How to model a bending straw in JavaFX - user-interface

Question

My goal is to make it so that when a user slides a Slider, an object that is like a straw bends from its middle.
Sort of like this:
http://s.hswstatic.com/gif/bendy-straw-a-1.jpg
I've spent days searching for ways to model this with JavaFX shapes, but maybe I'm missing something obvious. When the Slider is at zero, the shape should be a straight line, whereas when the Slider is bent all the way, the shape should resemble an arm of a hyperbola.
Thank you so much.

Answer 1

You'll have to figure out the math correctly, but something like this is what I had in mind. You can even try just leaving the control point Y in the middle of the line, I moved it up since I figured it's more realistic, like it will start to bend at the bottom. You also have to do some calculus to figure out the end point. The length shouldn't change.
package curve;
import javafx.application.Application;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.Slider;
import javafx.scene.paint.Color;
import javafx.scene.shape.QuadCurve;
import javafx.stage.Stage;
public class Curve extends Application {
#Override
public void start(Stage primaryStage) {
QuadCurve qc = new QuadCurve(100, 500, 100, 250, 100, 0);
qc.setStroke(Color.BLUE);
qc.setStrokeWidth(5);
qc.setFill(Color.TRANSPARENT);
Slider slider = new Slider(0, 200, 0);
qc.endXProperty().bind(slider.valueProperty().add(100));
qc.endYProperty().bind(slider.valueProperty().add(100).divide(1.2));
qc.controlYProperty().bind(slider.valueProperty().multiply(-1).add(500));
Group group = new Group(qc,slider);
Scene scene = new Scene(group, 500,500);
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}