Java simple rgb to hex converter

Complete source code below is a small java program that convert rgb value to hex value. Now i will share with you how to get hex value from rgb value. Before i go far, let we see a description about hex value structure.


VALUE THAT YOU GET AFTER DIVIDE OR MULTIPLY

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15
HEX VALUE0123456789ABCDEF

TABLE A

For example :
FFFFFF is a hex value for white and it's rgb value is 255 255 255.First FF is value for red, second FF is value for green and last FF is for blue.So it mean, first 255 in rgb is equal to first FF in hex value.Now i will show you, how to get FF from 255.For this tutorial i show you only for red part. You can try other last two part for green and blue. Now take 255 and devide it with 16. You should get 15.9375. Take value before floating point. In this case we get 15. Look at TABLE A at above. 15 is equal to F. Now you get first F.For second F, take value after floating point and multiply it with 16. In this case you should multiply 0.9375 with 16. It's result is equal to 15 and it also hold F.Now you get hex value for red part.I hope you can understand what i tried to say.

********************************************************************
COMPLETE SOURCE CODE FOR : RGBtoHEX.java
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import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;

import java.awt.GridLayout;
import java.awt.Color;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class RGBtoHEX implements ActionListener
{
JTextField r=new JTextField(10);
JTextField g=new JTextField(10);
JTextField b=new JTextField(10);

JLabel rLabel=new JLabel("R",JLabel.CENTER);
JLabel gLabel=new JLabel("G",JLabel.CENTER);
JLabel bLabel=new JLabel("B",JLabel.CENTER);

JPanel panelTextField=new JPanel();
JPanel panelLabel=new JPanel();

JButton button=new JButton("Calculate Now !");

JTextField result=new JTextField(30);

public RGBtoHEX()
{
button.addActionListener(this);

r.setHorizontalAlignment(JTextField.CENTER);
g.setHorizontalAlignment(JTextField.CENTER);
b.setHorizontalAlignment(JTextField.CENTER);

result.setHorizontalAlignment(JTextField.CENTER);
result.setBackground(new Color(255,255,255));
result.setEditable(false);

panelLabel.setLayout(new GridLayout(1,3));
panelLabel.add(rLabel);
panelLabel.add(gLabel);
panelLabel.add(bLabel);

panelTextField.setLayout(new GridLayout(1,3));
panelTextField.add(r);
panelTextField.add(g);
panelTextField.add(b);

JFrame myMainWindow=new JFrame("RGB to HEX");
myMainWindow.getContentPane().setLayout(new GridLayout(4,1));
myMainWindow.getContentPane().add(panelLabel);
myMainWindow.getContentPane().add(panelTextField);
myMainWindow.getContentPane().add(button);
myMainWindow.getContentPane().add(result);

myMainWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
myMainWindow.setSize(300,130);
myMainWindow.setLocationRelativeTo(null);
myMainWindow.setVisible(true);
}

public void actionPerformed(ActionEvent event)
{
try
{
String hexValue="#";
r.setEditable(false);
g.setEditable(false);
b.setEditable(false);

double red=Double.parseDouble(r.getText());
double green=Double.parseDouble(g.getText());
double blue=Double.parseDouble(b.getText());

for(int i=1;i<=3;i++)
{
double temp=0;

if(i==1)
{
 temp=red;
}
else if(i==2)
{
 temp=green;
}
else if(i==3)
{
 temp=blue;
}

double devideResult=temp/16;

String stringDevideResult=Double.toString(devideResult);

int pointIndexInString=stringDevideResult.indexOf(".");

String firstValue=stringDevideResult.substring(0,pointIndexInString);

double multiplySixteen=(devideResult-(Double.parseDouble(firstValue)))*16;

String stringMultiplySixteen=Double.toString(multiplySixteen);

pointIndexInString=stringMultiplySixteen.indexOf(".");

