implement cancel operation for image tagging

src/main/kotlin/dev/nuculabs/imagetagger/ui/MainPage.kt

@@ -17,6 +17,7 @@ class MainPage : Application() {
 
         fxmlLoader = FXMLLoader(MainPage::class.java.getResource("main-window-view.fxml"))
         val scene = Scene(fxmlLoader.load(), 640.0, 760.0)
+        fxmlLoader.getController<MainPageController>().initialize()
         stage.title = "Image Tagger"
         stage.scene = scene
         stage.minWidth = 640.0

src/main/kotlin/dev/nuculabs/imagetagger/ui/MainPageController.kt

@@ -4,8 +4,11 @@ import dev.nuculabs.imagetagger.ai.ImageTagsPrediction
 import dev.nuculabs.imagetagger.ui.controls.ImageTagsEntryControl
 import javafx.application.Platform
 import javafx.fxml.FXML
+import javafx.scene.control.Button
 import javafx.scene.control.ProgressBar
 import javafx.scene.control.Separator
+import javafx.scene.layout.HBox
+import javafx.scene.layout.Priority
 import javafx.scene.layout.VBox
 import javafx.stage.FileChooser
 import java.io.File
@@ -50,6 +53,11 @@ class MainPageController {
      */
     private val imageTagsPrediction = ImageTagsPrediction.getInstance()
 
+    /**
+     * A boolean that when set to true it will stop the current image tagging operation.
+     * When a new operation is started the boolean is reset to false.
+     */
+    private var isCurrentTagsOperationCancelled: Boolean = false
 
     @FXML
     private lateinit var progressBar: ProgressBar
@@ -57,6 +65,16 @@ class MainPageController {
     @FXML
     private lateinit var verticalBox: VBox
 
+    @FXML
+    private lateinit var cancelButton: Button
+
+    /**
+     * Initializes the controller. Needs to be called after the dependencies have been injected.
+     */
+    fun initialize() {
+        HBox.setHgrow(progressBar, Priority.ALWAYS)
+        HBox.setHgrow(cancelButton, Priority.ALWAYS)
+    }
     /**
      * Prompts the user to select files then predicts tags for the selected image files.
      */
@@ -66,7 +84,9 @@ class MainPageController {
             val fileChooser = FileChooser().apply { title = "Choose images" }
             val filePaths = fileChooser.showOpenMultipleDialog(null) ?: return
 
+            isCurrentTagsOperationCancelled = false
             progressBar.isVisible = true
+            cancelButton.isVisible = true
             progressBar.progress = 0.0
             imageFilesTotal = filePaths.count()
             processedImageFilesCount.set(0)
@@ -74,8 +94,18 @@ class MainPageController {
             Thread {
                 logger.info("Analyzing $imageFilesTotal files")
                 filePaths.forEach { filePath ->
+                    if (isCurrentTagsOperationCancelled) {
+                        logger.info("Cancelling current prediction operation.")
+                        return@Thread
+                    }
                     workerSemaphore.acquire()
                     workerPool.submit {
+                        if (isCurrentTagsOperationCancelled) {
+                            logger.info("Image prediction task is cancelled.")
+                            workerSemaphore.release()
+                            return@submit
+                        }
+
                         predictImageTags(
                             filePath,
                             onError = {
@@ -96,6 +126,16 @@ class MainPageController {
         }
     }
 
+    /**
+     * Cancels the prediction operation.
+     */
+    @FXML
+    fun onCancelTagImagesClick() {
+        isCurrentTagsOperationCancelled = true
+        progressBar.isVisible = false
+        cancelButton.isVisible = false
+    }
+
     /**
      * Predicts an image tags and executes an action with it.
      *
@@ -140,6 +180,7 @@ class MainPageController {
             ((processedImageFilesCount.incrementAndGet() * 100) / imageFilesTotal).toDouble() / 100.0
         if (processedImageFilesCount.get() == imageFilesTotal) {
             progressBar.isVisible = false
+            cancelButton.isVisible = false
             logger.info("Finished processing images.")
         }
     }
@@ -148,6 +189,7 @@ class MainPageController {
      * Shuts down the MainPageController.
      */
     fun shutdown() {
+        isCurrentTagsOperationCancelled = true
         workerPool.shutdownNow()
     }
 }

src/main/resources/dev/nuculabs/imagetagger/ui/main-window-view.fxml

@@ -5,35 +5,46 @@
 <?import javafx.scene.layout.*?>
 
 <?import org.kordamp.ikonli.javafx.FontIcon?>
-<BorderPane prefHeight="537.0" prefWidth="725.0" xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/17.0.2-ea" fx:controller="dev.nuculabs.imagetagger.ui.MainPageController">
-  <padding>
-    <Insets bottom="20.0" left="30.0" right="30.0" top="20.0" />
-  </padding>
-  <top>
-    <HBox alignment="CENTER_LEFT">
-      <padding>
-        <Insets bottom="5" left="5" right="5"/>
-      </padding>
-      <Button onAction="#onTagImagesButtonClick" text="Tag Images">
-        <graphic>
-          <FontIcon iconLiteral="far-images" iconSize="16"/>
-        </graphic>
-      </Button>
-      <Separator orientation="VERTICAL" style="-fx-padding: 10px" />
-    </HBox>
-  </top>
-  <center>
-    <ScrollPane>
-      <VBox fx:id="verticalBox">
-      </VBox>
-    </ScrollPane>
-  </center>
+<BorderPane prefHeight="537.0" prefWidth="725.0" xmlns:fx="http://javafx.com/fxml/1"
+            xmlns="http://javafx.com/javafx/17.0.2-ea" fx:controller="dev.nuculabs.imagetagger.ui.MainPageController">
+    <padding>
+        <Insets bottom="20.0" left="30.0" right="30.0" top="20.0"/>
+    </padding>
+    <top>
+        <HBox alignment="CENTER_LEFT">
+            <padding>
+                <Insets bottom="5" left="5" right="5"/>
+            </padding>
+            <Button onAction="#onTagImagesButtonClick" text="Tag Images">
+                <graphic>
+                    <FontIcon iconLiteral="far-images" iconSize="16"/>
+                </graphic>
+            </Button>
+            <Separator orientation="VERTICAL" style="-fx-padding: 10px"/>
+        </HBox>
+    </top>
+    <center>
+        <ScrollPane fitToWidth="true" fitToHeight="true">
+            <VBox fx:id="verticalBox">
+            </VBox>
+        </ScrollPane>
+    </center>
 
-  <bottom>
-    <ProgressBar fx:id="progressBar" maxWidth="Infinity" visible="false">
-      <padding>
-        <Insets top="5" />
-      </padding>
-    </ProgressBar>
-  </bottom>
+    <bottom>
+        <HBox alignment="CENTER_LEFT" prefWidth="Infinity">
+            <padding>
+                <Insets top="5"/>
+            </padding>
+            <ProgressBar fx:id="progressBar" maxWidth="Infinity" visible="false">
+                <padding>
+                    <Insets right="5"/>
+                </padding>
+            </ProgressBar>
+            <Button fx:id="cancelButton" onAction="#onCancelTagImagesClick" alignment="CENTER_RIGHT" visible="false">
+                <graphic>
+                    <FontIcon iconLiteral="far-times-circle" iconColor="red" iconSize="16"/>
+                </graphic>
+            </Button>
+        </HBox>
+    </bottom>
 </BorderPane>