Pages

Wednesday, 21 September 2016

Chapter 10 Exercise 15, Introduction to Java Programming, Tenth Edition Y. Daniel LiangY.

Chapter 10 Exercise 15:
"*10.15 (Geometry: the bounding rectangle)
A bounding rectangle is the minimum rectangle that encloses a set of points in a two-dimensional
plane, as shown in Figure 10.24d. Write a method that returns a bounding rectangle for a set of
points in a two-dimensional plane, as follows:"
 *
"public  static  MyRectangle2D  getRectangle(double[][]  points)"
"The Rectangle2D class is defined in Programming Exercise 10.13. Write a"
"test program that prompts the user to enter five points and displays the bounding
rectangle’s center, width, and height. Here is a sample run:"
 *
"Enter five points: 1.0 2.5 3 4 5 6 7 8 9 10"
"The bounding rectangle's center (5.0, 6.25), width 8.0, height 7.5"

import javafx.scene.shape.Rectangle;
public class MyRectangle2D extends GeometricObject {

    private static final int X = 0;
    private static final int Y = 1;

    public double centerX;
    public double centerY;

    public double width;
    public double height;

    public MyRectangle2D(double centerX, double centerY, double width, double height) {
        this.centerX = centerX;
        this.centerY = centerY;
        this.width = width;
        this.height = height;
    }

    public MyRectangle2D(MyPoint centerPoint, double width, double height) {
        this(centerPoint.x, centerPoint.y, width, height);
    }

    public MyRectangle2D(Rectangle rectangle) {
        this(rectangle.getX(), rectangle.getY(), rectangle.getWidth(), rectangle.getHeight());
    }

    public MyRectangle2D() {
        this(0, 0, 1, 1);
    }

    public MyPoint getCenterP() {
        return new MyPoint(centerX, centerY);
    }
    public MyPoint getP1() {
        return new MyPoint(centerX - width / 2, centerY + height / 2);
    }

    public MyPoint getP2() {
        return new MyPoint(centerX + width / 2, centerY + height / 2);
    }

    public MyPoint getP3() {
        return new MyPoint(centerX - width / 2, centerY - height / 2);
    }

    public MyPoint getP4() {
        return new MyPoint(centerX + width / 2, centerY - height / 2);
    }

    public double getCenterX() {
        return centerX;
    }

    public void setCenterX(double centerX) {
        this.centerX = centerX;
    }

    public double getCenterY() {
        return centerY;
    }

    public void setCenterY(double centerY) {
        this.centerY = centerY;
    }

    public double getWidth() {
        return width;
    }

    public void setWidth(double width) {
        this.width = width;
    }

    public double getHeight() {
        return height;
    }

    public void setHeight(double height) {
        this.height = height;
    }

    /** returns the perimeter of the rectangle. **/
    @Override
    public double getPerimeter() {

        return width * 2 + height * 2;
    }

    /** returns the area of the rectangle **/
    @Override
    public double getArea() {
        return width * height;
    }

    public boolean contains(double x, double y) {

        // Get max X & Y
        double maxX = getMax(getP1().x, getP2().x, getP3().x, getP4().x);
        double maxY = getMax(getP1().y, getP2().y, getP3().y, getP4().y);
        // Get min X & Y
        double minX = getMin(getP1().x, getP2().x, getP3().x, getP4().x);
        double minY = getMin(getP1().y, getP2().y, getP3().y, getP4().y);

        if (x < minX || x > maxX || y < minY || y > maxY)  return false;

        return true;

    }

    public boolean contains(MyRectangle2D r2) {
        double xDistance = (r2.centerX > centerX) ? r2.centerX - centerX : centerX - r2.centerX;
        double yDistance = (r2.centerY > centerY) ? r2.centerY - centerY : centerY - r2.centerY;

        // if the r2 is inside this rectangle
        // this is only valid if the rectangles are parallel
        return (xDistance <= (width - r2.width) / 2 && yDistance <= (height - r2.height) / 2);

    }

    public boolean overlaps(MyRectangle2D r2) {
        // subtract from the highest number
        double xDistance = (r2.centerX > centerX) ? r2.centerX - centerX : centerX - r2.centerX;
        double yDistance = (r2.centerY > centerY) ? r2.centerY - centerY : centerY - r2.centerY;

