8173321: TableView: Click on right trough has no effect when cell hei…

…ght is higher than viewport height

Reviewed-by: kcr, aghaisas

modules/javafx.controls/src/main/java/com/sun/javafx/scene/control/VirtualScrollBar.java

@@ -129,18 +129,35 @@ public final BooleanProperty virtualProperty() {
         if (isVirtual()) {
             adjusting = true;
             double oldValue = flow.getPosition();
-
-            double newValue = ((getMax() - getMin()) * Utils.clamp(0, pos, 1))+getMin();
-            if (newValue < oldValue) {
-                IndexedCell cell = flow.getFirstVisibleCell();
-                if (cell == null) return;
-                flow.scrollToBottom(cell);
-            } else if (newValue > oldValue) {
-                IndexedCell cell = flow.getLastVisibleCell();
-                if (cell == null) return;
-                flow.scrollToTop(cell);
+            double newValue = ((getMax() - getMin()) * Utils.clamp(0, pos, 1)) + getMin();
+            /**
+             * Scroll one cell further in the direction the user has clicked if only one cell is shown.
+             * Otherwise, a click on the trough would have no effect when cell height > viewport height.
+             */
+            IndexedCell firstVisibleCell = flow.getFirstVisibleCell();
+            IndexedCell lastVisibleCell = flow.getLastVisibleCell();
+            if (firstVisibleCell != null && firstVisibleCell == lastVisibleCell) {
+                int index = firstVisibleCell.getIndex();
+                if (newValue < oldValue) {
+                    flow.scrollTo(index - 1);
+                } else {
+                    flow.scrollTo(index + 1);
+                }
+            } else {
+                if (newValue < oldValue) {
+                    IndexedCell cell = firstVisibleCell;
+                    if (cell == null) {
+                        return;
+                    }
+                    flow.scrollToBottom(cell);
+                } else if (newValue > oldValue) {
+                    IndexedCell cell = lastVisibleCell;
+                    if (cell == null) {
+                        return;
+                    }
+                    flow.scrollToTop(cell);
+                }
             }
-
             adjusting = false;
         } else {
             super.adjustValue(pos);

tests/system/src/test/java/test/robot/javafx/scene/tableview/TableViewClickOnTroughTest.java

