How to capture signature using Canvas and save in png format?

**aelynne** · June 2nd, 2012, 12:13 AM

I have done this, but i have problem to save the image? can someone help me?

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JTextField;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
 
 
public class UserInterface 
{
    public static void main(String[] args) 
        {
                JFrame projectFrame = new JFrame();
                projectFrame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
                JPanel projectPanel = new JPanel();
                JPanel btnPanel = new JPanel();
                JButton encode = new JButton("ENCODE");
                JButton decode = new JButton("DECODE");
 
                encode.addActionListener(new ButtonListener());
                decode.addActionListener(new ButtonListener());
 
                projectFrame.setSize(600,500);
                projectFrame.setTitle("ONLINE SIGNATURE STEGANOGRAPHY");  
                projectFrame.setResizable(true);
                projectPanel.setLayout(new FlowLayout());
 
                JLabel stego = new JLabel("ONLINE SIGNATURE STEGANOGRAPHY SYSTEM");
                stego.setFont(new Font("Tahoma", Font.BOLD, 20));
 
                projectFrame.add(projectPanel);
                projectFrame.add(btnPanel, BorderLayout.PAGE_END);
                projectPanel.add(stego);
                btnPanel.add(encode);
                btnPanel.add(decode);
                projectFrame.setVisible(true);
        }
 
        static class ButtonListener implements ActionListener   
 {         
  public void actionPerformed(ActionEvent ae) 
  {
   if(ae.getActionCommand().equals("ENCODE"))
   {
    new encodePane();
   }
   if(ae.getActionCommand().equals("DECODE"))
   {
    new decodePane();
   }
 
  }
 }
}
 
 
        class encodePane
        {
 
           public encodePane() 
            {
  final JFrame encodeFrame = new JFrame();
                Container content = encodeFrame.getContentPane();
                content.setLayout(new BorderLayout());
                JPanel encodePanel = new JPanel();
                JPanel buttonPanel = new JPanel();
 
                final PadDraw drawPad = new PadDraw();
                content.add(drawPad, BorderLayout.CENTER);
 
                JButton cancelBtn = new JButton("CANCEL");
                cancelBtn.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent e) {
                encodeFrame.dispose();
                }
                });
 
                JButton proceedBtn = new JButton("PROCEED");
                proceedBtn.addActionListener(new ActionListener() { 
                public void actionPerformed(ActionEvent e){
                     new encode1Pane();
                     encodeFrame.dispose();
                     }   
                });  
 
                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();
                        }
                });
 
                JLabel Sign = new JLabel("Sign here:", SwingConstants.CENTER);
                Sign.setVerticalAlignment(SwingConstants.TOP);
 
               // proceedBtn.addActionListener(new Button1Listener());
 
                encodeFrame.setTitle("ENCODE SECTION");
                encodeFrame.setLocationRelativeTo(null);   
                encodeFrame.setSize(600,500); 
                encodeFrame.setResizable(true);
                encodePanel.setLayout(new FlowLayout());
 
                encodePanel.add(Sign);
 
                encodeFrame.add(encodePanel, BorderLayout.NORTH);
                encodeFrame.add(buttonPanel, BorderLayout.SOUTH);
 
                buttonPanel.setLayout(new BoxLayout(buttonPanel, BoxLayout.LINE_AXIS));
                buttonPanel.setBorder(BorderFactory.createEmptyBorder(0, 10, 10, 10));
                buttonPanel.add(Box.createHorizontalGlue());
                buttonPanel.add(clearButton);
                buttonPanel.add(Box.createRigidArea(new Dimension(10, 0)));
                buttonPanel.add(cancelBtn);
                buttonPanel.add(Box.createRigidArea(new Dimension(10, 0)));
                buttonPanel.add(proceedBtn);
 
                Sign.setFont(new Font("Serif", Font.ITALIC, 14));
                encodeFrame.setVisible(true);
 }
 
 
        /*static class Button1Listener implements ActionListener 
  {   
   public void actionPerformed(ActionEvent ae)  
   {
    if(ae.getActionCommand().equals("PROCEED"))
    {
                                    new encode1Pane();
                                }
 
