Expert opinion

[alphasil]

Hi

i need to start a project (canvas) with some functions:

Must have several different shapes (triangle, rectangle, lines, elipses, etc).

1 - Do i need to create one class for each one?

2- Must have a list of all of them, do i use hashmap or table??

3 - Each object can move or change colors, i need to create a method for that, but do i have to create a heritage class?

I have started with just two classes, the main (canvas) and other one (objects)

import javax.swing.*;
import java.awt.*;
import java.awt.geom.*;

/**
 * Definição de Objetos.
 * 
 * @gmc 
 * @0.1
 */
public class Objetos
{
    private JFrame frame;
    private JanelaPane g;
    private Graphics2D graphic;
    private Color backgroundColor;
    private Image canvasImage;
    
    public Objetos(String titulo)
     {
        this(titulo, 300, 300, Color.white);        
    }
    
     public Objetos(String titulo, int largura, int altura)
    {
        this(titulo, largura, altura, Color.white);
    }
    
     public Objetos(String titulo, int largura, int altura, Color bgColor)
    {
        frame = new JFrame();
        g = new JanelaPane();
        frame.setContentPane(g);
        frame.setTitle(titulo);
        g.setPreferredSize(new Dimension(largura, altura));
        backgroundColor = bgColor;
        frame.pack();
    }
    
    public void setVisible(Boolean visble)
    {
        frame.setVisible(true);
    }
    
    protected void draw(Shape shape)
    {
        graphic.draw(shape);
        g.repaint();
        
    }
    
    protected void fill(Shape shape)
    {
        graphic.draw(shape);
        g.repaint();
        
    }
    
    protected void apagar(Shape shape)
    {
        Color original = graphic.getColor();
        graphic.setColor(backgroundColor);
        graphic.fill(shape);
        graphic.setColor(original);
        g.repaint();
    }
    
    //Definições dos objetos existentes
    
    public void linhas(int x, int y, int altura, int largura)
    {
        //fill(new Line(x, y, altura, largura));
    }
    
    public void drawLine(int x, int y, int altura, int largura)
    {
        graphic.drawLine(x,y,altura,largura);
        g.repaint();
    }
    
    
    
    //Jframe
    public class JanelaPane extends JPanel
    {
        public void paint(Graphics g)
        {
            g.drawImage(canvasImage, 0, 0, null);
        }
    }
    
}

Can i continue like this?

Thanks

[DarrylBurke]

Please go through the Forum Rules, particularly the third paragraph. Also go through Guide For New Members and BB Code List - Java Programming Forum and edit your post accordingly (to change the subject line, click 'Go Advanced').

db

[alphasil]

Ok

Sorry, now it is ok ?

import javax.swing.*;
import java.awt.*;
import java.awt.geom.*;

/**
 * Definição de Objetos.
 * 
 * @gmc 
 * @0.1
 */
public class Objetos
{
    private JFrame frame;
    private JanelaPane g;
    private Graphics2D graphic;
    private Color backgroundColor;
    private Image canvasImage;
    
    public Objetos(String titulo)
     {
        this(titulo, 300, 300, Color.white);        
    }
    
     public Objetos(String titulo, int largura, int altura)
    {
        this(titulo, largura, altura, Color.white);
    }
    
     public Objetos(String titulo, int largura, int altura, Color bgColor)
    {
        frame = new JFrame();
        g = new JanelaPane();
        frame.setContentPane(g);
        frame.setTitle(titulo);
        g.setPreferredSize(new Dimension(largura, altura));
        backgroundColor = bgColor;
        frame.pack();
    }
    
    public void setVisible(Boolean visble)
    {
        frame.setVisible(true);
    }
    
    protected void draw(Shape shape)
    {
        graphic.draw(shape);
        g.repaint();
        
    }
    
    protected void fill(Shape shape)
    {
        graphic.draw(shape);
        g.repaint();
        
    }
    
    protected void apagar(Shape shape)
    {
        Color original = graphic.getColor();
        graphic.setColor(backgroundColor);
        graphic.fill(shape);
        graphic.setColor(original);
        g.repaint();
    }
    
    //Definições dos objetos existentes
    
    public void linhas(int x, int y, int altura, int largura)
    {
        //fill(new Line(x, y, altura, largura));
    }
    
    public void drawLine(int x, int y, int altura, int largura)
    {
        graphic.drawLine(x,y,altura,largura);
        g.repaint();
    }
    
    
    
    //Jframe
    public class JanelaPane extends JPanel
    {
        public void paint(Graphics g)
        {
            g.drawImage(canvasImage, 0, 0, null);
        }
    }
    
}

Any help please?

