Grafica in Java - figuri geometrice


    Java dispune de numeroase clase cum ar fi clasa "Graphics", care permit realizarea de grafica in applet-uri.

  • Figuri geometrice

        Cele mai importante elemente grafice care pot fi utilizate in cadrul mediului de dezvoltare JAVA sunt elemente grafice.
        Urmatoarea aplicatie plaseaza mai multe figuri geometrice pe un applet.

        In cazul ca nu se lanseaza aplicatia de sus, pe calculatorul d-voastra trebuie instalat pachetul JDC versiunea JDK6 sau mai recenta.

        Cum se plaseaza elemente grafice intr-un applet ? 
    package Grafice;


import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Rectangle;
import java.awt.GridBagLayout;
import javax.swing.JPanel;
import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JLabel;
import java.awt.Graphics;

public class linii_v1_0 extends JApplet {

	private static final long serialVersionUID = 1L;
	private JPanel c_panel_1 = null; // panel_1 cu controale plasate
	private JPanel panel_1 = null; // panoul 1
	private JLabel etich_1 = null; // eticheta 1
	private JButton but_1 = null; // butonul 1
	private Graphics grf=null;


	/**
	 * Aceasta metoda initializeaza: this
	 * 
	 * @returneaza  void
	 */
	public void init() {
		this.setSize(350, 300);
		this.setContentPane(init_panel_1());
	}

	/**
	 * Constructorul implicit pentru "linii_v2"
	 */
	public linii_v1_0() {
		super();
	}
	private void deseneaza()
	{
		if(grf==null){
			grf=panel_1.getGraphics();
		}
		grf.clearRect(0, 0, getSize().width, getSize().height);
		grf.setColor(Color.BLUE);
		grf.drawRect(10, 10, 220, 190);// dreptungi cu coordonatele:(x,y,w,h)
		grf.setColor(Color.RED);
		grf.drawLine(20, 20, 290, 180);// linie cu coordonatele:(x,y,x2,y2)
		grf.setColor(Color.green);
		grf.drawLine( 90,170, 185, 18);// linie cu coordonatele:(x,y,x2,y2)
		grf.setColor(Color.magenta);
		grf.drawOval(40, 30, 240, 110);// elipsa cu coordonatele:(x,y,w,h)
	}
	
	
	/**
	 * 	/**
	 * Aceasta metoda creaza panelul: "but_1"	
	 * Returneaza but_1 de tipul:	javax.swing.JButton
	 */
	
	
	private JButton creaza_but_1() {
		if (but_1 == null) {
			but_1 = new JButton();
			but_1.setBounds(new Rectangle(120, 260, 70, 30));
			but_1.setText("Start");
			
			but_1.addActionListener(new java.awt.event.ActionListener() {
				public void actionPerformed(java.awt.event.ActionEvent e) {
					deseneaza();
					
				}
			});
		}
		return but_1;
	}

	/**
	 * This method initializes jPanel	
	 * 	
	 * @return javax.swing.JPanel	
	 */
	private JPanel creaza_panel_1() {
		if (panel_1 == null) {
			panel_1 = new JPanel();
			panel_1.setLayout(new GridBagLayout());
			panel_1.setBounds(new Rectangle(20, 30, 300, 220));
			// se forteaza culoarea fundalului 
			//this.setBackground(c_panel_1.getBackground());
		}
		return panel_1;
	}

	/**
	 * Aceasta metoda initializeaza panel_1 plasand controalele dorite 
	 * Returneaza c_panel_1 de tipul: javax.swing.JPanel 
	 */
	
	
	private JPanel init_panel_1() {
		if (c_panel_1 == null) {
			etich_1 = new JLabel();
			etich_1.setBounds(new Rectangle(10, 10, 200, 10));
			etich_1.setText("Apasati butonul Start");
			c_panel_1 = new JPanel();
			c_panel_1.setLayout(null);
			c_panel_1.add(creaza_but_1(), null);
			c_panel_1.add(etich_1, null);
			c_panel_1.add(creaza_panel_1(), null);
			c_panel_1.setLayout(new BorderLayout());
		}
		return c_panel_1;
	}
}