                        }
  }*/
       }
 
       class PadDraw extends JComponent{
 
            Image image;
            Graphics2D graphics2D;
            int currentX, currentY, oldX, oldY;
 
            public PadDraw(){
                setDoubleBuffered(false);
                addMouseListener(new MouseAdapter(){
                    public void mousePressed(MouseEvent e){
                        oldX = e.getX();
                        oldY = e.getY();
                    }
                });
            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; 
                }
            });
            }
       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);
       }
 
       public void clear(){
           graphics2D.setPaint(Color.white);
           graphics2D.fillRect(0,0,getSize().width, getSize().height);
           graphics2D.setPaint(Color.black);
           repaint();
 
 
       }
 
}
 
       class encode1Pane
       {
           public encode1Pane()
           {
              final JFrame encode1Frame = new JFrame();
              JPanel Enc = new JPanel();
              JPanel enc = new JPanel();
              JPanel Btn = new JPanel();
              JButton prcd = new JButton ("ENCODE");
              JLabel sec = new JLabel ("Your message");
              final JTextField secText = new JTextField ("");
              secText.setPreferredSize(new Dimension (500, 100));
              JLabel name = new JLabel ("Set the file name");
              final JTextField name2 = new JTextField ();
              name2.setPreferredSize(new Dimension (200, 20));
              JButton cncl = new JButton ("CANCEL");
              cncl.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent e) {
                new encodePane();
                encode1Frame.dispose();
                }
                });
 
 
              encode1Frame.setTitle("ENCODE SECTION");
              encode1Frame.setLocationRelativeTo(null);   
              encode1Frame.setSize(600,500);
              encode1Frame.setResizable(true);
 
              Enc.add(sec);
              Enc.add(secText);
              secText.setBounds(30, 50, 200, 25);
              enc.add(name);
              enc.add(name2);
              name2.setBounds(30, 50, 200, 25);
              encode1Frame.add(Btn, BorderLayout.SOUTH);
              encode1Frame.add(Enc, BorderLayout.NORTH);
              encode1Frame.add(enc, BorderLayout.CENTER);
              encode1Frame.setVisible(true);   
 
              Btn.setLayout(new BoxLayout(Btn, BoxLayout.LINE_AXIS));
              Btn.setBorder(BorderFactory.createEmptyBorder(0, 10, 10, 10));
              Btn.add(Box.createHorizontalGlue());
              Btn.add(cncl);
              Btn.add(Box.createRigidArea(new Dimension(10, 0)));
              Btn.add(prcd);
 
 
              sec.setFont(new Font("Serif", Font.ITALIC, 14));
              name.setFont(new Font("Serif", Font.ITALIC, 14));
              //cncl.addActionListener(new Button2Listener());
              prcd.addActionListener(new Button2Listener());
 
       }
 
           static class Button2Listener implements ActionListener 
  {   
   public void actionPerformed(ActionEvent ae)  
   {
    if(ae.getActionCommand().equals("Proceed"))
    {
      //new encodeOutput();
    }    
   }
                 }
       }
 
 
        class decodePane 
            {
               public decodePane() 
                {
                    JFrame decodeFrame = new JFrame();
                    decodeFrame.add(new UploadImage());
 
                }}

**Norm** · June 2nd, 2012, 08:47 AM

Where are you trying to write the image to a file?

**aelynne** · June 3rd, 2012, 06:58 AM

Originally Posted by Norm

Where are you trying to write the image to a file?

sorry, this is my new code. when i run, it save blank black image. i want to save the drawing on the canvas. please help me.

import javax.swing.*;
 
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.colorchooser.*;
import javax.swing.event.*;
import java.awt.geom.Line2D;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import javax.imageio.ImageIO;
 
 
public class PaintIt extends JFrame implements ActionListener{
 
 
 
public BufferedImage image = new BufferedImage(500, 500, BufferedImage.TYPE_INT_RGB);
//JPanel canvas = new JPanel();
 