@@ -0,0 +1,185 @@
+/*
+ * Copyright (c) 2018, 2023, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package test.robot.javafx.scene.tableview;
+
+import static org.junit.Assert.assertNotNull;
+
+import java.util.concurrent.CountDownLatch;
+
+import org.junit.AfterClass;
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import javafx.application.Application;
+import javafx.application.Platform;
+import javafx.beans.property.SimpleStringProperty;
+import javafx.beans.property.StringProperty;
+import javafx.geometry.Bounds;
+import javafx.scene.Scene;
+import javafx.scene.control.ScrollBar;
+import javafx.scene.control.TableCell;
+import javafx.scene.control.TableColumn;
+import javafx.scene.control.TableRow;
+import javafx.scene.control.TableView;
+import javafx.scene.control.cell.PropertyValueFactory;
+import javafx.scene.input.MouseButton;
+import javafx.scene.layout.StackPane;
+import javafx.scene.robot.Robot;
+import javafx.scene.text.Font;
+import javafx.stage.Stage;
+import javafx.stage.StageStyle;
+import javafx.stage.WindowEvent;
+import javafx.util.Callback;
+import test.util.Util;
+
+/*
+ * [openjdk/jfx] 8173321: Click on trough has no effect when cell height > viewport (PR #985):
+ * Test to verify
+ * - click on trough moves the Scrollbar even if the table cell's height is greater than the table's height
+ * - size of ScrollBar is greater than minimum size even if the table cell's height is greater than the table's height
+ */
+public class TableViewClickOnTroughTest {
+
+    static Robot robot;
+    static volatile Stage stage;
+    static volatile Scene scene;
+    static final int SCENE_WIDTH = 800;
+    static final int SCENE_HEIGHT = 250;
+    static final CountDownLatch startupLatch = new CountDownLatch(1);
+
+    private static TableView<TableEntry> table;
+
+    public static void main(String[] args) {
+        TableViewClickOnTroughTest test = new TableViewClickOnTroughTest();
+        test.moveTroughTest();
+    }
+
+    @Test
+    public void moveTroughTest() {
+        ScrollBar verticalBar = (ScrollBar) table.lookup(".scroll-bar:vertical");
+        assertNotNull(verticalBar);
+        StackPane thumb = (StackPane) verticalBar.getChildrenUnmodifiable().stream()
+                .filter(c -> c.getStyleClass().contains("thumb")).findFirst().orElse(null);
+        assertNotNull(thumb);
+        Bounds verticalBarBoundsInScreen = verticalBar.localToScreen(verticalBar.getBoundsInLocal());
+        Bounds thumbBoundsInScreen = thumb.localToScreen(thumb.getBoundsInLocal());
+        double posX = verticalBarBoundsInScreen.getCenterX();
+        // set posY to point into the middle of the area of the verticalBar under the
+        // thumb.
+        double posY = verticalBarBoundsInScreen.getMaxY()
+                - ((verticalBarBoundsInScreen.getMaxY() - thumbBoundsInScreen.getMaxY()) / 2.0);
+        double oldPosition = verticalBar.getValue();
+
+        Util.runAndWait(() -> {
+            robot.mouseMove((int) posX, (int) posY);
+            robot.mousePress(MouseButton.PRIMARY);
+            robot.mouseRelease(MouseButton.PRIMARY);
+        });
+        Util.sleep(1000); // Delay for table moving Scrollbar
+        double newPosition = verticalBar.getValue();
+        Assert.assertNotEquals(oldPosition, newPosition, 0.1);
+    }
+
+    @BeforeClass
+    public static void initFX() {
+        Util.launch(startupLatch, TestApp.class);
+    }
+
+    @AfterClass
+    public static void exit() {
+        Util.shutdown(stage);
+    }
+
+    public static class TestApp extends Application {
+
+        @Override
+        public void start(Stage primaryStage) {
+            robot = new Robot();
+            stage = primaryStage;
+
+            primaryStage.setTitle("TableView Test");
+            TableColumn<TableEntry, String> col = new TableColumn<>("First Name");
+
+            table = new TableView<TableEntry>();
+            table.getColumns().addAll(col);
+            table.getItems().addAll(new TableEntry("First"), new TableEntry("Second"), new TableEntry("Third"));
+            col.setCellValueFactory(new PropertyValueFactory<TableEntry, String>("name"));
+
+            col.setCellFactory(MyCellFactory.forTableColumn());
+
+            StackPane root = new StackPane();
+            root.getChildren().add(table);
+            scene = new Scene(root, SCENE_WIDTH, SCENE_HEIGHT);
+            stage.setScene(scene);
+            stage.initStyle(StageStyle.UNDECORATED);
+            stage.addEventHandler(WindowEvent.WINDOW_SHOWN, e -> Platform.runLater(startupLatch::countDown));
+            stage.setAlwaysOnTop(true);
+            stage.show();
+        }
+    }
+
+    public static class TableEntry {
+        StringProperty name = new SimpleStringProperty();
+
+        public TableEntry(String name) {
+            this.name.set(name);
+        }
+
+        public String getName() {
+            return name.get();
+        }
+
+        public void setName(String name) {
+            this.name.set(name);
+        }
+
+        @Override
+        public String toString() {
+            return "TableEntry [name=" + name + "]";
+        }
+    }
+
+    public static class MyCellFactory extends TableCell<TableEntry, String> {
+        public MyCellFactory() {
+            setFont(new Font("Times New Roman", 192));
+        }
+
+        @Override
+        protected void updateItem(String item, boolean empty) {
+            super.updateItem(item, empty);
+            if (empty || item == null) {
+                setText(null);
+                return;
+            }
+            setText(item);
+        }
+
+        public static Callback<TableColumn<TableEntry, String>, TableCell<TableEntry, String>> forTableColumn() {
+            return e -> new MyCellFactory();
+        }
+    }
+}