Okay, all you Java programmers out there!  Here’s my first tutorial!  The last time I checked, there wasn’t a Java paint program out here yet, so hopefully I’m the first.  This tutorial will cover pretty much all of the code involved, so I guess this counts as a beginner tut.  So, in this program that we’ll be making(if you do it right), you’ll be able to draw on a blank white canvas, change the colors of your brush, and clear it!  Enough chat, let’s do it!



Things needed before-code:
Okay, so some things that you’ll need to do before the code is make an 16×16 GIF for each of the colors that we’ll have, so you’ll need a blue, green, magenta, black, and red GIF (create seperate GIFs.  It’s not that hard.  Just go to Microsoft Paint[if you’re using a Microsoft OS], make a 16×16 image and fill the canvas with that color).  Or, you could use mine, which are attached. =D

Remember to save the GIFs as the names of the GIFs in the code, or just change the code to fit your file names.



Something else to do(I guess you don’t have to, but I like to keep things organised), is to create a Paint folder and store all your code and images in it.

Now that you’ve done all that, we can get to the actual code =]



/*

 * Code by NomNom /*

 */

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

public class paint{

       
public static void main(String[] args){

               
Icon iconB = new ImageIcon("blue.gif");

               
//the blue image icon

               
Icon iconM = new ImageIcon("magenta.gif");

               
//magenta image icon

               
Icon iconR = new ImageIcon("red.gif");

               
//red image icon

               
Icon iconBl = new ImageIcon("black.gif");

               
//black image icon

               
Icon iconG = new ImageIcon("green.gif");

               
//finally the green image icon

               
//These will be the images for our colors.

               

               
JFrame frame = new JFrame("Paint It");

               
//Creates a frame with a title of "Paint it"

               

               
Container content = frame.getContentPane();

               
//Creates a new container

                content
.setLayout(new BorderLayout());

               
//sets the layout

               

               
final PadDraw drawPad = new PadDraw();

               
//creates a new padDraw, which is pretty much the paint program

               

                content
.add(drawPad, BorderLayout.CENTER);

               
//sets the padDraw in the center

               

      &nb sp;        
JPanel panel = new JPanel();

               
//creates a JPanel

                panel
.setPreferredSize(new Dimension(32, 68));

                panel
.setMinimumSize(new Dimension(32, 68));

                panel
.setMaximumSize(new Dimension(32, 68));

               
//This sets the size of the panel

               

               
JButton clearButton = new JButton("Clear");

               
//creates the clear button and sets the text as "Clear"

                clearButton
.addActionListener(new ActionListener(){

                       
public void actionPerformed(ActionEvent e){

                                drawPad
.clear();

                       
}

               
});

               
//this is the clear button, which clears the screen.  This pretty

               
//much attaches an action listener to the button and when the

               
//button is pressed it calls the clear() method

               

               
JButton redButton = new JButton(iconR);

               
//creates the red button and sets the icon we created for red

                redButton
.addActionListener(new ActionListener(){

                       
public void actionPerformed(ActionEvent e){

                                drawPad
.red();

                       
}


               
});

               
//when pressed it will call the red() method.  So on and so on =]

               

               
JButton blackButton = new JButton(iconBl);

               
//same thing except this is the black button

                blackButton
.addActionListener(new ActionListener(){

                       
public void actionPerformed(ActionEvent e){

                                drawPad
.black();

                       
}

               
});

               

               
JButton magentaButton = new JButton(iconM);

               
//magenta button

                magentaButton
.addActionListener(new ActionListener(){

                       
public void actionPerformed(ActionEvent e){

                                drawPad
.magenta();

                       
}

               
});

               

               
JButton blueButton = new JButton(iconB);

               
//blue button

                blueButton
.addActionListener(new ActionListener(){

                       
public void actionPerformed(ActionEvent e){

                                drawPad
.blue();

                       
}

               
});

               

