Completing Chapter 15 exercises;

ch_15/Exercise15_20.java

@@ -0,0 +1,101 @@
+package ch_15;
+
+import javafx.application.Application;
+import javafx.geometry.Point2D;
+import javafx.scene.Scene;
+import javafx.scene.layout.Pane;
+import javafx.scene.shape.Circle;
+import javafx.scene.shape.Line;
+import javafx.scene.text.Text;
+import javafx.stage.Stage;
+
+/**
+ * **15.20 (Geometry: display angles) Write a program that enables the user to drag the vertices of
+ * a triangle and displays the angles dynamically as the triangle shape changes,
+ * as shown in Figure 15.30a. The formula to compute angles is given in Listing 4.1.
+ * <p>
+ * FIGURE 15.30 (a) Exercise 15.20 enables the user to drag vertices and display the angles
+ * dynamically.
+ */
+public class Exercise15_20 extends Application {
+    private double radius = 10;
+    private Circle[] circle = {new Circle(40, 40, 10),
+            new Circle(140, 40, 10), new Circle(60, 140, 10)};
+    private Line line1 = new Line();
+    private Line line2 = new Line();
+    private Line line3 = new Line();
+    private Text[] text = {new Text(), new Text(), new Text()};
+
+    @Override
+    public void start(Stage primaryStage) {
+        Pane pane = new Pane();
+        setLines();
+        pane.getChildren().addAll(circle[0], circle[1], circle[2],
+                line1, line2, line3, text[0], text[1], text[2]);
+
+        Scene scene = new Scene(pane, 400, 250);
+        primaryStage.setTitle(getClass().getName());
+        primaryStage.setScene(scene);
+        primaryStage.show();
+
+        circle[0].setOnMouseDragged(e -> {
+            if (circle[0].contains(e.getX(), e.getY())) {
+                // Recompute and display angles
+                circle[0].setCenterX(e.getX());
+                circle[0].setCenterY(e.getY());
+                setLines();
+            }
+        });
+
+        circle[1].setOnMouseDragged(e -> {
+            if (circle[1].contains(e.getX(), e.getY())) {
+                // Recompute and display angles
+                circle[1].setCenterX(e.getX());
+                circle[1].setCenterY(e.getY());
+                setLines();
+            }
+        });
+
+        circle[2].setOnMouseDragged(e -> {
+            if (circle[2].contains(e.getX(), e.getY())) {
+                // Recompute and display angles
+                circle[2].setCenterX(e.getX());
+                circle[2].setCenterY(e.getY());
+                setLines();
+            }
+        });
+    }
+
+    private void setLines() {
+        line1.setStartX(circle[0].getCenterX());
+        line1.setStartY(circle[0].getCenterY());
+        line1.setEndX(circle[1].getCenterX());
+        line1.setEndY(circle[1].getCenterY());
+        line2.setStartX(circle[0].getCenterX());
+        line2.setStartY(circle[0].getCenterY());
+        line2.setEndX(circle[2].getCenterX());
+        line2.setEndY(circle[2].getCenterY());
+        line3.setStartX(circle[1].getCenterX());
+        line3.setStartY(circle[1].getCenterY());
+        line3.setEndX(circle[2].getCenterX());
+        line3.setEndY(circle[2].getCenterY());
+
+        // Compute angles
+        double a = new Point2D(circle[2].getCenterX(), circle[2].getCenterY()).
+                distance(circle[1].getCenterX(), circle[1].getCenterY());
+        double b = new Point2D(circle[2].getCenterX(), circle[2].getCenterY()).
+                distance(circle[0].getCenterX(), circle[0].getCenterY());
+        double c = new Point2D(circle[1].getCenterX(), circle[1].getCenterY()).
+                distance(circle[0].getCenterX(), circle[0].getCenterY());
+        double[] angle = new double[3];
+        angle[0] = Math.acos((a * a - b * b - c * c) / (-2 * b * c));
+        angle[1] = Math.acos((b * b - a * a - c * c) / (-2 * a * c));
+        angle[2] = Math.acos((c * c - b * b - a * a) / (-2 * a * b));
+
+        for (int i = 0; i < 3; i++) {
+            text[i].setX(circle[i].getCenterX());
+            text[i].setY(circle[i].getCenterY() - radius);
+            text[i].setText(String.format("%.2f", Math.toDegrees(angle[i])));
+        }
+    }
+}