        Schimband functia deseneaza, cu: 

    	    public void deseneaza() {
			if(grf==null){
				grf=panel_1.getGraphics();
			}
			//grf.clearRect(0, 0, getSize().width, getSize().height);
	    	grf.setColor(Color.MAGENTA);
	        for (int x = 0 ; x < getSize().width/2 ; x+=10) {    
		    grf.drawOval(150-x/2, 100-x/2, x, x);
	        }
	    }

        Obtinem graficul functiei sinus modulat in amplitudine cu alt sinus:


        Pentru a nu mai fi nevoiti sa apasam butonul "Start" vom introduce un timer care va declansa procedura de desenare. 

    package Grafice;


import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Rectangle;
import java.awt.GridBagLayout;
import javax.swing.JPanel;
import javax.swing.JApplet;
import javax.swing.Timer;

import java.awt.Graphics;

public class linii_v1 extends JApplet {

	private static final long serialVersionUID = 1L;
	private JPanel c_panel_1 = null; 	// panel_1 cu controale plasate
	private JPanel panel_1 = null; 		// panoul 1
    private int delay=500;				// temporizare
    private Timer timer_1=null;			// timer 1
	private Graphics grf=null;


	/**
	 * Aceasta metoda initializeaza: this
	 * 
	 * @returneaza  void
	 */
	public void init() {
		this.setSize(350, 300);
		this.setContentPane(init_panel_1());
	}

	/**
	 * Constructorul implicit pentru "linii_v2"
	 */
	public linii_v1() {
		super();
	}
	private void deseneaza()
	{
		if(grf==null){
			grf=panel_1.getGraphics();
		}
		grf.clearRect(0, 0, getSize().width, getSize().height);
		grf.setColor(Color.BLUE);
		grf.drawRect(10, 10, 220, 190);// dreptungi cu coordonatele:(x,y,w,h)
		grf.setColor(Color.RED);
		grf.drawLine(20, 20, 290, 180);// linie cu coordonatele:(x,y,x2,y2)
		grf.setColor(Color.green);
		grf.drawLine( 90,170, 185, 18);// linie cu coordonatele:(x,y,x2,y2)
		grf.setColor(Color.magenta);
		grf.drawOval(40, 30, 240, 110);// elipsa cu coordonatele:(x,y,w,h)
		//timer_1.stop();
	}
	
	
	/**
	 * 	/**
	 * Aceasta metoda creaza panelul: "but_1"	
	 * Returneaza but_1 de tipul:	javax.swing.JButton
	 */
	
	
	private void creaza_timer_1() {

		if (timer_1 == null) {
				timer_1 = new Timer(delay, null);
				//timer_1.setInitialDelay(delay *1); // Temporizare initiala
				timer_1.setCoalesce(true);
				timer_1.addActionListener(new java.awt.event.ActionListener() {
					public void actionPerformed(java.awt.event.ActionEvent e) {
						deseneaza();
					}
				});					
}
}		

	/**
	 * This method initializes jPanel	
	 * 	
	 * @return javax.swing.JPanel	
	 */
	private JPanel creaza_panel_1() {
		if (panel_1 == null) {
			panel_1 = new JPanel();
			panel_1.setLayout(new GridBagLayout());
			panel_1.setBounds(new Rectangle(20, 30, 300, 220));
			// se forteaza culoarea fundalului 
			//this.setBackground(c_panel_1.getBackground());
		}
		return panel_1;
	}

	/**
	 * Aceasta metoda initializeaza panel_1 plasand controalele dorite 
	 * Returneaza c_panel_1 de tipul: javax.swing.JPanel 
	 */
	
	
	private JPanel init_panel_1() {
		if (c_panel_1 == null) {

			c_panel_1 = new JPanel();
			c_panel_1.setLayout(null);
			c_panel_1.add(creaza_panel_1(), null);
			c_panel_1.setLayout(new BorderLayout());
			creaza_timer_1();
			timer_1.start();
		}
		return c_panel_1;
	}
}


        Obtinem: