mainframeelipsa.java

Java project demonstrating how to obtain the intersection of two circles.

package adim.swing;

import java.awt.Canvas;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

import java.awt.event.MouseEvent;

import java.awt.event.MouseMotionListener;
import java.awt.event.MouseWheelEvent;
import java.awt.event.MouseWheelListener;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;
import java.awt.image.BufferedImage;

import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;




public class MainFrameElipsa extends JFrame implements WindowListener
{

	private static final long serialVersionUID = 1L;
	private JPanel mainPanel;
	private CanvasElipse theCanvas;
	
	
	MainFrameElipsa()
	{
		mainPanel = new JPanel();
		mainPanel.setLayout(null);
		mainPanel.setPreferredSize(new Dimension(640, 480));
		
		setContentPane(mainPanel);
		addWindowListener(this);
		
		
		setDefaultCloseOperation(DO_NOTHING_ON_CLOSE);
		
		theCanvas = new CanvasElipse();
		theCanvas.setSize(new Dimension(640, 480));
		mainPanel.add(theCanvas);
		
		
		setTitle("Elipse");
		setLocation(200, 200);
		pack();
		setVisible(true);	
	}
	
	public static void main(String[] args) 
	{
	 new MainFrameElipsa();
	}

	@Override
	public void windowActivated(WindowEvent e) {
		// TODO Auto-generated method stub
		
	}

	@Override
	public void windowClosed(WindowEvent e) {
		// TODO Auto-generated method stub
		
	}

	@Override
	public void windowClosing(WindowEvent e) {
		// TODO Auto-generated method stub
		dispose();
		System.exit(0);		
	}

	@Override
	public void windowDeactivated(WindowEvent e) {
		// TODO Auto-generated method stub
		
	}

	@Override
	public void windowDeiconified(WindowEvent e) {
		// TODO Auto-generated method stub
		
	}

	@Override
	public void windowIconified(WindowEvent e) {
		// TODO Auto-generated method stub
		
	}

	@Override
	public void windowOpened(WindowEvent e) {
		// TODO Auto-generated method stub
		
	}
}


class CanvasElipse extends Canvas implements MouseMotionListener, Runnable, MouseWheelListener
{

    boolean amDeCalculatCeva;
	BufferedImage imgOffScreenBuffer;
	Graphics theGraphics;
	Thread trdRefreshScreen;
	//Thread trdCalculIntersectie; 
	int fps = 60;
	
	
	private double centruIntersectieX, centruIntersectieY;
	
	private boolean primaData ;
	private int x1, y1, r1, x2, y2, r2;
	
	CanvasElipse()
	{
	 //JOptionPane.showInputDialog("constructor");	
		
	addMouseMotionListener(this);
	addMouseWheelListener(this);
			
	amDeCalculatCeva = false;
	
	 x1 = 420;
	 y1 = 213;
	 r1 = 100;
		
	 x2 = 420;
	 y2 = 213;
	 r2 = 100;
	 
	 imgOffScreenBuffer = new BufferedImage(640, 480, BufferedImage.TYPE_INT_ARGB);
	 theGraphics = imgOffScreenBuffer.getGraphics();
	 
	/*
	 x1 = 360;
	 y1 = 190;
	 r1 = 60;
		
	 x2 = 420;
	 y2 = 213;
	 r2 = 100;
	*/
	 
	trdRefreshScreen = new Thread(this);
	trdRefreshScreen.start();
	
	//trdCalculIntersectie = new Thread(this);
	//trdCalculIntersectie.start();
		
	 primaData = true;
	}
	 
	public void paint(Graphics g) 
	{
	 g.drawImage(imgOffScreenBuffer, 0, 0, 640, 480, this);
	}
	
	
	public void update(Graphics g)
	{
		paint(g);
	}
	


private void Linie(double x1, double y1, double x2, double y2)
{
  theGraphics.setColor(Color.white);
  theGraphics.drawLine((int)x1, (int)y1, (int)x2, (int)y2);
 
}
	   
private void FillIntersectieCercuriLiniiOrizontale(int x1, int y1, int r1, int x2, int y2, int r2)
{
	if( ( (x1 - x2) * (x1 - x2)  + (y1 - y2) * (y1 - y2) ) >= (r1 + r2) * (r1 + r2) ) return;	

	// se intersecteaza, determin yStart (y cel mai mic, a.i e pe unul dintre cercuri)
	// apoi, pentru y de la yStart in jos, verific daca dreapta 

	int yStart;
	if(y1 - r1 > y2 - r2)
		yStart = y1 - r1;
	else 
		yStart = y2 - r2;
		
	// faza 0   parcurg liniile incepand de la cel mai de sus punct al cercului de sus, pana cand obtin solutii comune 
	//          (adica, aflu primul punct de intersectie dintre cercuri)
	// faza 1   completez liniie, si testez daca am ajuns la cealalta intersectie dintre cercuri; daca am ajuns, stop
	
	
	//Linie(0, yStart, getWidth(), yStart);
	
	
	
	for(int y = yStart; true; y++)
	{
	 // scot solutiile s1, s2, s3 si s4, ce reprezinta intersectia dreptei f(x) = y   
     // cu cercurile c1, si c2, de ecuatie
	 // (x - x1) ^ 2 + (y - y1) ^ 2 = r1 ^ 2 si 
	 // (x - x2) ^ 2 + (y - y2) ^ 2 = r2 ^ 2
		
	int deltaCerc1 = (r1 * r1) -  ((y-y1) * (y-y1)) ;
	int deltaCerc2 = (r2 * r2) -  ((y-y2) * (y-y2)) ;
	
	//double epsilon = 0.01;
	
	if(deltaCerc1 < 0 || deltaCerc2 < 0 ) break;
	
	// aflu solutiile s1, s2, s3, s4
	
	int solutii[] = new int[4];
	solutii[0] = x1 - (int)Math.sqrt(deltaCerc1);
	solutii[1] = x1 + (int)Math.sqrt(deltaCerc1);
	solutii[2] = x2 - (int)Math.sqrt(deltaCerc2);
	solutii[3] = x2 + (int)Math.sqrt(deltaCerc2);
	
	// aleg solutiile potrivite, in sp1, sp2
	int sp1=0, sp2=0;	
	int solutieMinima = Math.min( Math.min( Math.min(solutii[0], solutii[1]), solutii[2]), solutii[3] );
	int solutieMaxima = Math.max( Math.max( Math.max(solutii[0], solutii[1]), solutii[2]), solutii[3] );
	
	
	boolean amGasitMinim = false;
	boolean amGasitMaxim = false;
	
	int solCount = 0;
	for(int i=0; i<4; i++) 
		{
		 if( amGasitMinim == false && solutii[i] == solutieMinima )
		     {
			  amGasitMinim = true;
			  continue;
		     }
		 
		 if( amGasitMaxim == false && solutii[i] == solutieMaxima )
		     {
			  amGasitMaxim = true;
			  continue;
		     }
			 
		 if( amGasitMinim == true && solutii[i] == solutieMinima  )
		 {
			 if(solCount==0) 
			   {
				solCount++;
				sp1 = solutii[i];
			   }
			 else
			 {
				 sp2 = solutii[i];
				 break;
			 }
		       	 
		 }
		 
		 if( amGasitMaxim == true && solutii[i] == solutieMaxima  )
		 {
			 if(solCount==0) 
			   {
				solCount++;
				sp1 = solutii[i];
			   }
			 else
			 {
				 sp2 = solutii[i];
				 break;
			 }
		       	 
		 }
		 
	
		 if(solutii[i] != solutieMinima && solutii[i] != solutieMaxima)
		 {
		    if(solCount == 0)
		    {
		     solCount++;
		     sp1 = solutii[i];
		    }
		    else