ch_15/Exercise15_22.java

@@ -0,0 +1,79 @@
+package ch_15;
+
+
+import javafx.application.Application;
+import javafx.scene.Scene;
+import javafx.scene.layout.Pane;
+import javafx.scene.paint.Color;
+import javafx.scene.shape.Arc;
+import javafx.scene.shape.Ellipse;
+import javafx.scene.shape.Line;
+import javafx.stage.Stage;
+
+/**
+ * 15.22 (Auto resize cylinder) Rewrite Programming Exercise 14.10 so
+ * that the cylinder’s width and height are automatically resized when the window is resized.
+ */
+public class Exercise15_22 extends Application {
+    private double paneWidth = 200;
+    private double paneHeight = 200;
+
+    Ellipse ellipse = new Ellipse(100, 40, 50, 20);
+    Arc arc1 = new Arc(100, 140, 50, 20, 0, 180);
+    Arc arc2 = new Arc(100, 140, 50, 20, 180, 180);
+    Line line1 = new Line(50, 40, 50, 140);
+    Line line2 = new Line(150, 40, 150, 140);
+
+    @Override
+    public void start(Stage primaryStage) {
+        Pane pane = new Pane();
+
+        ellipse.setFill(Color.WHITE);
+        ellipse.setStroke(Color.BLACK);
+
+        arc1.setFill(Color.WHITE);
+        arc1.setStroke(Color.BLACK);
+        arc1.getStrokeDashArray().addAll(6d, 21d);
+
+        arc2.setFill(Color.WHITE);
+        arc2.setStroke(Color.BLACK);
+
+        pane.getChildren().addAll(ellipse, arc1, arc2, line1, line2);
+
+        Scene scene = new Scene(pane, 200, 200);
+        primaryStage.setTitle(getClass().getName());
+        primaryStage.setScene(scene);
+        primaryStage.show();
+
+        scene.widthProperty().addListener(ov -> {
+            paneWidth = pane.getWidth();
+            setValues();
+        });
+
+        scene.heightProperty().addListener(ov -> {
+            paneHeight = pane.getHeight();
+            setValues();
+        });
+    }
+
+    private void setValues() {
+        ellipse.setCenterX(paneWidth / 2);
+        ellipse.setRadiusX(paneWidth / 4);
+
+        arc1.setCenterX(paneWidth / 2);
+        arc1.setCenterY(paneHeight - 40);
+        arc1.setRadiusX(paneWidth / 4);
+
+        arc2.setCenterX(paneWidth / 2);
+        arc2.setCenterY(paneHeight - 40);
+        arc2.setRadiusX(paneWidth / 4);
+
+        line1.setStartX(paneWidth / 4);
+        line1.setEndX(paneWidth / 4);
+        line1.setEndY(paneHeight - 40);
+
+        line2.setStartX(paneWidth / 2 + paneWidth / 4);
+        line2.setEndX(paneWidth / 2 + paneWidth / 4);
+        line2.setEndY(paneHeight - 40);
+    }
+}

