// Mesh and Warp Canvas


import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.math.*;
import java.awt.geom.*;
import java.awt.image.*;
import java.io.*;
import javax.swing.*;
import javax.swing.event.*;
import com.sun.image.codec.jpeg.*;


public class MeshCanvas extends Canvas
             implements MouseListener, MouseMotionListener {

private int x;
private int y;
private boolean selected;		
private boolean firsttime;
private boolean showwarp=false;
private BufferedImage bim=null;
private BufferedImage bimwarp=null;
private Triangle S, T;
private int xsize, ysize;

private final int THRESHOLD_DISTANCE=10;

// constructor: creates an empty mesh point
public MeshCanvas () {
	setSize(getPreferredSize());
	addMouseListener(this);
	addMouseMotionListener(this);
	selected = false;
	firsttime=true;
}


// resets mesh point to center
public void clear() {
	selected = false;
	firsttime=true;
	showwarp=false;
	drawMesh();
}



public void mouseClicked(MouseEvent mevt) {
}
public void mouseEntered(MouseEvent mevt) {
}
public void mouseExited(MouseEvent mevt) {
}

// checks for user selecting the mesh control point within a threshold
// distance of the point

public void mousePressed(MouseEvent E) {
	int curx, cury;

	curx = E.getX();
	cury = E.getY();

	double distance = Math.sqrt((curx-x)*(curx-x)+(cury-y)*(cury-y));
	if (distance < THRESHOLD_DISTANCE){
	   selected=true;
           firsttime=false;
        }
}


// if a point is being dragged, the point is released
// otherwise, adds/removes a point at current position
public void mouseReleased(MouseEvent E) {

	// if a point was selected, it was just released
	if(selected) {
		selected = false;
	}
	makeWarp();
}


// if a point is selected, drag it
public void mouseDragged(MouseEvent E) {

	// if a point is selected, it's being moved
	// redraw (rubberbanding)
	if(selected) {
		x=E.getX();
		y=E.getY();
		drawMesh();
	}
}

public void mouseMoved(MouseEvent mevt) {
}


// draws the mesh on top of the background image
public void drawMesh() {
	repaint();
}

private BufferedImage readImage (String file) {

   Image image = Toolkit.getDefaultToolkit().getImage(file);
   MediaTracker tracker = new MediaTracker (new Component () {});
   tracker.addImage(image, 0);
   try { tracker.waitForID (0); }
   catch (InterruptedException e) {}
      BufferedImage bim = new BufferedImage 
          (image.getWidth(this), image.getHeight(this), 
          BufferedImage.TYPE_INT_RGB);
   Graphics2D big = bim.createGraphics();
   big.drawImage (image, 0, 0, this);
   return bim;
}

public void setImage(String file) {
   bim = readImage(file);
   setSize(new Dimension(bim.getWidth(), bim.getHeight()));
   this.repaint();
}

public void makeWarp() {

	if (bimwarp == null)
           bimwarp = new BufferedImage (bim.getWidth(this), 
                         bim.getHeight(this), 
                         BufferedImage.TYPE_INT_RGB);


	S = new Triangle (0, 0, xsize/2, ysize/2, xsize, 0);
	T = new Triangle (0, 0, x, y, xsize, 0);
	MorphTools.warpTriangle(bim, bimwarp, S, T, null, null);

	S = new Triangle (0, 0, 0, ysize, xsize/2, ysize/2);
	T = new Triangle (0, 0, 0, ysize, x, y);
	MorphTools.warpTriangle(bim, bimwarp, S, T, null, null);

	S = new Triangle (0, ysize, xsize, ysize, xsize/2, ysize/2);
	T = new Triangle (0, ysize, xsize, ysize, x, y);
	MorphTools.warpTriangle(bim, bimwarp, S, T, null, null);

	S = new Triangle (xsize, 0, xsize, ysize, xsize/2, ysize/2);
	T = new Triangle (xsize, 0, xsize, ysize, x, y);
	MorphTools.warpTriangle(bim, bimwarp, S, T, null, null);

	showwarp=true;
	this.repaint();
}

// Over-ride update method 
public void update(Graphics g) {
	paint(g);
}

// paints the polyline
public void paint (Graphics g) {

	// draw lines from each corner of canvas to the mesh point
	// with a circle at the mesh point

	xsize=getWidth();
	ysize=getHeight();

	if (firsttime) { x = xsize/2;  y = ysize/2; firsttime=false;}

	Graphics2D big = (Graphics2D) g;
	if (showwarp)
           big.drawImage(bimwarp, 0, 0, this);
	else {
           big.drawImage(bim, 0, 0, this);

	   g.drawLine(0,0,x,y);
	   g.drawLine(0,ysize,x,y);
	   g.drawLine(xsize,0,x,y);
	   g.drawLine(xsize,ysize,x,y);

	   // circle at point
	   g.fillOval(x-6, y-6, 12, 12);
	}

} // paint()


}