    JPanel buttonPanel = new JPanel();
    Point lastPos = null;
    Point startPos = null;
    Point finishPos = null;
    Graphics g;
    JButton save = new JButton("Save");
    JButton cancel = new JButton("Cancel");
    JButton clear = new JButton("Clear");
    JButton proceed = new JButton("Proceed");
    JPanel canvas = new JPanel();
    int changer = 1;
    String path="";
 
    public PaintIt () {
 
 
        setLocation(100,100);
        setSize(600,500);
        setTitle("ENCODE SECTION");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        canvas.setBackground(Color.WHITE);
 
        clear.addActionListener(this);
        clear.setActionCommand("clear");
 
        save.addActionListener(this);
        save.setActionCommand("Save");
 
 
        cancel.addActionListener(this);
        cancel.setActionCommand("Cancel");
 
        proceed.addActionListener(this);
        proceed.setActionCommand("Proceed");
 
        //add buttons here
 
        buttonPanel.setLayout(new BoxLayout(buttonPanel, BoxLayout.LINE_AXIS));
        buttonPanel.setBorder(BorderFactory.createEmptyBorder(0, 10, 10, 10));
        buttonPanel.add(Box.createHorizontalGlue());
        buttonPanel.add(save);
        buttonPanel.add(Box.createRigidArea(new Dimension(10, 0)));
        buttonPanel.add(clear);
        buttonPanel.add(Box.createRigidArea(new Dimension(10, 0)));
        buttonPanel.add(cancel);
        buttonPanel.add(Box.createRigidArea(new Dimension(10, 0)));
        buttonPanel.add(proceed);
 
        //set the look
        getContentPane().add(canvas, BorderLayout.CENTER);
        getContentPane().add(buttonPanel, BorderLayout.SOUTH);
        setVisible(true);
 
        g = canvas.getGraphics();
        g.setColor(Color.BLACK);
 
        canvas.addMouseMotionListener(new MouseMotionListener () {                      
            public void mouseDragged (MouseEvent m) {
                Point p = m.getPoint() ;
                if (changer==1){
                g.drawLine(lastPos.x, lastPos.y, p.x, p.y) ;
                }           
                lastPos = p ;
 
            }   
            public void mouseMoved (MouseEvent m) {}
        });
 
        canvas.addMouseListener(new MouseListener () {
            public void mouseClicked(MouseEvent e) {startPos = e.getPoint();}
            public void mousePressed(MouseEvent e) {lastPos = e.getPoint();}
            public void mouseReleased(MouseEvent e) {
            lastPos = null; 
            finishPos = e.getPoint(); 
            startPos = null;}
            public void mouseEntered(MouseEvent e) {}
            public void mouseExited(MouseEvent e) {}
            });
 
 
    }
 
 
 
    public void actionPerformed(ActionEvent e) {
        if("clear".equals(e.getActionCommand())) {
            repaint();
        }
        if("Save".equals(e.getActionCommand())) {
            captureCanvasImage myCanvas = new captureCanvasImage();
            myCanvas.capture();
        }
        if("Cancel".equals(e.getActionCommand())) {
            dispose();
        }
        if("Proceed".equals(e.getActionCommand())) {
            new encode1Pane();
        }}
 
 
    class captureCanvasImage {
        public void capture(){
 
        Graphics g = image.createGraphics();
        canvas.paint(g);
        int w = canvas.getWidth();
        int h = canvas.getHeight();
        //BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
        //g.dispose();
        try
        {
            BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
            g.dispose();
            ImageIO.write(image, "png", new File("original.png"));
        }
        catch(IOException ioe)
        {
            System.out.println("Panel write help: " + ioe.getMessage());
        }
    }
 
            }
 
 
    /*
    @Override
    public void invalidate() {     
    super.invalidate(); 
 
    this.paint(this.getGraphics()); 
    }
*/
 
    public static void main (String [] args) {
        PaintIt p = new PaintIt();
        p.setVisible(true);
    }
}

**Norm** · June 3rd, 2012, 07:11 AM

The code does not compile because of missing class definitions.

How does the code get what was written on the canvas so it can be written to a file?

