How to create a bmp file from rgb datas stored in a txt file?

Question

I've to create a bmp image from two txt files.The first one is an mxn array:

* * * * * * * *
m n
c11 c21 .. cm1
...
c1n c2n .. cmn
* * * * * * * *

* * * * * * * *
6 5
.7 .7 .6 1.0 1.2 .1
.9 .3 .7 1.1 .7 .2
1 1.1 1.2 1.3 1.7 .6
.5 .6 .5 .4 .9 .1101
2 .1 .1 .1 2.1 1.1
* * * * * * * *

The second txt file is a color scale, like this

* * * * * * * *
min1 max1 r1 g1 b1
min2 max2 r2 g2 b2
...
minx maxx rx gx bx
* * * * * * * *

* * * * * * * *
0 .5 255 128 64
.5 .75 128 255 32
.75 1.25 64 64 225
01.50 5 128 128 0
* * * * * * * *

So I've to read from this two files. I've tried to create an array from the first txt file using StringTokenizer class but I'm lost at all. From the two files I've to create a bmp image. Someone can help me in some way?

Answer 1

Sigh... while I wrote the program down, @jarnbjo explained the same idea. But here you have some code:

import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.util.NavigableMap;
import java.util.TreeMap;

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

public class ImageParser {
    public static void main(String[] args) {
        String dataContent = 
            "6 5\n" + 
            ".7 .7 .6 1.0 1.2 .1\n" + 
            ".9 .3 .7 1.1 .7 .2\n" + 
            "1 1.1 1.2 1.3 1.7 .6\n" + 
            ".5 .6 .5 .4 .9 .1101\n" + 
            "2 .1 .1 .1 2.1 1.1";

        String colorContent = 
            "0 .5 255 128 64\n" + 
            ".5 .75 128 255 32\n" + 
            ".75 1.25 64 64 225\n" + 
            "01.50 5 128 128 0";

        int width = 0;
        int height = 0;
        BufferedImage image = null;

        NavigableMap<Double, Integer> colorMap = new TreeMap<Double, Integer>();
        for (String colorLine : colorContent.split( "\n" )) {
            String[] colorValues = colorLine.split( " " );
            colorMap.put( Double.parseDouble( colorValues[1] ), 
                    Integer.parseInt( colorValues[2] ) << 16 | 
                    Integer.parseInt( colorValues[3] ) << 8 | 
                    Integer.parseInt( colorValues[4] ) );
        }
        boolean headerParsed = false;
        int y = 0;
        for( String dataLine : dataContent.split( "\n" ) ) {
            String[] dataArray = dataLine.split( " " );
            if( !headerParsed ) {
                width = Integer.parseInt( dataArray[ 0 ] );
                height = Integer.parseInt( dataArray[ 1 ] );
                image = new BufferedImage( width, height, BufferedImage.TYPE_INT_RGB );
                headerParsed = true;
            }
            else {
                int x = 0;
                for( String data : dataArray ) {
                    Integer rgbValue = colorMap.higherEntry( Double.parseDouble( data ) ).getValue();
                    image.setRGB( x, y, rgbValue );
                    x++;
                }
                y++;
            }
        }

        JFrame frame = new JFrame();
        frame.getContentPane().add( new Viewer( image, width, height, 20 ) );
        frame.pack();
        frame.setVisible( true );
    }

    static class Viewer extends JPanel {
        Image m_image;
        int m_width;
        int m_height;
        int m_zoom;
        public Viewer( Image image, int width, int height, int zoom ) {
            m_image = image;
            m_width = width;
            m_height = height;
            m_zoom = zoom;
        }

        @Override
        public void paint(Graphics g) {
            g.drawImage( m_image, 0, 0, m_width * m_zoom, m_height * m_zoom, this );
        }
    };
}