How to create Image from 8-bit grayscal pixel matrix

Question

Hi,
I am trying to display image from fingerprintscanner.
To communicate with the scanner I use JNI
I've wrote java code which get the image from C++ as a byte[].
To display image I use as sample code from forum tring to display the image.
http://forum.java.sun.com/thread.jspa?forumID=20&threadID=628129
import java.awt.*;
import java.awt.color.*;
import java.awt.image.*;
import java.io.*;
import java.util.*;
import javax.imageio.*;
import javax.swing.*;
public class Example {
public static void main(String[] args) throws IOException {
final int H = 400;
final int W = 600;
byte[] pixels = createPixels(W*H);
BufferedImage image = toImage(pixels, W, H);
display(image);
ImageIO.write(image, "jpeg", new File("static.jpeg"));
public static void _main(String[] args) throws IOException {
BufferedImage m = new BufferedImage(1, 1, BufferedImage.TYPE_BYTE_GRAY);
WritableRaster r = m.getRaster();
System.out.println(r.getClass());
static byte[] createPixels(int size){
byte[] pixels = new byte[size];
Random r = new Random();
r.nextBytes(pixels);
return pixels;
static BufferedImage toImage(byte[] pixels, int w, int h) {
DataBuffer db = new DataBufferByte(pixels, w*h);
WritableRaster raster = Raster.createInterleavedRaster(db,
w, h, w, 1, new int[]{0}, null);
ColorSpace cs = ColorSpace.getInstance(ColorSpace.CS_GRAY);
ColorModel cm = new ComponentColorModel(cs, false, false,
Transparency.OPAQUE, DataBuffer.TYPE_BYTE);
return new BufferedImage(cm, raster, false, null);
static void display(BufferedImage image) {
final JFrame f = new JFrame("");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.getContentPane().add(new JLabel(new ImageIcon(image)));
f.pack();
SwingUtilities.invokeLater(new Runnable(){
public void run() {
f.setLocationRelativeTo(null);
f.setVisible(true);
And I see only white pixels on black background.
Here is description of C++ method:
GetImage
Syntax: unsigned char* GetImage(int handle)
Description: This function grabs the image of a fingerprint from the UFIS scanner.
Parameters: Handle of the scanner
Return values: Pointer to 1D-array, which contains the 8-bit grayscale pixel matrix line by line.
here is sample C++ code which works fine to show image in C++
void Show(unsigned char * bitmap, int W, int H, CClientDC & ClientDC)
int i, j;
short color;
for(i = 0; i < H; i++) {
     for(j = 0; j < W; j++) {
     color = (unsigned char)bitmap[j+i*W];
     ClientDC.SetPixel(j,i,RGB(color,color,color));
Will appreciate your help .

Answer 1

Hi Joel,
The database nls parameters are:
select * from nls_database_parameters;
NLS_LANGUAGE AMERICAN
NLS_TERRITORY AMERICA
NLS_CURRENCY $
NLS_ISO_CURRENCY AMERICA
NLS_NUMERIC_CHARACTERS .,
NLS_CHARACTERSET CL8MSWIN1251
NLS_CALENDAR GREGORIAN
NLS_DATE_FORMAT DD-MON-RR
NLS_DATE_LANGUAGE AMERICAN
NLS_SORT BINARY
NLS_TIME_FORMAT HH.MI.SSXFF AM
NLS_TIMESTAMP_FORMAT DD-MON-RR HH.MI.SSXFF AM
NLS_TIME_TZ_FORMAT HH.MI.SSXFF AM TZR
NLS_TIMESTAMP_TZ_FORMAT DD-MON-RR HH.MI.SSXFF AM TZR
NLS_DUAL_CURRENCY $
NLS_COMP BINARY
NLS_LENGTH_SEMANTICS BYTE
NLS_NCHAR_CONV_EXCP FALSE
NLS_NCHAR_CHARACTERSET AL16UTF16
NLS_RDBMS_VERSION 9.2.0.4.0
Part of the email header:
Content-Type: multipart/alternative; boundary="---=1T02D27M75MU981T02D27M75MU98"
-----=1T02D27M75MU981T02D27M75MU98
-----=1T02D27M75MU981T02D27M75MU98
Content-Type: text/plain; charset=us-ascii
-----=1T02D27M75MU981T02D27M75MU98
Content-Type: text/html;
-----=1T02D27M75MU981T02D27M75MU98--
I think that something is wrong in the WWV_FLOW_MAIL package. In order to send 8-bit characters must be used UTL_SMTP.WRITE_ROW_DATA instead of the UTL_SMTP.WRITE_DATA.
Regards,
Roumen