**aelynne** · June 3rd, 2012, 07:12 AM

i can compile it. nothing problem

**Norm** · June 3rd, 2012, 07:17 AM

copy the source to a new folder away from the other files and try compiling it.

**aelynne** · June 3rd, 2012, 07:35 AM

try this. i already done that, nothing problem. my problem is how to save the image i draw in the canvas.

 import javax.swing.*;
 
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.colorchooser.*;
import javax.swing.event.*;
import java.awt.geom.Line2D;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import javax.imageio.ImageIO;
 
 
public class PaintIt extends JFrame implements ActionListener{
 
 
 
public BufferedImage image = new BufferedImage(400, 300, BufferedImage.TYPE_INT_RGB);
//JPanel canvas = new JPanel();
 
    JPanel buttonPanel = new JPanel();
    JPanel sign = new JPanel();
    JLabel signlabel = new JLabel("Sign here :");
    Point lastPos = null;
    Point startPos = null;
    Point finishPos = null;
    Graphics g;
    JButton save = new JButton("Save");
    JButton cancel = new JButton("Cancel");
    JButton clear = new JButton("Clear");
    JButton proceed = new JButton("Proceed");
    JPanel canvas = new JPanel();
    int changer = 1;
    String path="";
 
    public PaintIt () {
 
 
        setLocation(100,100);
        setSize(600,500);
        setTitle("ENCODE SECTION");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        canvas.setBackground(Color.WHITE);
 
        clear.addActionListener(this);
        clear.setActionCommand("clear");
 
        save.addActionListener(this);
        save.setActionCommand("Save");
 
 
        cancel.addActionListener(this);
        cancel.setActionCommand("Cancel");
 
        proceed.addActionListener(this);
        proceed.setActionCommand("Proceed");
 
        //add buttons here
 
        buttonPanel.setLayout(new BoxLayout(buttonPanel, BoxLayout.LINE_AXIS));
        buttonPanel.setBorder(BorderFactory.createEmptyBorder(0, 10, 10, 10));
        buttonPanel.add(Box.createHorizontalGlue());
        buttonPanel.add(save);
        buttonPanel.add(Box.createRigidArea(new Dimension(10, 0)));
        buttonPanel.add(clear);
        buttonPanel.add(Box.createRigidArea(new Dimension(10, 0)));
        buttonPanel.add(cancel);
        buttonPanel.add(Box.createRigidArea(new Dimension(10, 0)));
        buttonPanel.add(proceed);
 
        sign.add(signlabel);
        signlabel.setFont(new Font("Serif", Font.ITALIC, 14));
 
        //set the look
        getContentPane().add(canvas, BorderLayout.CENTER);
        getContentPane().add(buttonPanel, BorderLayout.SOUTH);
        getContentPane().add(sign, BorderLayout.PAGE_START);
        setVisible(true);
 
        g = canvas.getGraphics();
        g.setColor(Color.BLACK);
 
        canvas.addMouseMotionListener(new MouseMotionListener () {                      
            public void mouseDragged (MouseEvent m) {
                Point p = m.getPoint() ;
                if (changer==1){
                g.drawLine(lastPos.x, lastPos.y, p.x, p.y) ;
                }           
                lastPos = p ;
 
            }   
            public void mouseMoved (MouseEvent m) {}
        });
 
        canvas.addMouseListener(new MouseListener () {
            public void mouseClicked(MouseEvent e) {startPos = e.getPoint();}
            public void mousePressed(MouseEvent e) {lastPos = e.getPoint();}
            public void mouseReleased(MouseEvent e) {
            lastPos = null; 
            finishPos = e.getPoint(); 
            startPos = null;}
            public void mouseEntered(MouseEvent e) {}
            public void mouseExited(MouseEvent e) {}
            });
 
