bmp.java

使用java编写的LSB图像信息隐藏算法演示程序

package hideInfo;


import java.awt.Image;
import java.awt.image.*;
import java.awt.Toolkit;
import java.io.*;
import java.net.URL;

public class BMP {

    private java.awt.Image image;
    private BmpFileheader bmp_fileheader = new BmpFileheader();
    private BmpInfoHeader bmp_infoheader = new BmpInfoHeader();
    private BmpPalette bmp_palette;    
    private int width;
    private int height;

    public BMP(File f) {
        try {
            PCBinaryInputStream file = new PCBinaryInputStream(f);
            read(file);
        } catch (IOException e) {
            System.err.println(e);
        }
    }

 
    public BMP(URL url) {
        try {
            PCBinaryInputStream file = new PCBinaryInputStream(url);
            read(file);
        } catch (IOException e) {
            System.err.println(e);
        }
    }

    /**
     * Creates an BMP from the given Image
     */
    public BMP(Image image) {
        this.image=image;
        width=image.getWidth(null);
        height=image.getHeight(null);
        bmp_infoheader.biWidth = (short)width;
        bmp_infoheader.biHeight = (short)height;
        bmp_infoheader.biBitCount = 24;
        bmp_infoheader.biClrUsed = 0;
    }


    public Image getImage() {
        return image;
    }

    public void write(File f) {
        try {
            PCBinaryOutputStream file = new PCBinaryOutputStream(f);
            write(file);
        } catch (IOException e) {
            System.err.println(e);
        }
    }

    /**
     * Saves the BMP in a given file.
     */
    public void write(URL url) {
        try {
            PCBinaryOutputStream file = new PCBinaryOutputStream(url);
            write(file);
        } catch (IOException e) {
            System.err.println(e);
        }
    }

    /**
     * Saves the BMP in a given file.
     */
    void write(PCBinaryOutputStream file) {
        try {
            int rawData[] = new int[width*height];
            PixelGrabber grabber = new PixelGrabber(image, 0, 0, width, height, rawData, 0, width);
            bmp_palette = new BmpPalette(grabber.getColorModel());
                          
            try {
                grabber.grabPixels();
            } catch (InterruptedException e) { System.err.println(e); }

            ColorModel model = grabber.getColorModel();

            bmp_fileheader.bfOffBits = bmp_fileheader.getSize() + 
                                       bmp_infoheader.getSize() +
                                       bmp_palette.getSize();
            int x=0,y=0,i=0,j=0,k=0;
            byte bitmap[];
            int w=width*3;              
            int h=height-1;

            // dword align width            
            if (w%4 != 0) 
                w += (4-(w%4));

            if (model instanceof IndexColorModel) {
                // not tested - (can't get IndexColorModel from PixelGrabber??!)
                bitmap = new byte[width*bmp_infoheader.biHeight];
                for (y=h;y>=0;y--) {
                    i=(h-y)*width;
                    j=y*width;                    
                    for (x=0;x<width;x++) {
                        bitmap[j++]=(byte)(rawData[i+x]);
                    }
                }
                bmp_fileheader.bfSize = bmp_fileheader.bfOffBits + 
                                        width*bmp_infoheader.biHeight;
            }
            else {
                bitmap = new byte[w*bmp_infoheader.biHeight];
                for (y=0;y<height;y++) {
                   i=(h-y)*width;                   
                   j=y*w;                    
                   for (x=0;x<width;x++) {
                       k=i+x;
                       bitmap[j++]=(byte)((model.getBlue(rawData[k]))&0xFF);
                       bitmap[j++]=(byte)((model.getGreen(rawData[k]))&0xFF);
                       bitmap[j++]=(byte)((model.getRed(rawData[k]))&0xFF);
                   }
                }
            }                                   
            rawData = null;
            // bmp_infoheader.biWidth=w;
            bmp_fileheader.bfSize = bmp_fileheader.bfOffBits + w*bmp_infoheader.biHeight;
                        
            bmp_fileheader.write(file);
            bmp_infoheader.write(file);
            bmp_palette.write(file);
            file.writeByteArray(bitmap);            
            bitmap = null;
            file.close();
        } catch (IOException e) { System.err.println(e); }
    }

