Chapter 14 Exercise 11, Introduction to Java Programming, Tenth Edition Y. Daniel LiangY.

14.11 (Paint a smiley face)
Write a program that paints a smiley face, as shown in
Figure 14.46a.

public class MyPoint {

    public double x;
    public double y;

    public MyPoint(double x, double y) {
        this.x = x;
        this.y = y;
    }

    public MyPoint() {
        this(0,0);
    }

    public double x() {
        return x;
    }

    public void setX(double x) {
        this.x = x;
    }

    public double y() {
        return y;
    }

    public void setY(double y) {
        this.y = y;
    }

    public double distance(double x, double y) {
        return Math.sqrt((this.x - x) * (this.x - x) + (this.y - y) * (this.y - y));
    }

    public double distance(MyPoint point) {

        return distance(point.x, point.y);
    }

    public MyPoint getCenterPoint(MyPoint p) {

        return new MyPoint((p.x + this.x) / 2, (p.y + this.y) / 2);
    }

    public static MyPoint getCenterPoint(double x1, double y1, double x2, double y2) {
        return new MyPoint((x1 + x2) / 2, (y1 + y2) / 2);
    }

    /** Return true if this point is on the left side of the
     *  directed line from p0 to p1 */
    public boolean leftOfTheLine(MyPoint p0, MyPoint p1) {

        return leftOfTheLine(p0.x, p0.y, p1.x, p1.y, x, y);
    }

    /** Return true if this point is on the same
     *  line from p0 to p1 */
    public boolean onTheSameLine(MyPoint p0, MyPoint p1) {

        return onTheSameLine(p0.x, p0.y, p1.x, p1.y, x, y);

    }

    /** Return true if this point is on the right side of the
     *  directed line from p0 to p1 */
    public boolean rightOfTheLine(MyPoint p0, MyPoint p1) {

        return rightOfTheLine(p0.x, p0.y, p1.x, p1.y, x, y);

    }

    /** Return true if this point is on the
     *  line segment from p0 to p1 */
    public boolean onTheLineSegment(MyPoint p0, MyPoint p1) {

        return onTheLineSegment(p0.x, p0.y, p1.x, p1.y, x, y);

    }


    /** Return true if point (x2, y2) is on the left side of the
     *  directed line from (x0, y0) to (x1, y1) */
    public static boolean leftOfTheLine(double x0, double y0, double x1, double y1, double x2, double y2){

        return (x1 - x0) * (y2 - y0) - (x2 - x0) * (y1 - y0) > 0;
    }
    /** Return true if point (x2, y2) is on the same
     *  line from (x0, y0) to (x1, y1) */
    public static boolean onTheSameLine(double x0, double y0, double x1, double y1, double x2, double y2) {

        return (x1 - x0) * (y2 - y0) - (x2 - x0) * (y1 - y0) == 0;
    }
    /** Return true if point (x2, y2) is on the
     *  line segment from (x0, y0) to (x1, y1) */
    public static boolean onTheLineSegment(double x0, double y0, double x1, double y1, double x2, double y2) {

        double position = (x1 - x0) * (y2 - y0) - (x2 - x0) * (y1 - y0);

        return position <= 0.0000000001 && ((x0 <= x2 && x2 <= x1) || (x0 >= x2 && x2 >= x1));
    }

    /** Return true if point (x2, y2) is on the right side of the
     *  directed line from (x0, y0) to (x1, y1) */
    public static boolean rightOfTheLine(double x0, double y0, double x1, double y1, double x2, double y2){

        return (x1 - x0) * (y2 - y0) - (x2 - x0) * (y1 - y0) < 0;
    }

    @Override
    public String toString() {
        return "(" + x + ", " + y + ")";
    }

}

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.shape.*;
import javafx.stage.Stage;

import java.util.ArrayList;
import java.util.Collections;
public class Exercise_11 extends Application {

    private static final int CENTER_Y = 200;
    private static final int CENTER_X = 200;
    private static final int RADIUS = 100;

    @Override
    public void start(Stage primaryStage) {

        Pane pane = new Pane();
        ArrayList<Shape> shapes = new ArrayList<>();

        // Outer circle of the smiley face
        Circle c = new Circle(CENTER_X, CENTER_Y, RADIUS, Color.TRANSPARENT);
        c.setStroke(Color.BLACK);
        shapes.add(c);

        // drawing the nose
        Line[] nose = createFixedNose(c);
        Collections.addAll(shapes, nose);

        // drawing left and right eye
        double y =  CENTER_Y - (RADIUS / 2.8);
        double x = CENTER_X - (RADIUS / 2.8);
        for (int i = 0; i < 2; i++) {
            Ellipse outerC = new Ellipse(x, y, RADIUS / 4, RADIUS / 6);
            outerC.setFill(Color.TRANSPARENT);
            outerC.setStroke(Color.BLACK);
            shapes.add(outerC);

            Circle pupil = new Circle(outerC.getCenterX(), outerC.getCenterY(), outerC.getRadiusY() / 1.2);
            shapes.add(pupil);
            x += (RADIUS / 2.8) * 2;
        }

        // drawing the face's smile
        Arc smile = new Arc(
                c.getCenterX(), // center x
                c.getCenterY() + (c.getRadius() / 3), // center y
                c.getRadius() / 2, // x radius
                c.getRadius() / 2 / 2, // y radius
                180, 180); // start point and length
        smile.setFill(Color.TRANSPARENT);
        smile.setStroke(Color.BLACK);
        shapes.add(smile);


        pane.getChildren().addAll(shapes);
        Scene scene = new Scene(pane, CENTER_X + RADIUS * 2, CENTER_Y + RADIUS * 2);
        primaryStage.setScene(scene);
        primaryStage.setTitle("Smiley Face!");
        primaryStage.show();
    }

    /**
     * returns 3 Lines that shape a fixed triangle based
     * from the circle's center point and radius
     * **/
    private Line[] createFixedNose(Circle c) {
        MyPoint p1 = new MyPoint(c.getCenterX() - (c.getRadius() / 4), c.getCenterY() + (c.getRadius() / 4));
        MyPoint p2 = new MyPoint(c.getCenterX() + (c.getRadius() / 4), c.getCenterY() + (c.getRadius() / 4));
        MyPoint p3 = new MyPoint(c.getCenterX(), c.getCenterY() - (c.getRadius() / 4));

        Line[] lines = new Line[3];
        lines[0] = new Line(p1.x, p1.y, p2.x, p2.y);
        lines[1] = new Line(p2.x, p2.y, p3.x, p3.y);
        lines[2] = new Line(p3.x, p3.y, p1.x, p1.y);

        return lines;
    }



    public static void main(String[] args) {
        Application.launch(args);
    }
}