 
    }
 
 
 
    public void actionPerformed(ActionEvent e) {
        if("clear".equals(e.getActionCommand())) {
            repaint();
        }
        if("Save".equals(e.getActionCommand())) {
            captureCanvasImage myCanvas = new captureCanvasImage();
            myCanvas.capture();
        }
        if("Cancel".equals(e.getActionCommand())) {
            dispose();
        }
        if("Proceed".equals(e.getActionCommand())) {
            //new encode1Pane();
        }}
 
 
    class captureCanvasImage {
        public void capture(){
 
        Graphics g = image.createGraphics();
        canvas.paint(g);
        int w = image.getWidth();
        int h = image.getHeight();
        //BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
        //g.dispose();
        try
        {
            BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
            g.dispose();
            ImageIO.write(image, "png", new File("original.png"));
        }
        catch(IOException ioe)
        {
            System.out.println("Panel write help: " + ioe.getMessage());
        }
    }
 
            }
 
 
    /*
    @Override
    public void invalidate() {     
    super.invalidate(); 
 
    this.paint(this.getGraphics()); 
    }
*/
 
    public static void main (String [] args) {
        PaintIt p = new PaintIt();
        p.setVisible(true);
    }
}

**Norm** · June 3rd, 2012, 07:44 AM

how to save the image i draw in the canvas.

You need to save the points used to draw the lines in some container like an arraylist so you can you use them when you want to save what was drawn on the jpanel.

Your method of drawing the image of lines is wrong. You need to override the component's paintComponent method and draw the lines there using what you have saved in the arraylist.
If you move the frame with the image past the side of the monitor, the drawn lines are erased. Or if you minimize and restore the window the image is gone.

**aelynne** · June 3rd, 2012, 07:52 AM

i dont get it, can you give some example?

**Norm** · June 3rd, 2012, 07:56 AM

There are lots of code examples here on the forum. Do a search for paintComponent for example.

Also look at the tutorial:
http://docs.oracle.com/javase/tutori...ing/index.html

**aelynne** · June 3rd, 2012, 08:02 AM

take a look at this, i have paint component. but how I can save the image?

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JTextField;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import javax.imageio.ImageIO;
 
 
public class UserInterface 
{
    public static void main(String[] args) 
        {
                JFrame projectFrame = new JFrame();
                projectFrame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
                JPanel projectPanel = new JPanel();
                JPanel btnPanel = new JPanel();
                JButton encode = new JButton("ENCODE");
                JButton decode = new JButton("DECODE");
 
                encode.addActionListener(new ButtonListener());
                decode.addActionListener(new ButtonListener());
 
                projectFrame.setSize(600,500);
                projectFrame.setTitle("ONLINE SIGNATURE STEGANOGRAPHY");  
                projectFrame.setResizable(true);
                projectPanel.setLayout(new FlowLayout());
 
                JLabel stego = new JLabel("ONLINE SIGNATURE STEGANOGRAPHY SYSTEM");
                stego.setFont(new Font("Tahoma", Font.BOLD, 20));
 
                projectFrame.add(projectPanel);
                projectFrame.add(btnPanel, BorderLayout.PAGE_END);
                projectPanel.add(stego);
                btnPanel.add(encode);
                btnPanel.add(decode);
                projectFrame.setVisible(true);
        }
 
        static class ButtonListener implements ActionListener   
 {         
  public void actionPerformed(ActionEvent ae) 
  {
   if(ae.getActionCommand().equals("ENCODE"))
   {
    new encodePane();
   }
   if(ae.getActionCommand().equals("DECODE"))
   {
    new decodePane();
   }
 
  }
 }
}
 
 
        class encodePane
        {
 
           public encodePane() 
            {
                final JFrame encodeFrame = new JFrame();
                Container content = encodeFrame.getContentPane();
                content.setLayout(new BorderLayout());
                JPanel encodePanel = new JPanel();
                JPanel buttonPanel = new JPanel();
 
                final PadDraw drawPad = new PadDraw();
                content.add(drawPad, BorderLayout.CENTER);
 
                JButton cancelBtn = new JButton("CANCEL");
                cancelBtn.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent e) {
                encodeFrame.dispose();
                }
                });
 
                JButton proceedBtn = new JButton("PROCEED");
                proceedBtn.addActionListener(new ActionListener() { 
                public void actionPerformed(ActionEvent e){
                     new encode1Pane();
                     encodeFrame.dispose();
                     }   
                });  
 