String secondValue=stringMultiplySixteen.substring(0,pointIndexInString);

if(firstValue.equalsIgnoreCase("10"))
{
 firstValue="A";
}
if(firstValue.equalsIgnoreCase("11"))
{
 firstValue="B";
}
if(firstValue.equalsIgnoreCase("12"))
{
 firstValue="C";
}
if(firstValue.equalsIgnoreCase("13"))
{
 firstValue="D";
}
if(firstValue.equalsIgnoreCase("14"))
{
 firstValue="E";
}
if(firstValue.equalsIgnoreCase("15"))
{
 firstValue="F";
}
if(secondValue.equalsIgnoreCase("10"))
{
 secondValue="A";
}
if(secondValue.equalsIgnoreCase("11"))
{
 secondValue="B";
}
if(secondValue.equalsIgnoreCase("12"))
{
 secondValue="C";
}
if(secondValue.equalsIgnoreCase("13"))
{
 secondValue="D";
}
if(secondValue.equalsIgnoreCase("14"))
{
 secondValue="E";
}
if(secondValue.equalsIgnoreCase("15"))
{
 secondValue="F";
}

hexValue=hexValue+firstValue+secondValue;
}


result.setText(hexValue);
r.setEditable(true);
g.setEditable(true);
b.setEditable(true);
}
catch(Exception exception)
{
JOptionPane.showMessageDialog(null,"Program error and it will terminate","ERROR",JOptionPane.ERROR_MESSAGE);
System.exit(0);
}
}

public static void main(String[]args)
{
RGBtoHEX converter=new RGBtoHEX();
}
}


********************************************************************
JUST COMPILE AND EXECUTE IT
********************************************************************

Java simple image magnifier tooltip


Sometime when we play with images...i mean here a lot of images, like we let user choose an image from 500 images in a JFrame and all images show at the same time without any scrollbar, it can give user a little problem if the image too small. So, how can user make a good choice. This give me some idea to built my own image tooltip. This is a simple tooltip. It will enlarge image when someone hover mouse cursor on it.Image below is a result from program below.


Before you compile and execute it, you should download all images below. After that place them at same location with this java source file.

Love_Music_by_jovincent.jpg

Leafs_1_by_NerghaL.jpg

Hancock-1611.jpg

matrix.jpg

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COMPLETE SOURCE CODE FOR : ImageToolTip.java
********************************************************************


import javax.swing.JPanel;
import javax.swing.ImageIcon;
import javax.swing.JFrame;

import java.awt.GridLayout;
import java.awt.Graphics;

import java.awt.event.MouseListener;
import java.awt.event.MouseEvent;

public class ImageToolTip
{
public static void main(String[]args)
{
 PanelImage imageA=new PanelImage("matrix.jpg");

 PanelImage imageB=new PanelImage("Hancock-1611.jpg");

 PanelImage imageC=new PanelImage("Leafs_1_by_NerghaL.jpg");

 PanelImage imageD=new PanelImage("Love_Music_by_jovincent.jpg");

 JFrame myMainWindow=new JFrame("Image Tool Tip");
 myMainWindow.setResizable(false);
 myMainWindow.getContentPane().setLayout(new GridLayout(2,2));
 myMainWindow.getContentPane().add(imageA);
 myMainWindow.getContentPane().add(imageB);
 myMainWindow.getContentPane().add(imageC);
 myMainWindow.getContentPane().add(imageD);

 myMainWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 myMainWindow.setSize(100,100);
 myMainWindow.setLocationRelativeTo(null);
 myMainWindow.setVisible(true);
}
}

class PanelImage extends JPanel implements MouseListener
{
ImageIcon temp;
ImageMagnifier im;

public PanelImage(String a)
{
 addMouseListener(this);
 temp=new ImageIcon(a);
}

public void paint(Graphics g)
{
 super.paint(g);
 g.drawImage(temp.getImage(),0,0,getSize().width,getSize().height,this);
}

public void mouseClicked(MouseEvent event)
{
}

public void mouseEntered(MouseEvent event)
{
 im=new ImageMagnifier(temp,getSize().width,getSize().height,event.getXOnScreen(),event.getYOnScreen());
}

public void mouseExited(MouseEvent event)
{
 im.dispose();
}

public void mousePressed(MouseEvent event)
{
}

public void mouseReleased(MouseEvent event)
{
}
}

class ImageMagnifier extends JFrame
{
ImageIcon temp;

public ImageMagnifier(ImageIcon imageFile,int width,int height,int x,int y)
{
 setUndecorated(true);
 temp=imageFile;
 setLocation(x,y);
 setSize(width*9,height*9);
 setVisible(true);
}

public void paint(Graphics g)
{
 super.paint(g);
 g.drawImage(temp.getImage(),0,0,getSize().width,getSize().height,this);
}
}


********************************************************************
JUST COMPILE AND EXECUTE IT
********************************************************************