Click to draw a shape (circle) - javafx

Question

this code Draw a circle and I want to put a button that when I click on the button I can do draw a circle. How Can I put Button for code below?
import javafx.application.Application;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.stage.Stage;
public class HelloApplication extends Application {
private Circle circle;
private boolean firstClick = true;
private double centerX, centerY;
public static void main(String[] args) {
launch(args);
}
#Override
public void start(Stage primaryStage) throws Exception {
Group root = new Group();
circle = new Circle();
circle.setFill(Color.TRANSPARENT);
circle.setStroke(Color.BLACK);
root.getChildren().add(circle);
Scene scene = new Scene(root, 600, 600);
setHandlers(scene);
primaryStage.setTitle("blank");
primaryStage.setScene(scene);
primaryStage.show();
}
public void setHandlers(Scene scene) {
scene.setOnMouseClicked(e -> {
if (firstClick) {
centerX = e.getX();
centerY = e.getY();
// sets the center
circle.setCenterX(centerX);
circle.setCenterY(centerY);
// sets next "stage" of drawing your circle
firstClick = false;
// on second click will reset the process by setting firstClick to true
}
else {
firstClick = true;
}
});
scene.setOnMouseMoved(e -> {
// will only evaluate on the first instance of a click
if (!firstClick) {
// Distance formula between center of circle and mouse pointer
double c = Math
.sqrt(Math.pow(centerX - e.getX(), 2) + Math.pow(centerY - e.getY(), 2));
circle.setRadius(c);
}
});
}
}

Answer 1

The following mre demonstrates the basic functionality you required :
import javafx.application.Application;
import javafx.beans.value.ChangeListener;
import javafx.geometry.Pos;
import javafx.scene.*;
import javafx.scene.control.*;
import javafx.scene.input.MouseButton;
import javafx.scene.layout.*;
import javafx.scene.paint.Color;
import javafx.scene.shape.*;
import javafx.stage.Stage;
public class DrawCircles extends Application {
private Pane drawPane; //container for shapes
private Circle clickedPoint;
private static Color POINT_COLOR = Color.BLUEVIOLET, CIRCLE_COLOR = Color.RED;
private static int POINT_RADIUS = 2;
#Override
public void start(Stage primaryStage) {
BorderPane root = new BorderPane();
drawPane = new Pane(); //container for shapes
root.setCenter(drawPane);
Label help = new Label();
ToggleButton draw = new ToggleButton(" Draw ");
draw.selectedProperty().addListener((ChangeListener<Boolean>) (obs, oldV, newV) -> {
draw.setText(newV ? "Drawing" : " Draw ");
help.setText(newV ? "Double click on one point. Double click on second point" : "");
});
HBox buttonBar = new HBox(10, draw, help);
buttonBar.setAlignment(Pos.BOTTOM_LEFT);
root.setBottom(buttonBar);
drawPane.setOnMouseClicked(event -> {
if(!draw.isSelected()) return;
if (event.getButton().equals(MouseButton.PRIMARY) && event.getClickCount() == 2) {
addPoint( event.getX() , event.getY());
}
});
Scene scene = new Scene(root, 500, 500);
primaryStage.setScene(scene);
primaryStage.setTitle("Draw Circles");
primaryStage.show();
}
private void addPoint(double x, double y) {
if(clickedPoint == null){ //no previously clicked point
clickedPoint = new Circle(x, y, POINT_RADIUS, POINT_COLOR);
drawPane.getChildren().add(clickedPoint); //mark clicked point
}else{
Shape shape = makeCircle(clickedPoint.getCenterX(), clickedPoint.getCenterY(), x, y);
drawPane.getChildren().add(shape); //add line
drawPane.getChildren().remove(clickedPoint);// remove first clicked point
clickedPoint = null;
}
}
private Shape makeCircle(double xCenter, double yCenter, double xEdge, double yEdge){
double radius =Math.sqrt( Math.pow(xEdge - xCenter, 2) + Math.pow(yEdge - yCenter, 2));
return new Circle(xCenter, yCenter, radius, CIRCLE_COLOR);
}
public static void main(String[] args) {
launch(args);
}
}