ch_15/Exercise15_24.java

@@ -0,0 +1,52 @@
+package ch_15;
+
+import javafx.animation.PathTransition;
+import javafx.animation.Timeline;
+import javafx.application.Application;
+import javafx.scene.Scene;
+import javafx.scene.Group;
+import javafx.scene.layout.BorderPane;
+import javafx.scene.paint.Color;
+import javafx.scene.shape.Arc;
+import javafx.scene.shape.Circle;
+import javafx.stage.Stage;
+import javafx.util.Duration;
+
+/**
+ * **15.24 (Animation: palindrome) Write a program that animates a palindrome swing as
+ * shown in Figure 15.31. Press/release the mouse to pause/resume the animation.
+ * <p>
+ * FIGURE 15.31 The program animates a palindrome swing.
+ */
+public class Exercise15_24 extends Application {
+    @Override
+    public void start(Stage primaryStage) {
+        Group group = new Group();
+        Circle circle = new Circle(0, 0, 10);
+        circle.setFill(Color.ORANGE);
+
+        Arc arc = new Arc(125, 100, 80, 40, 210, 125);
+        arc.setFill(Color.WHITE);
+        arc.setStroke(Color.BLACK);
+
+        group.getChildren().add(arc);
+        group.getChildren().add(circle);
+
+        PathTransition pt = new PathTransition();
+        pt.setDuration(Duration.millis(4000));
+        pt.setPath(arc);
+        pt.setNode(circle);
+        pt.setOrientation(
+                PathTransition.OrientationType.ORTHOGONAL_TO_TANGENT);
+        pt.setCycleCount(Timeline.INDEFINITE);
+        pt.setAutoReverse(true);
+        pt.play(); // Play animation
+
+        group.setOnMousePressed(e -> pt.pause());
+        group.setOnMouseReleased(e -> pt.play());
+        Scene scene = new Scene(new BorderPane(group), 250, 200);
+        primaryStage.setTitle(getClass().getName());
+        primaryStage.setScene(scene);
+        primaryStage.show();
+    }
+}

ch_15/Exercise15_26.java

@@ -0,0 +1,60 @@
+package ch_15;
+
+import javafx.animation.FadeTransition;
+import javafx.animation.PathTransition;
+import javafx.animation.Timeline;
+import javafx.application.Application;
+import javafx.scene.Scene;
+import javafx.scene.layout.Pane;
+import javafx.scene.paint.Color;
+import javafx.scene.shape.Arc;
+import javafx.scene.shape.Circle;
+import javafx.stage.Stage;
+import javafx.util.Duration;
+
+/**
+ * *15.26 (Change opacity) Rewrite Programming Exercise 15.24 so that the ball’s
+ * opacity is changed as it swings.
+ */
+public class Exercise15_26 extends Application {
+    @Override
+    public void start(Stage primaryStage) {
+        Pane pane = new Pane();
+
+        Circle circle = new Circle(0, 0, 10);
+        circle.setFill(Color.ORANGE);
+
+        Arc arc = new Arc(125, 100, 80, 40, 210, 125);
+        arc.setFill(Color.WHITE);
+        arc.setStroke(Color.BLACK);
+
+        pane.getChildren().add(arc);
+        pane.getChildren().add(circle);
+
+        PathTransition pt = new PathTransition();
+        pt.setDuration(Duration.millis(4000));
+        pt.setPath(arc);
+        pt.setNode(circle);
+        pt.setOrientation(
+                PathTransition.OrientationType.ORTHOGONAL_TO_TANGENT);
+        pt.setCycleCount(Timeline.INDEFINITE);
+        pt.setAutoReverse(true);
+        pt.play(); // Play path transition animation
+
+        FadeTransition ft = new FadeTransition(Duration.millis(3000), circle);
+        ft.setFromValue(1.0);
+        ft.setToValue(0.1);
+        ft.setCycleCount(Timeline.INDEFINITE);
+        ft.setAutoReverse(true);
+        ft.play(); // Play fade transition animation
+
+        pane.setOnMousePressed(e -> pt.pause());
+        pane.setOnMouseReleased(e -> pt.play());
+
+        Scene scene = new Scene(pane, 250, 200);
+        primaryStage.setTitle("Exercise15_26");
+        primaryStage.setScene(scene);
+        primaryStage.show();
+    }
+
+}