    /**
     * Read a BMP from a given file.
     */
    void read(PCBinaryInputStream file) {
        int coloursUsed = 0;
        int scanlineSize = 0;
        int bitplaneSize = 0;
        byte [] rawData = null;

        try {
            bmp_fileheader.read(file);
            bmp_infoheader.read(file);

            if (bmp_infoheader.biClrUsed != 0)
                coloursUsed = bmp_infoheader.biClrUsed;
            else if (bmp_infoheader.biBitCount < 16)
                coloursUsed = 1 << bmp_infoheader.biBitCount;

            bmp_palette = new BmpPalette(coloursUsed);
            bmp_palette.read(file);

            long skip =  bmp_fileheader.bfOffBits - 
                        (bmp_fileheader.getSize()+
                         bmp_infoheader.getSize()+
                         bmp_palette.getSize());
                         
            if (skip > 0) {
                file.skip(skip);
            }

            scanlineSize = ((bmp_infoheader.biWidth*bmp_infoheader.biBitCount+31)/32)*4;

            if (bmp_infoheader.biSizeImage != 0)
                bitplaneSize = bmp_infoheader.biSizeImage;
            else
                bitplaneSize = scanlineSize * bmp_infoheader.biHeight;

            rawData = new byte[bitplaneSize];
            file.readByteArray(rawData);
            file.close();

        } catch (IOException e) {
            System.err.println(e);
        }

        if (rawData != null) {
            if (bmp_infoheader.biBitCount > 8) {
                image = unpack24(rawData, scanlineSize);
            }
            else {
                image = unpack08(rawData, scanlineSize);
            }
        }
        rawData = null;
    }

    Image unpack24(byte [] rawData, int scanlineSize) {
        int b=0, k=0, x=0, y=0;
        int [] data = new int[bmp_infoheader.biWidth * bmp_infoheader.biHeight];
        try {
            for (y=0; y < bmp_infoheader.biHeight; y++) {
              b=(bmp_infoheader.biHeight-1-y)*bmp_infoheader.biWidth;
              k=y*scanlineSize;
              for (x=0; x < bmp_infoheader.biWidth; x++) {
                data[x+b] = 0xFF000000 |
                         (((int)(rawData[k++])) & 0xFF) |
                         (((int)(rawData[k++])) & 0xFF) << 8 |
                         (((int)(rawData[k++])) & 0xFF) << 16;
              }
            }
        }catch (Exception e) {};
        return Toolkit.getDefaultToolkit().createImage(new MemoryImageSource(bmp_infoheader.biWidth, bmp_infoheader.biHeight, ColorModel.getRGBdefault(), data, 0, bmp_infoheader.biWidth));
    }

    Image unpack08(byte [] rawData, int scanlineSize) {
        int b=0, k=0, i=0, x=0, y=0;
        byte [] data = new byte[bmp_infoheader.biWidth * bmp_infoheader.biHeight];
        try {
        if (bmp_infoheader.biBitCount == 1) {            
            for (y=0; y < bmp_infoheader.biHeight; y++) {
              b=(bmp_infoheader.biHeight-1-y)*bmp_infoheader.biWidth;
              k=y*scanlineSize;
              for (x=0; x < (bmp_infoheader.biWidth-8); x+=8) {
                data[b+x+7] = (byte)((rawData[k]) & 1);
                data[b+x+6] = (byte)((rawData[k] >>> 1) & 1);
                data[b+x+5] = (byte)((rawData[k] >>> 2) & 1);
                data[b+x+4] = (byte)((rawData[k] >>> 3) & 1);
                data[b+x+3] = (byte)((rawData[k] >>> 4) & 1);
                data[b+x+2] = (byte)((rawData[k] >>> 5) & 1);
                data[b+x+1] = (byte)((rawData[k] >>> 6) & 1);
                data[b+x]   = (byte)((rawData[k] >>> 7) & 1);