Convert Colored Images to Black And white in java

Hi,

Sometime you want to convert colored images to black and white.

Here i am giving you the simple method to do so.

Just see below.

//example for coverting colored image to black and white

import java.awt.image.*;

import javax.imageio.ImageIO;

import java.io.*;

import java.awt.*;

class BlackAndWhite

{

          public static void main(String asr[])

          {

                   try

                   {

                             //colored image path

                             BufferedImage image = ImageIO.read(new  

                                                File("D:\\MyProgram\\output.jpg"));

                             //getting width and height of image

                             double image_width = image.getWidth();

                             double image_height = image.getHeight();

                             BufferedImage bimg = null;

                             BufferedImage img = image;

                             //drawing a new image      

                             bimg = new BufferedImage((int)image_width, (int)image_height,

                                                                    BufferedImage.TYPE_BYTE_GRAY);

                             Graphics2D gg = bimg.createGraphics();

                             gg.drawImage(img, 0, 0, img.getWidth(null), img.getHeight(null), null);

                             //saving black and white image onto drive

                             String temp = "blackAndwhite.jpeg";

                             File fi = new File("D:\\My Program\\" + temp);

                             ImageIO.write(bimg, "jpg", fi);

                   }

                   catch (Exception e)

                   {

                             System.out.println(e);

                   }

          }

}

Dashed line drawing in java graphics.

Hello Friends,

 While working in my project i was searching how to draw a dashed line

in Graphics not in Graphics2D.

So i get this code and it is superb for drawing dash lines or rectangulars.

Just pass the line points and assign your dash length and space length.

See the below function........

////pass the line point x1,y1 and point 2 as x2 and y2

public void drawDashedLine(Graphics g, int x1, int y1, int x2,

                                                   int y2, double dash_length, double space_length)

{

          ///if both the points are same

          if ((x1 == x2) && (y1 == y2))

          {

                   g.drawLine(x1, y1, x2, y2);

                   return;

          }

          ///calculating line length

          double linelength = Math.sqrt((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1));

          double yincrement = (y2 - y1) / (linelength / (dash_length + space_length));

          double xincdashspace = (x2 - x1) / (linelength / (dash_length + space_length));

          double yincdashspace = (y2 - y1) / (linelength / (dash_length + space_length));

          double xincdash = (x2 - x1) / (linelength / (dash_length));

          double yincdash = (y2 - y1) / (linelength / (dash_length));

          int counter = 0;

          for (double i = 0; i < linelength - dash_length; i += dash_length + space_length)

          {

                   g.drawLine((int)(x1 + xincdashspace * counter),

                               (int)(y1 + yincdashspace * counter),

                               (int)(x1 + xincdashspace * counter + xincdash),

                                (int)(y1 + yincdashspace * counter + yincdash));

                   counter++;

          }

          if ((dashlength + spacelength) * counter <= linelength)

                   g.drawLine((int)(x1 + xincdashspace * counter),

                               (int)(y1 + yincdashspace * counter), x2, y2);

}

=============================================

Converting Image to BufferedImage in JAVA

Hi,

While working on some project i was bound in some situation.....

1. For opening image i have to use java.awt.Image class.
   
2. For saving drawn image to jpg i have to use ImageIo class.
3. So for passing ImageIO.write() method i need image object to bufferedImage object.

It is not only one situation when you need this, Sometime when reading

image java.awt.Image class is very useful for opening images from

particular path.

So their are number of tricks to do so.

I am posting here my favorite way of conversion.

Just go through it.

First i loaded image in Image object via Toolkit class.

Then i created a blank BufferedImage object of same dimension.

Then i just draw Image object into BufferedImage object.

Now your BufferedImage object consist the same image.

For full source code follow the link:-

/*

* Program for Converting Image Object to BufferedImage Object

* Copyright 2009 @ yuvadeveloper

* Code By:- Prashant Chandrakar

*

*/

import java.awt.*;

import java.awt.image.*;

class Convert

{

public static void main(String as[])

{

////opening image in Image Object

Image img = Toolkit.getDefaultToolkit().getImage("test.jpeg");

////taking dimension of image

int width = img.getWidth(null);

int height = img.getHeight(null);

////creating a bufferedImage object of same dimension as image

BufferedImage bimg = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);

////taking graphics object from BufferedImage

Graphics2D gg = bimg.createGraphics();

////drawing Image objects image into graphics of buffered image object

gg.drawImage(img, 0, 0, img.getWidth(null), img.getHeight(null), null);

///disposing graphics.

gg.dispose();

}

}

Highlight a selected portion of image in JAVA

Hi,

Here i am crerating a small application which just highlight a

area over image.