                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();
                        }
                });
 
                JLabel Sign = new JLabel("Sign here:", SwingConstants.CENTER);
                Sign.setVerticalAlignment(SwingConstants.TOP);
 
               // proceedBtn.addActionListener(new Button1Listener());
 
                encodeFrame.setTitle("ENCODE SECTION");
                encodeFrame.setLocationRelativeTo(null);   
                encodeFrame.setSize(600,500); 
                encodeFrame.setResizable(true);
                encodePanel.setLayout(new FlowLayout());
 
                encodePanel.add(Sign);
 
                encodeFrame.add(encodePanel, BorderLayout.NORTH);
                encodeFrame.add(buttonPanel, BorderLayout.SOUTH);
 
                buttonPanel.setLayout(new BoxLayout(buttonPanel, BoxLayout.LINE_AXIS));
                buttonPanel.setBorder(BorderFactory.createEmptyBorder(0, 10, 10, 10));
                buttonPanel.add(Box.createHorizontalGlue());
                buttonPanel.add(clearButton);
                buttonPanel.add(Box.createRigidArea(new Dimension(10, 0)));
                buttonPanel.add(cancelBtn);
                buttonPanel.add(Box.createRigidArea(new Dimension(10, 0)));
                buttonPanel.add(proceedBtn);
 
                Sign.setFont(new Font("Serif", Font.ITALIC, 14));
                encodeFrame.setVisible(true);
 
           }}
 
       class PadDraw extends JComponent{
 
            Image image;
            Graphics2D graphics2D;
            int currentX, currentY, oldX, oldY;
 
            public PadDraw(){
                setDoubleBuffered(false);
                addMouseListener(new MouseAdapter(){
                    public void mousePressed(MouseEvent e){
                        oldX = e.getX();
                        oldY = e.getY();
                    }
                });
            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; 
                }
            });
            }
       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);
       }
 
       public void clear(){
           graphics2D.setPaint(Color.white);
           graphics2D.fillRect(0,0,getSize().width, getSize().height);
           graphics2D.setPaint(Color.black);
           repaint();
 
       }
 
}
 
       class encode1Pane
       {
           public encode1Pane()
           {
              final JFrame encode1Frame = new JFrame();
              JPanel Enc = new JPanel();
              JPanel enc = new JPanel();
              JPanel Btn = new JPanel();
              JButton prcd = new JButton ("ENCODE");
              JLabel sec = new JLabel ("Your message");
              final JTextField secText = new JTextField ("");
              secText.setPreferredSize(new Dimension (500, 100));
              JLabel name = new JLabel ("Set the file name");
              final JTextField name2 = new JTextField ();
              name2.setPreferredSize(new Dimension (200, 20));
              JButton cncl = new JButton ("CANCEL");
              cncl.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent e) {
                new encodePane();
                encode1Frame.dispose();
                }
                });
 
 
              encode1Frame.setTitle("ENCODE SECTION");
              encode1Frame.setLocationRelativeTo(null);   
              encode1Frame.setSize(600,500);
              encode1Frame.setResizable(true);
 
              Enc.add(sec);
              Enc.add(secText);
              secText.setBounds(30, 50, 200, 25);
              enc.add(name);
              enc.add(name2);
              name2.setBounds(30, 50, 200, 25);
              encode1Frame.add(Btn, BorderLayout.SOUTH);
              encode1Frame.add(Enc, BorderLayout.NORTH);
              encode1Frame.add(enc, BorderLayout.CENTER);
              encode1Frame.setVisible(true);   
 
              Btn.setLayout(new BoxLayout(Btn, BoxLayout.LINE_AXIS));
              Btn.setBorder(BorderFactory.createEmptyBorder(0, 10, 10, 10));
              Btn.add(Box.createHorizontalGlue());
              Btn.add(cncl);
              Btn.add(Box.createRigidArea(new Dimension(10, 0)));
              Btn.add(prcd);
 
 
              sec.setFont(new Font("Serif", Font.ITALIC, 14));
              name.setFont(new Font("Serif", Font.ITALIC, 14));
              //cncl.addActionListener(new Button2Listener());
              prcd.addActionListener(new Button2Listener());
 
