MainClass.java Source code

Introduction

Here is the source code for MainClass.java

Source

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.MouseEvent;
import java.awt.geom.CubicCurve2D;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Line2D;
import java.awt.geom.Point2D;
import java.awt.geom.QuadCurve2D;

import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.event.MouseInputAdapter;

public class MainClass {
    public static void main(String[] args) {
        JFrame frame = new JFrame();
        frame.getContentPane().add(new CurveApplet());

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(200, 200);
        frame.setVisible(true);
    }
}

class CurveApplet extends JPanel {
    public CurveApplet() {
        super(new BorderLayout());
        pane = new CurvePane();
        add(pane, "Center");

        MouseHandler handler = new MouseHandler();
        pane.addMouseListener(handler);
        pane.addMouseMotionListener(handler);
    }

    class CurvePane extends JComponent {
        public CurvePane() {
            quadCurve = new QuadCurve2D.Double(startQ.x, startQ.y, control.x, control.y, endQ.x, endQ.y);

            cubicCurve = new CubicCurve2D.Double(startC.x, startC.y, controlStart.x, controlStart.y, controlEnd.x,
                    controlEnd.y, endC.x, endC.y);
        }

        public void paint(Graphics g) {
            Graphics2D g2D = (Graphics2D) g;
            quadCurve.ctrlx = ctrlQuad.getCenter().x;
            quadCurve.ctrly = ctrlQuad.getCenter().y;
            cubicCurve.ctrlx1 = ctrlCubic1.getCenter().x;
            cubicCurve.ctrly1 = ctrlCubic1.getCenter().y;
            cubicCurve.ctrlx2 = ctrlCubic2.getCenter().x;
            cubicCurve.ctrly2 = ctrlCubic2.getCenter().y;

            g2D.setPaint(Color.BLUE);
            g2D.draw(quadCurve);
            g2D.draw(cubicCurve);

            g2D.setPaint(Color.RED);
            ctrlQuad.draw(g2D);
            ctrlCubic1.draw(g2D);
            ctrlCubic2.draw(g2D);

            Line2D.Double tangent = new Line2D.Double(startQ, ctrlQuad.getCenter());
            g2D.draw(tangent);
            tangent = new Line2D.Double(endQ, ctrlQuad.getCenter());
            g2D.draw(tangent);

            tangent = new Line2D.Double(startC, ctrlCubic1.getCenter());
            g2D.draw(tangent);
            tangent = new Line2D.Double(endC, ctrlCubic2.getCenter());
            g2D.draw(tangent);

        }
    }

    Point2D.Double startQ = new Point2D.Double(50, 75);

    Point2D.Double endQ = new Point2D.Double(150, 75);

    Point2D.Double control = new Point2D.Double(80, 25);

    Point2D.Double startC = new Point2D.Double(50, 150);

    Point2D.Double endC = new Point2D.Double(150, 150);

    Point2D.Double controlStart = new Point2D.Double(80, 100);

    Point2D.Double controlEnd = new Point2D.Double(160, 100);

    Marker ctrlQuad = new Marker(control);

    Marker ctrlCubic1 = new Marker(controlStart);

    Marker ctrlCubic2 = new Marker(controlEnd);

    QuadCurve2D.Double quadCurve;

    CubicCurve2D.Double cubicCurve;

    CurvePane pane = new CurvePane();

    class Marker {
        public Marker(Point2D.Double control) {
            center = control;
            circle = new Ellipse2D.Double(control.x - radius, control.y - radius, 2.0 * radius, 2.0 * radius);
        }

        public void draw(Graphics2D g2D) {
            g2D.draw(circle);
        }

        Point2D.Double getCenter() {
            return center;
        }

        public boolean contains(double x, double y) {
            return circle.contains(x, y);
        }

        public void setLocation(double x, double y) {
            center.x = x;
            center.y = y;
            circle.x = x - radius;
            circle.y = y - radius;
        }

        Ellipse2D.Double circle;

        Point2D.Double center;

        static final double radius = 3;
    }

    class MouseHandler extends MouseInputAdapter {
        public void mousePressed(MouseEvent e) {
            if (ctrlQuad.contains(e.getX(), e.getY()))
                selected = ctrlQuad;
            else if (ctrlCubic1.contains(e.getX(), e.getY()))
                selected = ctrlCubic1;
            else if (ctrlCubic2.contains(e.getX(), e.getY()))
                selected = ctrlCubic2;
        }

        public void mouseReleased(MouseEvent e) {
            selected = null;
        }

        public void mouseDragged(MouseEvent e) {
            if (selected != null) {
                selected.setLocation(e.getX(), e.getY());
                pane.repaint();
            }
        }

        Marker selected = null;
    }
}