[quad64bit]

I don't see your question. What is it again?

[alphasil]

Sorry, i forgot

So, i must make a Canvas with some functions, the first one (adding lines) to the canvas doesn't work.

My main class

import java.awt.Color;
/**
 * Janela principal de funcionamento do programa.
 * 
 * @gmc
 * @0.1 
 */

public class JanelaPrincipal   
{
    private Objetos jan;

    public JanelaPrincipal()
    {
        jan = new Objetos("Trabalho GMC", 600, 500);        
        jan.setVisible(true);
        
    }
    
    public void Desenhar()
    {
       jan.setVisible(true);
       jan.setFundo(Color.blue);
     
    }
 
}

my canvas class

import javax.swing.*;
import java.awt.*;
import java.awt.geom.*;

/**
 * Definição de Objetos.
 * 
 * @gmc 
 * @0.1
 */
public class Objetos
{
    private JFrame frame;
    private JanelaPane g;
    private Graphics2D graphic;
    private Color backgroundColor;
    private Image canvasImage;
    
    public Objetos(String titulo)
     {
        this(titulo, 300, 300, Color.white);        
    }
    
     public Objetos(String titulo, int largura, int altura)
    {
        this(titulo, largura, altura, Color.white);
    }
    
     public Objetos(String titulo, int largura, int altura, Color bgColor)
    {
        frame = new JFrame();
        g = new JanelaPane();
        frame.setContentPane(g);
        frame.setTitle(titulo);
        g.setPreferredSize(new Dimension(largura, altura));
        backgroundColor = bgColor;
        frame.pack();
    }
    
      public void setVisible(boolean visible)
    {
        if(graphic == null) {
            // first time: instantiate the offscreen image and fill it with
            // the background color
            Dimension size = g.getSize();
            canvasImage = g.createImage(size.width, size.height);
            graphic = (Graphics2D)canvasImage.getGraphics();
            graphic.setColor(backgroundColor);
            graphic.fillRect(0, 0, size.width, size.height);
            graphic.setColor(Color.black);
        }
        frame.setVisible(true);
    }

    /**
     * Fornece informacao sobre a visibilidade do Canvas
     * @return  true se o Canvas esta visivel, false caso nao esteja
     */
    public boolean isVisible()
    {
        return frame.isVisible();
    }
    
    
    //Definição de cores e de fundos
    
    public void setFundo(Color nova)
    {
       graphic.setColor(nova);
        
    }
    
    public Color getFundo()
    {
        return graphic.getColor();
    }
    
    public void setCorFundo(Color nova)
    {
        backgroundColor = nova;
        graphic.setBackground(nova);
    }
    
    public Color getCorFundo()
    {
        return backgroundColor;
    }
    
    
    //Fim
    private class JanelaPane extends JPanel
    {
        public void paint(Graphics g)
        {
            linhas obj = new linhas();
            obj.paint(g);
            
        }
    }
        
}

My line class

import java.awt.*;
/**
 * Write a description of class linhas here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class linhas extends Canvas
{
    private String nome;
    private Color cores;
    private int altura;
    private int largura;
    private int posicaoX;
    private int posicaoY;
    /**
     * Constructor for objects of class linhas
     */
    public void linhas(String nome,Color cores,int altura, int largura, int posicaoX, int posicaoY)
    {
        this.nome =nome;
        this.cores=cores;
        this.altura=altura;
        this.largura=largura;
        this.posicaoX=posicaoX;
        this.posicaoY=posicaoY;
    }
    
    public void paint(Graphics g)
        {
            g.drawLine(10,10,10,10);
            g.setColor(Color.blue);
        }
}

I can't get my line in the canvas...

[doWhile]

Some recommendations

• Avoid mixing AWT and Swing - Swing is newer - I'd recommend using a JPanel and not Canvas (AWT).
• I would recommend going through some basic tutorials for how to paint using AWT or Swing ( for instance Trail: 2D Graphics (The Java™ Tutorials) ). For instance don't call getGraphics() on a component unless you know what you are doing.
• I would recommend posting an SSCCE - there is tons of code unrelated to your question and you are asking unpaid volunteers to wade through it all.

[alphasil]

Thanks DoWhile

The main problem is the assignment must have canvas.

Then, a lot of differents shapes with some functions

regards