       }
 
           static class Button2Listener implements ActionListener 
  {   
   public void actionPerformed(ActionEvent ae)  
   {
    if(ae.getActionCommand().equals("Proceed"))
    {
      //new encodeOutput();
    }    
   }
                 }
       }
 
 
        class decodePane 
            {
               public decodePane() 
                {
                    JFrame decodeFrame = new JFrame();
                    decodeFrame.add(new UploadImage());
 
                }}

**Norm** · June 3rd, 2012, 08:08 AM

Can make a small simple program that compiles, executes and shows the problem? The posted code has endcode and decode classes and other stuff that is not part of the problem.

**aelynne** · June 3rd, 2012, 08:16 AM

this is the code example same as i do. how to add save function to it?

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
 
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
 
public class Main {
  public static void main(String[] args) {
    JFrame frame = new JFrame();
    final DrawPad drawPad = new DrawPad();
    frame.add(drawPad, BorderLayout.CENTER);
    JButton clearButton = new JButton("Clear");
    clearButton.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        drawPad.clear();
      }
    });
    frame.add(clearButton, BorderLayout.SOUTH);
    frame.setSize(280, 300);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
  }
 
}
class DrawPad extends JComponent {
  Image image;
  Graphics2D graphics2D;
  int currentX, currentY, oldX, oldY;
  public DrawPad() {
    setDoubleBuffered(false);
    addMouseListener(new MouseAdapter() {
      public void mousePressed(MouseEvent e) {
        oldX = e.getX();
        oldY = e.getY();
      }
    });
    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;
      }
    });
  }
 
  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);
  }
 
  public void clear() {
    graphics2D.setPaint(Color.white);
    graphics2D.fillRect(0, 0, getSize().width, getSize().height);
    graphics2D.setPaint(Color.black);
    repaint();
  }
}

**Norm** · June 3rd, 2012, 08:25 AM

Write the image in the image variable to a file.

**aelynne** · June 3rd, 2012, 08:35 AM

is it in here

 if (image == null

?

**Norm** · June 3rd, 2012, 08:38 AM

Is that the variable named: image? That is where the image has been drawn.

**aelynne** · June 3rd, 2012, 08:51 AM

i dont get it. i'm new to java. can u give example? or help me add in my code?

**Norm** · June 3rd, 2012, 08:55 AM

The first code you posted has code in it to write an image to a file. Copy the code from that program.

**aelynne** · June 3rd, 2012, 09:05 AM

like this? but i it have error

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
 
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
 
public class Main {
  public static void main(String[] args) {
    JFrame frame = new JFrame();
    final DrawPad drawPad = new DrawPad();
    frame.add(drawPad, BorderLayout.CENTER);
    JButton clearButton = new JButton("Clear");
    clearButton.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        drawPad.clear();
      }
    });
    JButton save = new JButton("Save");
    save.addActionListener(new ActionListener(){
    public void actionPerformed(ActionEvent e) {
                if("Save".equals(e.getActionCommand())) {
            captureCanvasImage myCanvas = new captureCanvasImage();
            myCanvas.capture();
                }}});
 
    frame.add(clearButton, BorderLayout.SOUTH);
    frame.setSize(280, 300);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
  }
 
}
class DrawPad extends JComponent {
  Image image;
  Graphics2D graphics2D;
  int currentX, currentY, oldX, oldY;
  public DrawPad() {
    setDoubleBuffered(false);
    addMouseListener(new MouseAdapter() {
      public void mousePressed(MouseEvent e) {
        oldX = e.getX();
        oldY = e.getY();
      }
    });
    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;
      }
    });
  }
 
  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);
  }
 
  public void clear() {
    graphics2D.setPaint(Color.white);
    graphics2D.fillRect(0, 0, getSize().width, getSize().height);
    graphics2D.setPaint(Color.black);
    repaint();
  }
}
 
class captureCanvasImage {
        public void capture(){
        Graphics g = image.createGraphics();
        canvas.paint(g);
        //myCanvas = new Canvas( mBitmap );
        int w = image.getWidth();
        int h = image.getHeight();
 
        //BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
        //g.dispose();
        try
        {
            BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
            g.dispose();
            ImageIO.write(image, "png", new File("original.png"));
 
        }
        catch(IOException ioe)
        {
            System.out.println("Panel write help: " + ioe.getMessage());
        }
    }
 
            }

**Norm** · June 3rd, 2012, 09:22 AM

it have error

When you get errors, you need to copy and paste here the full text of the error message.