               
JButton greenButton = new JButton(iconG);

               
//green button

                greenButton
.addActionListener(new ActionListener(){

                       
public void actionPerformed(ActionEvent e){

                                drawPad
.green();

                       
}

               
});

                blackButton
.setPreferredSize(new Dimension(16, 16));

                magentaButton
.setPreferredSize(new Dimension(16, 16));

                redButton
.setPreferredSize(new Dimension(16, 16));

                blueButton
.setPreferredSize(new Dimension(16, 16));

                greenButton
.setPreferredSize(new Dimension(16,16));

               
//sets the sizes of the buttons

               

                panel
.add(greenButton);

                panel
.add(blueButton);

                panel
.add(magentaButton);

                panel
.add(blackButton);

                panel
.add(redButton);

                panel
.add(clearButton);

               
//adds the buttons to the panel

               

                content
.add(panel, BorderLayout.WEST);

               
//sets the panel to the left

               

                frame
.setSize(300, 300);

               
//sets the size of the frame

                frame
.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

               
//makes it so you can close

                frame
.setVisible(true);

               
//makes it so you can see it

       
}
}

class PadDraw extends JComponent{

       
Image image;

       
//this is gonna be your image that you draw on

       
Graphics2D graphics2D;

       
//this is what we'll be using to draw on

       
int currentX, currentY, oldX, oldY;

       
//these are gonna hold our mouse coordinates


       
//Now for the constructors

       
public PadDraw(){

                setDoubleBuffered
(false);

                addMouseListener
(new MouseAdapter(){

                       
public void mousePressed(MouseEvent e){

                                oldX
= e.getX();

                                oldY
= e.getY();

                       
}

               
});

               
//if the mouse is pressed it sets the oldX & oldY

               
//coordinates as the mouses x & y coordinates

                addMouseMotionListener
(new MouseMotionAdapter(){

                       
public void mouseDragged(MouseEvent e){

                                currentX
= e.getX();

                                currentY
= e.getY();

                               
if(graphics2D != null)

                                graphics2D
.drawLine(oldX, oldY, currentX, currentY);

                                repaint
();

                                oldX
= currentX;

                                oldY
= currentY;

                       
}


               
});

               
//while the mouse is dragged it sets currentX & currentY as the mouses x and y

               
//then it draws a line at the coordinates

               
//it repaints it and sets oldX and oldY as currentX and currentY

       
}


       
public void paintComponent(Graphics g){

               
if(image == null){

                        image
= createImage(getSize().width, getSize().height);

                        graphics2D
= (Graphics2D)image.getGraphics();

                        graphics2D
.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

                        clear
();


               
}

                g
.drawImage(image, 0, 0, null);

       
}

       
//this is the painting bit

       
//if it has nothing on it then

       
//it creates an image the size of the window

       
//sets the value of Graphics as the image

       
//sets the rendering

       
//runs the clear() method

       
//then it draws the image



       
public void clear(){

                graphics2D
.setPaint(Color.white);

                graphics2D
.fillRect(0, 0, getSize().width, getSize().height);

                graphics2D
.setPaint(Color.black);

                repaint
();

       
}

       
//this is the clear

       
//it sets the colors as white

       
//then it fills the window with white

       
//thin it sets the color back to black

       
public void red(){

                graphics2D
.setPaint(Color.red);

                repaint
();

       
}

       
//this is the red paint

       
public void black(){

                graphics 2D
.setPaint(Color.black);

                repaint
();

       
}

       
//black paint

       
public void magenta(){

                graphics2D
.setPaint(Color.magenta);

                repaint
();

       
}

       
//magenta paint

       
public void blue(){

                graphics2D
.setPaint(Color.blue);

                repaint
();

       
}

       
//blue paint

       
public void green(){

                graphics2D
.setPaint(Color.green);

                repaint
();

       
}

       
//green paint
}

//good job, you've made your paint program =]


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