/*
 * Harriet Fell, Northeastern University, August 2006
 */
import java.awt.*;
import java.awt.geom.Point2D;
import java.lang.Math;

public class bezier extends BufferedApplet
// based of Perlin's bspline
{
	int w = 1, h; 
	Color lightGreen = new Color(160,255,160);
	
	// Default Arch Points
	Point2D.Double P = new Point2D.Double(.125, .5);
	Point2D.Double Q = new Point2D.Double(.375, .25);
	Point2D.Double R = new Point2D.Double(.675, .25);
	Point2D.Double S = new Point2D.Double(.875, .5);
	
	int dtSz = 7; // dot size
	
	boolean newP = false, newQ = false, newR = false, newS = false;
	
	public void render(Graphics g) {
		w = bounds().width;                 // FETCH APPLET WIDTH,HT
		h = bounds().height;
		g.setColor(Color.white);            // FILL BACKGROUND
		g.fillRect(0,0,w,h);

		// Scale to Window Size
		Point2D.Double Pd = new Point2D.Double(w*P.getX(), h*P.getY()); 
		Point2D.Double Qd = new Point2D.Double(w*Q.getX(), h*Q.getY());  
		Point2D.Double Rd = new Point2D.Double(w*R.getX(), h*R.getY()); 
		Point2D.Double Sd = new Point2D.Double(w*S.getX(), h*S.getY()); 
		
		showArch(g, Pd, Qd, Rd, Sd);
	}
	
	public void showArch(Graphics g, Point2D.Double P, Point2D.Double Q, Point2D.Double R, Point2D.Double S){
		// Draw Arch Lines
		g.setColor(lightGreen);
		g.drawLine((int)P.getX(), (int)P.getY(), (int)Q.getX(), (int)Q.getY());
		g.drawLine((int)Q.getX(), (int)Q.getY(), (int)R.getX(), (int)R.getY());
		g.drawLine((int)R.getX(), (int)R.getY(), (int)S.getX(), (int)S.getY());
		
		// Draw Bezier Curve
		g.setColor(Color.black);
		drawArch(g, P, Q, R, S);
		
		// Draw Arch Points
		g.setColor(Color.red);
		g.fillOval((int)P.getX()-dtSz,(int)P.getY()-dtSz,2*dtSz,2*dtSz); 
		g.fillOval((int)Q.getX()-dtSz,(int)Q.getY()-dtSz,2*dtSz,2*dtSz);
		g.fillOval((int)R.getX()-dtSz,(int)R.getY()-dtSz,2*dtSz,2*dtSz);
		g.fillOval((int)S.getX()-dtSz,(int)S.getY()-dtSz,2*dtSz,2*dtSz);
	}
	
	public void drawArch(Graphics g, Point2D.Double P, Point2D.Double Q, Point2D.Double R, Point2D.Double S){
		if (ArchSize(P, Q, R, S) <= .5 ) g.drawLine((int) P.getX(), (int) P.getY(), (int) S.getX(), (int) S.getY());
		else{
			Point2D.Double PQ, QR, RS, PQR, QRS, PQRS;
			PQ = new Point2D.Double((P.getX() + Q.getX())/2, (P.getY() + Q.getY())/2);
			QR = new Point2D.Double((Q.getX() + R.getX())/2, (Q.getY() + R.getY())/2);
			RS = new Point2D.Double((R.getX() + S.getX())/2, (R.getY() + S.getY())/2);
			
			PQR = new Point2D.Double((PQ.getX() + QR.getX())/2, (PQ.getY() + QR.getY())/2);
			QRS = new Point2D.Double((QR.getX() + RS.getX())/2, (QR.getY() + RS.getY())/2);
			
			PQRS = new Point2D.Double((PQR.getX() + QRS.getX())/2, (PQR.getY() + QRS.getY())/2);
			
			drawArch(g,P, PQ, PQR, PQRS);
			drawArch(g, PQRS, QRS, RS, S);
		}
	}
	
	double ArchSize(Point2D.Double P, Point2D.Double Q, Point2D.Double R, Point2D.Double S){
		double xmin = P.getX(), ymin = P.getY();
		double xmax = P.getX(), ymax = P.getY();
		
		if (Q.getX() < xmin) xmin = Q.getX(); else if (Q.getX() > xmax) xmax = Q.getX();
		if (Q.getY() < ymin) ymin = Q.getY(); else if (Q.getY() > ymax) ymax = Q.getY();
		if (R.getX() < xmin) xmin = Q.getX(); else if (R.getX() > xmax) xmax = R.getX();
		if (R.getY() < ymin) ymin = R.getY(); else if (R.getY() > ymax) ymax = R.getY();
		if (S.getX() < xmin) xmin = S.getX(); else if (S.getX() > xmax) xmax = S.getX();
		if (S.getY() < ymin) ymin = S.getY(); else if (S.getY() > ymax) ymax = S.getY();
		if (xmax - xmin > ymax - ymin)
			return (xmax - xmin);
		else
			return (ymax - ymin);
	}
	
	int mode;
	public boolean keyUp(Event e, int key) {
		mode = key;
		damage = true;
		return true;
	}
	
	public boolean mouseDown(Event e, int x, int y) {
		//System.out.println(P.toString());
		//System.out.println((double)x/w + " " + (double)y/h);
		if 
		((w*P.getX()-x)*(w*P.getX()-x) + (h*P.getY()-y)*(h*P.getY()-y) <= dtSz*dtSz) {
			newP = true; newQ = false; newR = false; newS = false;
		} else if 
		((w*Q.getX()-x)*(w*Q.getX()-x) + (h*Q.getY()-y)*(h*Q.getY()-y) <= dtSz*dtSz) {
			newQ = true; newP = false; newR = false; newS = false;
		} else if 
		((w*R.getX()-x)*(w*R.getX()-x) + (h*R.getY()-y)*(h*R.getY()-y) <= dtSz*dtSz) {
			newR = true; newP = false; newQ = false; newS = false;
		} else if 
		((w*S.getX()-x)*(w*S.getX()-x) + (h*S.getY()-y)*(h*S.getY()-y) <= dtSz*dtSz) {
			newS = true; newP = false; newQ = false; newR = false; 
		} else {
			newP = false; newQ = false; newR = false; newS = false;
		}
		
		return true;
	}
	public boolean mouseDrag(Event e, int x, int y) {
		if 
		(newP) { P = new Point2D.Double((double)x/w,(double)y/h); 
		} else if
		(newQ) { Q = new Point2D.Double((double)x/w,(double)y/h); 
		} else if
		(newR) { R = new Point2D.Double((double)x/w,(double)y/h); 
		} else if
		(newS) { S = new Point2D.Double((double)x/w,(double)y/h); 
		}
		damage = true;
		return true;
	}
}