import java.applet.*;
import java.awt.*;
import java.awt.event.*;
public class Bezier extends Applet implements MouseListener, MouseMotionListener, Runnable
{
double[] [] point = new double [5] [2];
int dragged;
Thread t;
Graphics b;
Image offscreen;
int mode;
public void init ()
{
mode = 3;
dragged = -1;
for (int i = 0 ; i < point.length ; i++)
{
point [i] [0] = (int) (Math.random () * 800);
point [i] [1] = (int) (Math.random () * 600);
}
setFocusable (true);
addMouseListener (this);
addMouseMotionListener (this);
t = new Thread (this);
t.start ();
offscreen = createImage (800, 600);
b = offscreen.getGraphics ();
} // init method
public void update (Graphics g)
{
paint (g);
}
public void run ()
{
while (true)
{
repaint ();
try
{
t.sleep (10);
}
catch (InterruptedException e)
{
}
}
}
public void paint (Graphics g)
{
b.setColor (Color.white); //clears the buffer
b.fillRect (0, 0, 800, 600);
b.setColor (Color.red);
b.fillRect (0, 0, 100, 30);
b.setColor (Color.black);
switch (mode)
{
case 1:
b.drawString ("Adding nodes", 10, 20);
break;
case 2:
b.drawString ("Deleting nodes", 10, 20);
break;
case 3:
b.drawString ("Moving nodes", 10, 20);
break;
}
for (int i = 0 ; i < point.length ; i++)
{
b.fillOval ((int) (point [i] [0] - 10), (int) (point [i] [1] - 10), 20, 20);
}
b.setColor (Color.blue);
for (int i = 0 ; i < point.length - 1 ; i++)
{
b.drawLine ((int) (point [i] [0]), (int) (point [i] [1]), (int) (point [i + 1] [0]), (int) (point [i + 1] [1]));
}
double[] current = new double [2];
b.setColor (Color.green);
for (double t = 0 ; t <= 1 ; t += 0.0005)
{
current = Bez (t, point);
b.fillOval ((int) current [0] - 2, (int) current [1] - 2, 4, 4);
}
g.drawImage (offscreen, 0, 0, this);
} // paint method
public double[] Bez (double t, double[] [] point)
{
if (point.length == 1 /*|| t < 0 || t > 1*/)
{
double[] New = new double [2];
New [0] = point [0] [0];
New [1] = point [0] [1];
return New;
}
double[] [] New = new double [point.length - 1] [2];
for (int i = 0 ; i < New.length ; i++)
{
New [i] [0] = ((1 - t) * point [i] [0]) + (t * point [i + 1] [0]);
New [i] [1] = ((1 - t) * point [i] [1]) + (t * point [i + 1] [1]);
}
return Bez (t, New);
}
public void mouseClicked (MouseEvent e)
{
}
public void mouseMoved (MouseEvent e)
{
}
public void mouseReleased (MouseEvent e)
{
dragged = -1;
}
public void mouseEntered (MouseEvent e)
{
}
public void mouseExited (MouseEvent e)
{
}
public void mousePressed (MouseEvent e)
{
if (e.getX () >= 0 && e.getX () <= 100 && e.getY () >= 0 && e.getY () <= 30)
{ // red button was clicked
switch (mode)
{
case 1:
mode = 2;
break;
case 2:
mode = 3;
break;
case 3:
mode = 1;
break;
} // switch (mode)
} // if (e.getX () >= 0 && e.getX () <= 100 && e.getY () >= 0 && e.getY () <= 30)
// mode: 1=add; 2=delete; 3=move
else if (mode == 1)
{
dragged = -1;
double[] [] temp = point;
point = new double [temp.length + 1] [2];
for (int i = 0 ; i < temp.length ; i++)
{
point [i] [0] = temp [i] [0];
point [i] [1] = temp [i] [1];
} // for (int i = 0 ; i < temp.length ; i++)
point [point.length - 1] [0] = e.getX ();
point [point.length - 1] [1] = e.getY ();
} // if (mode == 1)
else if (mode == 2)
{
dragged = -1;
for (int i = 0 ; i < point.length ; i++)
{
if (Dist ((double) e.getX (), (double) e.getY (), point [i] [0], point [i] [1]) <= 10)
{ // delete this index
for (int j = i ; j < point.length - 1 ; j++)
{
point [j] [0] = point [j + 1] [0];
point [j] [1] = point [j + 1] [1];
} // for (int j = i ; j < point.length ; j++)
double[] [] temp = point;
point = new double [temp.length - 1] [2];
for (int j = 0 ; j < point.length ; j++)
{
point [j] [0] = temp [j] [0];
point [j] [1] = temp [j] [1];
} // for (int j = 0 ; j < point.length ; j++)
} // if (Dist ((double) e.getX (), (double) e.getY (), point [i] [0], point [i] [1]) <= 10)
} // for (int i = 0 ; i <= point.length ; i++)
} // else if (mode == 2)
else if (mode == 3)
{
for (int i = 0 ; i <= point.length ; i++)
{
try
{
if (Dist ((double) e.getX (), (double) e.getY (), point [i] [0], point [i] [1]) <= 10)
{
dragged = i;
} // if (Dist ((double) e.getX (), (double) e.getY (), point [i] [0], point [i] [1]) <= 10)
} // try
catch (Exception ex)
{
} // catch (Exception ex)
} // for (int i = 0 ; i <= point.length ; i++)
}
}
public double Dist (double x1, double y1, double x2, double y2)
{
return Math.pow (Math.pow (x2 - x1, 2) + Math.pow (y2 - y1, 2), 0.5);
}
public void mouseDragged (MouseEvent e)
{
if (dragged != -1)
{
point [dragged] [0] = e.getX ();
point [dragged] [1] = e.getY ();
}
}
}
