import java.awt.Image;
import java.awt.Toolkit;
import java.awt.image.MemoryImageSource;
import java.io.FileInputStream;
import java.io.IOException;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
//
//really just a collection of methods to read a BMP file
//
public class BMPLoader
{
// build an int from a byte array - convert little to big endian
public static int constructInt(byte[] in, int offset) {
int ret = ((int) in[offset + 3] & 0xff);
ret = (ret << 8) | ((int) in[offset + 2] & 0xff);
ret = (ret << 8) | ((int) in[offset + 1] & 0xff);
ret = (ret << 8) | ((int) in[offset + 0] & 0xff);
return (ret);
}
// build an int from a byte array - convert little to big endian
// set high order bytes to 0xfff
public static int constructInt3(byte[] in, int offset) {
int ret = 0xff;
ret = (ret << 8) | ((int) in[offset + 2] & 0xff);
ret = (ret << 8) | ((int) in[offset + 1] & 0xff);
ret = (ret << 8) | ((int) in[offset + 0] & 0xff);
return (ret);
}
// build an int from a byte array - convert little to big endian
public static long constructLong(byte[] in, int offset) {
long ret = ((long) in[offset + 7] & 0xff);
ret |= (ret << 8) | ((long) in[offset + 6] & 0xff);
ret |= (ret << 8) | ((long) in[offset + 5] & 0xff);
ret |= (ret << 8) | ((long) in[offset + 4] & 0xff);
ret |= (ret << 8) | ((long) in[offset + 3] & 0xff);
ret |= (ret << 8) | ((long) in[offset + 2] & 0xff);
ret |= (ret << 8) | ((long) in[offset + 1] & 0xff);
ret |= (ret << 8) | ((long) in[offset + 0] & 0xff);
return (ret);
}
// build an double from a byte array - convert little to big endian
public static double constructDouble(byte[] in, int offset) {
long ret = constructLong(in, offset);
return (Double.longBitsToDouble(ret));
}
// build an short from a byte array - convert little to big endian
public static short constructShort(byte[] in, int offset) {
short ret = (short) ((short) in[offset + 1] & 0xff);
ret = (short) ((ret << 8) | (short) ((short) in[offset + 0] & 0xff));
return (ret);
}
// internal class representing a bitmap header structure
// with code to read it from a file
static class BitmapHeader {
public int nsize;
public int nbisize;
public int nwidth;
public int nheight;
public int nplanes;
public int nbitcount;
public int ncompression;
public int nsizeimage;
public int nxpm;
public int nypm;
public int nclrused;
public int nclrimp;
// read in the bitmap header
public void read(FileInputStream fs) throws IOException
{
final int bflen = 14; // 14 byte BITMAPFILEHEADER
byte bf[] = new byte[bflen];
fs.read(bf, 0, bflen);
final int bilen = 40; // 40-byte BITMAPINFOHEADER
byte bi[] = new byte[bilen];
fs.read(bi, 0, bilen);
// Interperet data.
nsize = constructInt(bf, 2);
// System.out.println("File type is :"+(char)bf[0]+(char)bf[1]);
// System.out.println("Size of file is :"+nsize);
nbisize = constructInt(bi, 2);
// System.out.println("Size of bitmapinfoheader is :"+nbisize);
nwidth = constructInt(bi, 4);
// System.out.println("Width is :"+nwidth);
nheight = constructInt(bi, 8);
// System.out.println("Height is :"+nheight);
nplanes = constructShort(bi, 12); //(((int)bi[13]&0xff)<<8) |
// (int)bi[12]&0xff;
// System.out.println("Planes is :"+nplanes);
nbitcount = constructShort(bi, 14); //(((int)bi[15]&0xff)<<8) |
// (int)bi[14]&0xff;
// System.out.println("BitCount is :"+nbitcount);
// Look for non-zero values to indicate compression
ncompression = constructInt(bi, 16);
// System.out.println("Compression is :"+ncompression);
nsizeimage = constructInt(bi, 20);
// System.out.println("SizeImage is :"+nsizeimage);
nxpm = constructInt(bi, 24);
// System.out.println("X-Pixels per meter is :"+nxpm);
nypm = constructInt(bi, 28);
// System.out.println("Y-Pixels per meter is :"+nypm);
nclrused = constructInt(bi, 32);
// System.out.println("Colors used are :"+nclrused);
nclrimp = constructInt(bi, 36);
// System.out.println("Colors important are :"+nclrimp);
}
}
public static Image read(FileInputStream fs)
{
try {
BitmapHeader bh = new BitmapHeader();
bh.read(fs);
if (bh.nbitcount == 24)
return (readMap24(fs, bh));
if (bh.nbitcount == 32)
return (readMap32(fs, bh));
if (bh.nbitcount == 8)
return (readMap8(fs, bh));
fs.close();
} catch (IOException e) {
// System.out.println("Caught exception in loadbitmap!");
}
return (null);
}
/**
*
* readMap24 internal routine to read the bytes in a 24 bit bitmap
*
*
*
* Arguments:
*
* fs - file stream
*
* bh - header struct
*
* Returns:
*
* Image Object, be sure to check for (Image)null !!!!
