EXERCISE_15_21_Solution

[erenkrabulut]

 package exc_15_21;

import java.util.ArrayList;
import javafx.application.Application;
import javafx.collections.ObservableList;
import javafx.scene.Scene;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.scene.shape.Polygon;
import javafx.scene.text.Text;
import javafx.stage.Stage;

public class Exc_15_21 extends Application {
 Pane pane = new Pane();
 
 Circle circle = new Circle(200,200,100); 
 Circle outerCircle = new Circle(200,200,112);
 Circle innerCircle = new Circle(200,200,88);
 
 @Override 
 public void start(Stage primaryStage){
 circle.setFill(Color.WHITE);
 circle.setStroke(Color.BLACK);
 
 pane.getChildren().add(circle);
 
 double angle1 = Math.toRadians(Math.random()*360);
 double x1 = circle.getCenterX() + (circle.getRadius()*Math.cos(angle1));
 double y1 = circle.getCenterY() - (circle.getRadius()*Math.sin(angle1));
 double angle2 = Math.toRadians(Math.random()*360);
 double x2 = circle.getCenterX() + (circle.getRadius()*Math.cos(angle2));
 double y2 = circle.getCenterY() - (circle.getRadius()*Math.sin(angle2));
 double angle3 = Math.toRadians(Math.random()*360);
 double x3 = circle.getCenterX() + (circle.getRadius()*Math.cos(angle3));
 double y3 = circle.getCenterY() - (circle.getRadius()*Math.sin(angle3));
 
 ArrayList<Circle> circles = new ArrayList<>();
 Circle c1 = new Circle(x1,y1,12);
 Circle c2 = new Circle(x2,y2,12);
 Circle c3 = new Circle(x3,y3,12);
 circles.add(c1);
 circles.add(c2);
 circles.add(c3);

 display(circles);
 
 pane.setOnMouseDragged(e -> {
 for(int i=0 ; i< circles.size(); i++)
 {
 if(circles.get(i).contains(e.getX(),e.getY()))
 {
 if( outerCircle.contains(e.getX(),e.getY()) && !innerCircle.contains(e.getX(),e.getY()) )
 {
 double[] pointsOnCircle = getPoints(e.getX(),e.getY());
 circles.get(i).setCenterX(pointsOnCircle[0]);
 circles.get(i).setCenterY(pointsOnCircle[1]);
 display(circles);
 } 
 }
 }
 });
 
 primaryStage.setScene(new Scene(pane,400,400));
 primaryStage.setTitle("Exc_15_21");
 primaryStage.show(); 
 }
 
 public double[] getPoints( double x, double y)
 {
 double angle = (Math.atan((y-circle.getCenterY())/(x-circle.getCenterX())));
 angle *= -1;
 if(circle.getCenterX()>x)
 {
 angle +=Math.PI;
 
 }
 return new double[]{circle.getCenterX() + (circle.getRadius() * Math.cos(angle)) , circle.getCenterY() - (circle.getRadius() * Math.sin(angle))};
 }
 
 public ArrayList<Double> getSides(ArrayList<Circle> p)
 {
 ArrayList<Double> sides = new ArrayList<>();
 sides.add(Math.sqrt(Math.pow(p.get(0).getCenterX() - p.get(1).getCenterX(), 2) + Math.pow(p.get(0).getCenterY() - p.get(1).getCenterY(), 2)));
 sides.add(Math.sqrt(Math.pow(p.get(1).getCenterX() - p.get(2).getCenterX(), 2) + Math.pow(p.get(1).getCenterY() - p.get(2).getCenterY(), 2)));
 sides.add(Math.sqrt(Math.pow(p.get(2).getCenterX() - p.get(0).getCenterX(), 2) + Math.pow(p.get(2).getCenterY() - p.get(0).getCenterY(), 2)));
 return sides;
 }
 
 public ArrayList<Double> getAngles(ArrayList<Double> sides)
 {
 ArrayList<Double> angles = new ArrayList<>();
 angles.add(Math.toDegrees(Math.acos((sides.get(0) * sides.get(0) - sides.get(1) * sides.get(1) - sides.get(2) * sides.get(2)) / (-2 * sides.get(1) * sides.get(2))))); 
 angles.add(Math.toDegrees(Math.acos((sides.get(1) * sides.get(1) - sides.get(0) * sides.get(0) - sides.get(2) * sides.get(2)) / (-2 * sides.get(0) * sides.get(2))))); 
 angles.add(Math.toDegrees(Math.acos((sides.get(2) * sides.get(2) - sides.get(1) * sides.get(1) - sides.get(0) * sides.get(0)) / (-2 * sides.get(0) * sides.get(1))))); 
 return angles;
 }
 
 public void display(ArrayList<Circle> circles)
 {
 pane.getChildren().clear();
 pane.getChildren().add(circle);
 Polygon triangle = new Polygon();
 ObservableList<Double> points = triangle.getPoints();
 for(int i=0 ; i<circles.size(); i++)
 {
 points.add(circles.get(i).getCenterX());
 points.add(circles.get(i).getCenterY());
 }
 triangle.setStroke(Color.BLACK);
 triangle.setFill(Color.WHITE);
 pane.getChildren().add(triangle);
 
 ArrayList<Double> angles = getAngles(getSides(circles));
 
 for(int i=0 ; i<circles.size(); i++)
 {
 pane.getChildren().add(circles.get(i));
 pane.getChildren().add(new Text( circles.get(i).getCenterX()+5 , circles.get(i).getCenterY()-18 , String.format("%.2f", angles.get(i))));
 }
 
 
 }
}