8296330: Tests: Add layout container snapping tests

Reviewed-by: arapte

modules/javafx.graphics/src/test/java/test/javafx/scene/layout/SnappingTest.java

@@ -0,0 +1,179 @@
+/*
+ * Copyright (c) 2022, 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.javafx.scene.layout;
+
+import javafx.beans.property.DoubleProperty;
+import javafx.beans.property.SimpleDoubleProperty;
+import javafx.scene.Node;
+import javafx.scene.Scene;
+import javafx.scene.layout.GridPane;
+import javafx.scene.layout.HBox;
+import javafx.scene.layout.Pane;
+import javafx.scene.layout.Region;
+import javafx.scene.layout.VBox;
+import javafx.stage.Stage;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import java.util.function.Function;
+import java.util.stream.Stream;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * Tests the snapping of all container inside {@link javafx.scene.layout}.
+ * Containers must always snap their width/height as well as their insets, otherwise the children may look blurry or
+ * have other side effects. This also ensures that the containers and their children have the correct position and size
+ * on all different render scales.
+ *
+ * @see Stage#setRenderScaleX(double)
+ * @see Stage#setRenderScaleY(double)
+ * @see Region#snapPositionX(double)
+ * @see Region#snapPositionY(double)
+ */
+class SnappingTest {
+
+    private static final double EPSILON = 0.00001;
+
+    private Stage stage;
+
+    @AfterEach
+    void tearDown() {
+        if (stage != null) {
+            stage.hide();
+            stage = null;
+        }
+    }
+
+    @ParameterizedTest
+    @MethodSource(value = { "getContainerCreators" })
+    void testContainerSnappingScale100(ContainerCreator<Region> containerCreator) {
+        testContainerSnappingImpl(containerCreator, 1);
+    }
+
+    @ParameterizedTest
+    @MethodSource(value = { "getContainerCreators" })
+    void testContainerSnappingScale125(ContainerCreator<Region> containerCreator) {
+        testContainerSnappingImpl(containerCreator, 1.25);
+    }
+
+    @ParameterizedTest
+    @MethodSource(value = { "getContainerCreators" })
+    void testContainerSnappingScale150(ContainerCreator<Region> containerCreator) {
+        testContainerSnappingImpl(containerCreator, 1.5);
+    }
+
+    @ParameterizedTest
+    @MethodSource(value = { "getContainerCreators" })
+    void testContainerSnappingScale175(ContainerCreator<Region> containerCreator) {
+        testContainerSnappingImpl(containerCreator, 1.75);
+    }
+
+    @ParameterizedTest
+    @MethodSource(value = { "getContainerCreators" })
+    void testContainerSnappingScale200(ContainerCreator<Region> containerCreator) {
+        testContainerSnappingImpl(containerCreator, 2);
+    }
+
+    private void testContainerSnappingImpl(ContainerCreator<Region> containerCreator, double scale) {
+        double widthHeight = 100;
+        double padding = 9.6;
+
+        Region child = new Region();
+        child.setMinWidth(widthHeight);
+        child.setMinHeight(widthHeight);
+        child.setPrefWidth(widthHeight);
+        child.setPrefHeight(widthHeight);
+        child.setMaxWidth(widthHeight);
+        child.setMaxHeight(widthHeight);
+
+        Region container = containerCreator.apply(child);
+        container.setStyle("-fx-padding: " + padding + "px;");
+
+        DoubleProperty renderScaleProperty = new SimpleDoubleProperty(scale);
+
+        stage = new Stage();
+        stage.renderScaleXProperty().bind(renderScaleProperty);
+        stage.renderScaleYProperty().bind(renderScaleProperty);
+
+        Scene scene = new Scene(container, widthHeight, widthHeight);
+        stage.setScene(scene);
+        stage.show();
+
+        double snappedPaddingX = container.snapPositionX(padding) * 2;
+        double snappedPaddingY = container.snapPositionY(padding) * 2;
+
+        // Special case: The min width/height of the Pane is only the padding
+        String className = container.getClass().getSimpleName();
+        if (container.getClass() == Pane.class) {
+            assertEquals(snappedPaddingX, container.minWidth(-1), EPSILON, className);
+            assertEquals(snappedPaddingY, container.minHeight(-1), EPSILON, className);
+        } else {
+            assertEquals(widthHeight + snappedPaddingX, container.minWidth(-1), EPSILON, className);
+            assertEquals(widthHeight + snappedPaddingY, container.minHeight(-1), EPSILON, className);
+        }
+
+        assertEquals(widthHeight + snappedPaddingX, container.prefWidth(-1), EPSILON, className);
+        assertEquals(widthHeight + snappedPaddingY, container.prefHeight(-1), EPSILON, className);
+    }
+
+    static Stream<ContainerCreator<?>> getContainerCreators() {
+        // TODO: Create issues and fix snapping for all commented out layout containers below.
+        // The issues should be linked to JDK-8296609
+        // Note that the working layout containers do not necessarily use the optimized snappedXXXInsets() methods,
+        // but instead snap the insets (again). This can be optimized as well.
+        return Stream.of(
+                new ContainerCreator<>(HBox::new),
+                new ContainerCreator<>(VBox::new),
+                new ContainerCreator<>(node -> {
+                    GridPane gridPane = new GridPane();
+                    gridPane.getChildren().add(node);
+                    return gridPane;
+                })
+//                new ContainerCreator<>(Pane::new),
+//                new ContainerCreator<>(StackPane::new),
+//                new ContainerCreator<>(BorderPane::new),
+//                new ContainerCreator<>(node -> {
+//                    TilePane tilePane = new TilePane(node);
+//                    tilePane.setPrefColumns(1);
+//                    return tilePane;
+//                }),
+//                new ContainerCreator<>(AnchorPane::new), // fixed by JDK-8295078
+//                new ContainerCreator<>(node -> {
+//                    FlowPane flowPane = new FlowPane(node);
+//                    flowPane.setPrefWrapLength(0);
+//                    return flowPane;
+//                })
+        );
+    }
+
+    private record ContainerCreator<S extends Region>(Function<Node, S> containerCreatorFunction) {
+        public S apply(Node child) {
+            return containerCreatorFunction().apply(child);
+        }
+    }
+
+}