Question

Write Java Program.

(Plot the sine and cosine functions) Write a program that plots the sine function in red and cosine in blue, as shown in Figure 14.48c.

Hint: The Unicode for P is u03c0. To display -2p, use Text(x, y, "-2\u03c0"). For a trigonometric function like sin(x), x is in radians. Use the following loop to add the points to a polyline:

Polyline polyline = new polyline ();

ObservableList<Double> list = polyline.getPoints ();

double scaleFactor = 50;

for (int x = -170; x <= 170; x++){

list.add(x + 200.0);

list.add(100 - 50 * Math.sin((x / 100.0) * 2 * Math.PI));

}

Answer 1

import javafx.application.Application;
import javafx.collections.ObservableList;
import javafx.scene.Scene;
import javafx.scene.layout.Pane;
import javafx.scene.shape.Line;
import javafx.scene.shape.Polyline;
import javafx.scene.text.Font;
import javafx.scene.text.Text;
import javafx.stage.Stage;

public class Exercise_19 extends Application{

private static double WIDTH = 500;
private static double HEIGHT = 200;
private static double CENTER_X = WIDTH / 2;
private static double CENTER_Y = HEIGHT / 2;

@Override
public void start(Stage primaryStage) throws Exception {
Pane pane = new Pane();

Polyline xAxis = new Polyline();
drawXAxis(pane, xAxis);
Polyline yAxis = new Polyline();
drawYAxis(pane, yAxis);

String[] pi = new String[] {"-3\u03c0", "-2\u03c0", "-\u03c0", "0" , "\u03c0", "2\u03c0", "3\u03c0"};

int index = 0;
Polyline polyline1 = new Polyline();
ObservableList<Double> list = polyline1.getPoints();
for (int x = -170; x <= 170; x++) {
list.add(x + CENTER_X);
double y = CENTER_Y - 50 * Math.sin((x / 100.0) * 2 * Math.PI);
list.add(y);

if (y >= 99.9 && y < 100.01) {
Text text1 = new Text(x + CENTER_X, CENTER_Y / 0.9, pi[index++]);
pane.getChildren().add(text1);
}

}
Polyline polyline2 = new Polyline();
ObservableList<Double> list2 = polyline2.getPoints();

for (int x = -170; x <= 170; x++) {
list2.add(x + CENTER_X);
list2.add(CENTER_Y - 50 * Math.cos((x / 100.0) * 2 * Math.PI));

}
pane.getChildren().addAll(xAxis, yAxis,polyline1,polyline2);
primaryStage.setScene(new Scene(pane, WIDTH, HEIGHT));
primaryStage.setTitle("Plot the sine and cosine functions");
primaryStage.show();

}

private static void drawXAxis(Pane pane, Polyline xAxis) {
ObservableList<Double> xAxisList = xAxis.getPoints();
double limit = WIDTH * 0.95;

for (double x = 0; x < limit; x++) {
xAxisList.add(x);
xAxisList.add(CENTER_Y);
}

Line line1 = new Line(limit, CENTER_Y, limit - WIDTH * 0.05, CENTER_Y * 0.875);
Line line2 = new Line(limit, CENTER_Y, limit - WIDTH * 0.05, CENTER_Y / 0.875);
Text text = new Text(limit + (WIDTH * 0.02), CENTER_Y, "X");
text.setFont(Font.font(22));
pane.getChildren().addAll(line1, line2, text);
}

private static void drawYAxis(Pane pane, Polyline yAxis) {

ObservableList<Double> yAxisList = yAxis.getPoints();
double limit = HEIGHT * 0.95;

for (double y = 0; y < limit; y++) {
yAxisList.add(CENTER_X);
yAxisList.add(y + HEIGHT * 0.1);

}
Line line1 = new Line(CENTER_X, HEIGHT * 0.1, CENTER_X - WIDTH * 0.05, HEIGHT * 0.2);
Line line2 = new Line(CENTER_X, HEIGHT * 0.1, CENTER_X + WIDTH * 0.05, HEIGHT * 0.2);
Text text = new Text(limit + (WIDTH * 0.2), HEIGHT * 0.1, "Y");
text.setFont(Font.font(22));
pane.getChildren().addAll(line1, line2,text);
}

public static void main(String[] args) {

Application.launch(args);

}

}