*
*
*
*/
protected static Image readMap32(FileInputStream fs, BitmapHeader bh)
throws IOException
{
Image image;
// No Palatte data for 24-bit format but scan lines are
// padded out to even 4-byte boundaries.
int xwidth = bh.nsizeimage / bh.nheight;
int ndata[] = new int[bh.nheight * bh.nwidth];
byte brgb[] = new byte[bh.nwidth * 4 * bh.nheight];
fs.read(brgb, 0, bh.nwidth * 4 * bh.nheight);
int nindex = 0;
for (int j = 0; j < bh.nheight; j++)
{
for (int i = 0; i < bh.nwidth; i++)
{
ndata[bh.nwidth * (bh.nheight - j - 1) + i] = constructInt3(
brgb, nindex);
nindex += 4;
}
}
image = Toolkit.getDefaultToolkit().createImage
(new MemoryImageSource(bh.nwidth, bh.nheight,
ndata, 0, bh.nwidth));
fs.close();
return (image);
}
/**
*
* readMap24 internal routine to read the bytes in a 24 bit bitmap
*
*
*
* Arguments:
*
* fs - file stream
*
* bh - header struct
*
* Returns:
*
* Image Object, be sure to check for (Image)null !!!!
*
*
*
*/
protected static Image readMap24(FileInputStream fs, BitmapHeader bh)
throws IOException
{
Image image;
// No Palatte data for 24-bit format but scan lines are
// padded out to even 4-byte boundaries.
int npad = (bh.nsizeimage / bh.nheight) - bh.nwidth * 3;
int ndata[] = new int[bh.nheight * bh.nwidth];
byte brgb[] = new byte[(bh.nwidth + npad) * 3 * bh.nheight];
fs.read(brgb, 0, (bh.nwidth + npad) * 3 * bh.nheight);
int nindex = 0;
for (int j = 0; j < bh.nheight; j++)
{
for (int i = 0; i < bh.nwidth; i++)
{
ndata[bh.nwidth * (bh.nheight - j - 1) + i] = constructInt3(
brgb, nindex);
nindex += 3;
}
nindex += npad;
}
image = Toolkit.getDefaultToolkit().createImage
(new MemoryImageSource(bh.nwidth, bh.nheight,
ndata, 0, bh.nwidth));
fs.close();
return (image);
}
/**
*
* readMap8 internal routine to read the bytes in a 8 bit bitmap
*
*
*
* Arguments:
*
* fs - file stream
*
* bh - header struct
*
* Returns:
*
* Image Object, be sure to check for (Image)null !!!!
*
*
*
*/
protected static Image readMap8(FileInputStream fs, BitmapHeader bh)
throws IOException
{
Image image;
// Have to determine the number of colors, the clrsused
// parameter is dominant if it is greater than zero. If
// zero, calculate colors based on bitsperpixel.
int nNumColors = 0;
if (bh.nclrused > 0)
{
nNumColors = bh.nclrused;
}
else
{
nNumColors = (1 & 0xff) << bh.nbitcount;
}
// System.out.println("The number of Colors is"+nNumColors);
// Some bitmaps do not have the sizeimage field calculated
// Ferret out these cases and fix 'em.
if (bh.nsizeimage == 0)
{
bh.nsizeimage = ((((bh.nwidth * bh.nbitcount) + 31) & ~31) >> 3);
bh.nsizeimage *= bh.nheight;
// System.out.println("nsizeimage (backup) is"+nsizeimage);
}
// Read the palatte colors.
int npalette[] = new int[nNumColors];
byte bpalette[] = new byte[nNumColors * 4];
fs.read(bpalette, 0, nNumColors * 4);
int nindex8 = 0;
for (int n = 0; n < nNumColors; n++)
{
npalette[n] = constructInt3(bpalette, nindex8);
nindex8 += 4;
}
// Read the image data (actually indices into the palette)
// Scan lines are still padded out to even 4-byte
// boundaries.
int npad8 = (bh.nsizeimage / bh.nheight) - bh.nwidth;
// System.out.println("nPad is:"+npad8);
int ndata8[] = new int[bh.nwidth * bh.nheight];
byte bdata[] = new byte[(bh.nwidth + npad8) * bh.nheight];
fs.read(bdata, 0, (bh.nwidth + npad8) * bh.nheight);
nindex8 = 0;
for (int j8 = 0; j8 < bh.nheight; j8++)
{
for (int i8 = 0; i8 < bh.nwidth; i8++)
{
ndata8[bh.nwidth * (bh.nheight - j8 - 1) + i8] =
npalette[((int) bdata[nindex8] & 0xff)];
nindex8++;
}
nindex8 += npad8;
}
image = Toolkit.getDefaultToolkit().createImage
(new MemoryImageSource(bh.nwidth, bh.nheight,
ndata8, 0, bh.nwidth));
return (image);
}
/**
*
* load method - see read for details
*
*
*
* Arguments:
*
* sdir and sfile are the result of the FileDialog()
*
* getDirectory() and getFile() methods.
*
*
*
* Returns:
*
* Image Object, be sure to check for (Image)null !!!!
*
*
*
*/
public static Image load(String sdir, String sfile) {
return (load(sdir + sfile));
}
/**
*
* load method - see read for details
*
*
*
* Arguments:
*
* sdir - full path name
*
*
*
* Returns:
*
* Image Object, be sure to check for (Image)null !!!!
*
*
*
*/
public static Image load(String sdir)
{
try
{
FileInputStream fs = new FileInputStream(sdir);
return (read(fs));
}
catch (IOException ex) {
return (null);
}
}
public static void main(String[] args) throws IOException
{
if (args.length == 0) {
System.out.println("Usage >java BMPLoader ImageFile.bmp");
System.exit(0);
}
FileInputStream in = new FileInputStream(args[0]);
Image TheImage = read(in);
JFrame TheFrame = new JFrame(args[0]);
JLabel TheLabel = new JLabel(new ImageIcon(TheImage));
TheFrame.getContentPane().add(new JScrollPane(TheLabel));
TheFrame.setSize(300, 300);
TheFrame.setVisible(true);
}
//end class BMPLoader
}