I am highlight a rectangular area.You can change as you required.

I am setting a color(255,255,0) for highlight.

You can change it according to your requrement.

Also if you want to change beta value of highlight area then change

the value of transparancy variable.

See the below screenshot where i am highlighted in yellow shed with

transparency value 80.

For full source code follow this link:-

/*

* Program for Highlighting a particular portion of image in any color

* Copyright 2009 @ yuvadeveloper

* Code By:- Prashant Chandrakar

*

*/

import java.awt.*;

import java.awt.image.*;

import java.io.*;

import javax.imageio.*;

class HighlightImage

{

public static void main(String a[])

{

try

{

////pass image file path open for drawing

BufferedImage image = ImageIO.read(new File("1.jpg"));

////taking graphics from image

Graphics g = image.getGraphics();

////just change the transparency value for changing beta values of image

int transparency = 50;

/////drawing string on graphics of opened image

g.drawString("We are highlighting a selected portion of image", 10, 10);

Color color = new Color(255, 255, 0, 255 * transparency / 100);

g.setColor(color);

g.fillRect(30, 30, 100, 100);

////saving image by name output.jpg

ImageIO.write(image, "jpg", new File("output.jpg"));

}

catch (Exception e)

{

System.out.println(e);

}

}

}

ScreenShot:-

Slide Show in java

Hi,

I am posting here a slide show demo in java.

Just change the path of folder containing images.

It is same as xp slide demo.You can just navigate all images by

next and previous button.

You have to just set the path containing lots of images in folder.

For the source code follow the link below

/*

* Program for implementing a Slide show in java

* Copyright 2009 @ yuvadeveloper

* Code By:- Prashant Chandrakar

*/

import javax.swing.*;

import java.awt.*;

import java.awt.image.*;

import java.io.*;

import javax.swing.*;

import java.awt.event.*;

class JSlideShow extends JFrame implements ActionListener

{

JLabel image;

File [] files;

int imageNo;

public JSlideShow()

{

super("SliderDemo by prashant chandrakar");

///for setting folder path containing images

setImageArray();

if(files.length > 0)

image = new JLabel(new ImageIcon(files[0].toString()));

////buttons for navigating images

JButton pre = new JButton("Prev");

pre.setActionCommand("pre");

pre.addActionListener(this);

JButton next = new JButton("Next");

next.setActionCommand("next");

next.addActionListener(this);

JPanel jp = new JPanel();

jp.add(pre);

jp.add(next);

this.setLayout(new BorderLayout());

this.getContentPane().add("North", image);

this.getContentPane().add("Center", jp);

this.setSize(1024, 768);

this.setVisible(true);

this.addWindowListener(new WindowAdapter()

{

public void windowClosing(WindowListener we)

{

System.exit(0);

}

});

}

public void setImageArray()

{

////just change the folder path containing images

File path = new File("d:/nondicom/images/");

files = path.listFiles();

}

public void setImage(int number)

{

image.setIcon(new ImageIcon(files[number].toString()));

}

public void actionPerformed(ActionEvent e)

{

if (e.getActionCommand().equals("pre"))

{

if (imageNo == 0)

{

imageNo = files.length-1;

}

else

{

imageNo--;

}

setImage(imageNo);

}

else if (e.getActionCommand().equals("next"))

{

if (imageNo == files.length-1)

{

imageNo = 0;

}

else

{

imageNo++;

}

setImage(imageNo);

}

}

public static void main(String a[])

{

new JSlideShow();

}

}

Drawing String on image

Hi,

Suppose you want to edit any image and want to write some text permanently

on image.

Here i posting code for do so.

It opens a image name test.jpg and write a text and then save on same place with name "output.jpg".

You just change the name of files as you required.

For source code see below

/*

* Program for drawing string or text over a image and save with that

* Copyright 2009 @ yuvadeveloper

* Code By:- Prashant Chandrakar

*

*/

import java.awt.*;

import java.awt.image.*;

import java.io.*;

import javax.imageio.*;

class DrawString

{

public static void main(String a[])

{

try

{

////pass image file path open for drawing

BufferedImage image = ImageIO.read(new File("test.JPEG"));

////taking graphics from image

Graphics g = image.getGraphics();

/////drawing string on graphics of opened image

g.drawString("I am a string drawn on image pixel", 10, image.getHeight() - 10);

////saving image by name output.jpg

ImageIO.write(image, "jpg", new File("output.jpg"));

}

catch (Exception e)

{

System.out.println(e);

}

}

}