert overlayMenuItem != null
         : "fx:id=\"overlayMenuItem\" was not injected: check your FXML file 'TokenTool.fxml'.";
 
+    var defaultImageUrl =
+        getClass().getResource("/net/rptools/tokentool/image/gear-chrome-mask.png");
+    maskImageView =
+        defaultImageUrl == null ? new ImageView() : new ImageView(defaultImageUrl.toExternalForm());
+    maskImageView.setVisible(true);
+    maskImageView.setId("maskImageView");
+    maskImageView.setFitWidth(256);
+    maskImageView.setFitHeight(256);
+    maskImageView.setLayoutX(1);
+    maskImageView.setLayoutY(1);
+    maskImageView.setMouseTransparent(true);
+    maskImageView.setPickOnBounds(true);
+    maskImageView.setPreserveRatio(true);
+
     // We're getting the defaults set by the FXML before updating them with the saved preferences...
     AppConstants.DEFAULT_MASK_IMAGE = maskImageView.getImage();
     AppConstants.DEFAULT_OVERLAY_IMAGE = overlayImageView.getImage();
@@ -1232,17 +1251,29 @@ public void updateOverlayTreeview(TreeItem<Path> overlayTreeItems) {
   }
 
   public void updateTokenPreviewImageView() {
-    tokenImageView.setImage(
-        ImageUtil.composePreview(
-            compositeTokenPane,
-            backgroundImageView,
-            backgroundColorPicker.getValue(),
-            portraitImageView,
-            maskImageView,
-            overlayImageView,
-            overlayUseAsBaseCheckbox.isSelected(),
-            clipPortraitCheckbox.isSelected()));
-    tokenImageView.setPreserveRatio(true);
+    compositeTokenPane.layout();
+
+    boolean clip =
+        clipPortraitCheckbox.isSelected()
+            && maskImageView.getFitWidth() > 0
+            && maskImageView.getFitHeight() > 0;
+    CompletableFuture<? extends Image> future =
+        clip
+            ? ImageUtil.Async.composeClippedPreview(
+                backgroundImageView,
+                backgroundColorPicker.getValue(),
+                portraitImageView,
+                maskImageView,
+                overlayImageView,
+                overlayUseAsBaseCheckbox.isSelected())
+            : ImageUtil.Async.composeUnclippedPreview(compositeTokenPane);
+    future
+        .thenCompose(i -> ImageUtil.Async.autoCrop(i))
+        .thenAccept(
+            cropped -> {
+              tokenImageView.setImage(cropped);
+              tokenImageView.setPreserveRatio(true);
+            });
   }
 
   private void saveToken() {