**aelynne** · June 3rd, 2012, 09:27 AM

my error is in here. at the canvas, image n so on. getWidth, getHeight. what should i replace to that?

 public void capture(){
        Graphics g = image.createGraphics();
        canvas.paint(g);
        //myCanvas = new Canvas( mBitmap );
        int w = image.getWidth();
        int h = image.getHeight();
 
        //BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
        //g.dispose();
        try
        {
            BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
            g.dispose();
            ImageIO.write(image, "png", new File("original.png"));
 
        }
        catch(IOException ioe)
        {
            System.out.println("Panel write help: " + ioe.getMessage());
        }
    }

**aelynne** · June 3rd, 2012, 09:28 AM

my error is in here. at the canvas, image n so on. getWidth, getHeight. what should i replace to that?

 public void capture(){
        Graphics g = image.createGraphics();
        canvas.paint(g);
        //myCanvas = new Canvas( mBitmap );
        int w = image.getWidth();
        int h = image.getHeight();
 
        //BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
        //g.dispose();
        try
        {
            BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
            g.dispose();
            ImageIO.write(image, "png", new File("original.png"));
 
        }
        catch(IOException ioe)
        {
            System.out.println("Panel write help: " + ioe.getMessage());
        }
    }

**Norm** · June 3rd, 2012, 09:31 AM

Please post the full text of the error message.

What is the method you posted supposed to do? The image already exists in the code in post#13

**aelynne** · June 3rd, 2012, 09:39 AM

this the error,paint.jpg

**Norm** · June 3rd, 2012, 09:54 AM

Please copy and paste here the full text of the error message. Images are no good because you can not copy text from them to do a find for what is referred to in the error message.

To copy the contents of the command prompt window:
Click on Icon in upper left corner
Select Edit
Select 'Select All' - The selection will show
Click in upper left again
Select Edit and click 'Copy'

Paste here.

A screen shot of your IDE does not help me.

Thread: How to capture signature using Canvas and save in png format?

LinkBack

Thread Tools

Display

How to capture signature using Canvas and save in png format?

Related threads:

Re: How to capture signature using Canvas and save in png format?

Re: How to capture signature using Canvas and save in png format?

Re: How to capture signature using Canvas and save in png format?

Re: How to capture signature using Canvas and save in png format?

Re: How to capture signature using Canvas and save in png format?

Re: How to capture signature using Canvas and save in png format?

Re: How to capture signature using Canvas and save in png format?

Re: How to capture signature using Canvas and save in png format?

Re: How to capture signature using Canvas and save in png format?

Re: How to capture signature using Canvas and save in png format?

Re: How to capture signature using Canvas and save in png format?

Re: How to capture signature using Canvas and save in png format?

Re: How to capture signature using Canvas and save in png format?

Re: How to capture signature using Canvas and save in png format?

Re: How to capture signature using Canvas and save in png format?

Re: How to capture signature using Canvas and save in png format?

Re: How to capture signature using Canvas and save in png format?

Re: How to capture signature using Canvas and save in png format?

Re: How to capture signature using Canvas and save in png format?

Re: How to capture signature using Canvas and save in png format?

Re: How to capture signature using Canvas and save in png format?

Re: How to capture signature using Canvas and save in png format?

Re: How to capture signature using Canvas and save in png format?

Re: How to capture signature using Canvas and save in png format?

Similar Threads

How to save Image into a package by JButton save?

Need help to save Canvas content to a file

Why does not forum allow signature?

Audio capture (TargetDataLine) latency

Call with a different signature