        // if the r2 overlaps this rectangle
        // this is only valid if the rectangles are parallel
        return (xDistance <= (width + r2.width) / 2 && yDistance <= (height + r2.height) / 2);

    }

    public static boolean r1OverLapsR2(Rectangle r1, Rectangle r2) {
        return r1.intersects(r2.getBoundsInLocal()) || r2.intersects(r1.getBoundsInLocal());
    }

    public javafx.scene.shape.Rectangle getRectangle() {
        return new Rectangle(centerX, centerY, width, height);
    }
    public boolean contains(MyPoint[] points) {

        for (MyPoint p : points) {
            if (!contains(p)) return false;
        }
        return true;
    }

    public boolean contains(MyPoint point) {
        return contains(point.x, point.y);
    }

    public static MyRectangle2D getRectangle(double[][] points) {

        // find leftLowestPoint

        // find rightMostPoint

        // find the center from highest and lowest point

        // x distance = width

        // y distance = height
        MyPoint[] myPoints = new MyPoint[points.length];
        for (int i = 0; i < points.length; i++) {
            myPoints[i] = new MyPoint(points[i][0], points[i][1]);
        }

        return getRectangle(myPoints);
    }

    public static MyRectangle2D getRectangle(MyPoint[] points) {

        MyPoint leftMost = getLeftMostPoint(points);
        MyPoint rightMost = getRighMostPoint(points);
        double width = Math.abs(rightMost.x - leftMost.x);

        MyPoint highest = getHighestPoint(points);
        MyPoint lowest = getLowestPoint(points);
        double height = Math.abs(highest.y - lowest.y);

        double centerX = highest.getCenterPoint(lowest).x;
        double centerY = leftMost.getCenterPoint(rightMost).y;

        return new MyRectangle2D(centerX, centerY, width, height);
    }

    private static MyPoint getLeftMostPoint(MyPoint[] points) {

        MyPoint leftMost = points[0];
        for (int i = 0; i < points.length; i++) {
            if (leftMost.x > points[i].x) {
                leftMost = points[i];
            }
        }
        return leftMost;
    }

    private static MyPoint getRighMostPoint(MyPoint[] points) {

        MyPoint rightMost = points[0];
        for (int i = 0; i < points.length; i++) {
            if (rightMost.x < points[i].x) {
                rightMost = points[i];
            }
        }
        return rightMost;
    }

    private static MyPoint getHighestPoint(MyPoint[] points) {

        MyPoint highest = points[0];
        for (int i = 0; i < points.length; i++) {
            if (highest.y < points[i].y) {
                highest = points[i];
            }
        }
        return highest;
    }

    private static MyPoint getLowestPoint(MyPoint[] points) {

        MyPoint lowest = points[0];
        for (int i = 0; i < points.length; i++) {
            if (lowest.y > points[i].y) {
                lowest = points[i];
            }
        }
        return lowest;
    }

    private double getMax(double... n) {
        double max = n[0];
        for (int i = 1; i < n.length; i++) {
            if (max < n[i]) {
                max = n[i];
            }
        }
        return max;
    }
    private double getMin(double... n) {
        double min = n[0];
        for (int i = 1; i < n.length; i++) {
            if (min > n[i]) {
                min = n[i];
            }
        }
        return min;
    }

    @Override
    public String toString() {
        return "MyRectangle2D{" +
                "centerX=" + centerX +
                ", centerY=" + centerY +
                ", width=" + width +
                ", height=" + height +
                '}';
    }
}

import java.util.Scanner;
public class Exercise_15 {

    public static void main(String[] args) {

        // 1.0 2.5 3 4 5 6 7 8 9 10
        System.out.print("Enter 5 given points: ");
        Scanner input = new Scanner(System.in);
        double[][] points = new double[5][2];
        for (int i = 0; i < points.length; i++) {
            points[i][0] = input.nextDouble();
            points[i][1] = input.nextDouble();
        }

        MyRectangle2D r1 = MyRectangle2D.getRectangle(points);
        System.out.println("Center point: " + r1.getCenterP().toString());
        System.out.println("width = " + r1.getWidth());
        System.out.println("height = " + r1.getHeight());
    }
}

2 comments :

  1. Hi thanks for your solutions.
    Do you write solutions yourself?

    ReplyDelete
  2. Thank you i research a lot and write solutions.

    ReplyDelete