jpegencoder.java

基于JPEG图像的数字密写方法 F5算法的JAVA程序

                        System.out.println("IO Error: " + e.getMessage());
                }
                if (c == 0xFF) {
                        try
                        {
                                outStream.write(0);
                        }
                        catch (IOException e) {
                                System.out.println("IO Error: " + e.getMessage());
                        }
                }
                PutBuffer <<= 8;
                PutBits -= 8;
        }
        bufferPutBuffer = PutBuffer;
        bufferPutBits = PutBits;

        }

        void flushBuffer(BufferedOutputStream outStream) {
                int PutBuffer = bufferPutBuffer;
                int PutBits = bufferPutBits;
                while (PutBits >= 8) {
                        int c = ((PutBuffer >> 16) & 0xFF);
                        try
                        {
                                outStream.write(c);
                        }
                        catch (IOException e) {
                                System.out.println("IO Error: " + e.getMessage());
                        }
                        if (c == 0xFF) {
                                try {
                                        outStream.write(0);
                                }
                                catch (IOException e) {
                                        System.out.println("IO Error: " + e.getMessage());
                                }
                        }
                        PutBuffer <<= 8;
                        PutBits -= 8;
                }
                if (PutBits > 0) {
                        int c = ((PutBuffer >> 16) & 0xFF);
                        try
                        {
                                outStream.write(c);
                        }
                        catch (IOException e) {
                                System.out.println("IO Error: " + e.getMessage());
                        }
                }
        }

    /*
    * Initialisation of the Huffman codes for Luminance and Chrominance.
    * This code results in the same tables created in the IJG Jpeg-6a
    * library.
    */

    public void initHuf()
    {
        DC_matrix0=new int[12][2];
        DC_matrix1=new int[12][2];
        AC_matrix0=new int[255][2];
        AC_matrix1=new int[255][2];
        DC_matrix = new Object[2];
        AC_matrix = new Object[2];
        int p, l, i, lastp, si, code;
        int[] huffsize = new int[257];
        int[] huffcode= new int[257];

        /*
        * init of the DC values for the chrominance
        * [][0] is the code   [][1] is the number of bit
        */

        p = 0;
        for (l = 1; l <= 16; l++)
        {
                for (i = 1; i <= bitsDCchrominance[l]; i++)
                {
                        huffsize[p++] = l;
                }
        }
        huffsize[p] = 0;
        lastp = p;

        code = 0;
        si = huffsize[0];
        p = 0;
        while(huffsize[p] != 0)
        {
                while(huffsize[p] == si)
                {
                        huffcode[p++] = code;
                        code++;
                }
                code <<= 1;
                si++;
        }

        for (p = 0; p < lastp; p++)
        {
                DC_matrix1[valDCchrominance[p]][0] = huffcode[p];
                DC_matrix1[valDCchrominance[p]][1] = huffsize[p];
        }

        /*
        * Init of the AC hufmann code for the chrominance
        * matrix [][][0] is the code & matrix[][][1] is the number of bit needed
        */

        p = 0;
        for (l = 1; l <= 16; l++)
        {
                for (i = 1; i <= bitsACchrominance[l]; i++)
                {
                        huffsize[p++] = l;
                }
        }
        huffsize[p] = 0;
        lastp = p;

        code = 0;
        si = huffsize[0];
        p = 0;
        while(huffsize[p] != 0)
        {
                while(huffsize[p] == si)
                {
                        huffcode[p++] = code;
                        code++;
                }
                code <<= 1;
                si++;
        }

        for (p = 0; p < lastp; p++)
        {
                AC_matrix1[valACchrominance[p]][0] = huffcode[p];
                AC_matrix1[valACchrominance[p]][1] = huffsize[p];
        }

        /*
        * init of the DC values for the luminance
        * [][0] is the code   [][1] is the number of bit
        */
        p = 0;
        for (l = 1; l <= 16; l++)
        {
                for (i = 1; i <= bitsDCluminance[l]; i++)
                {
                        huffsize[p++] = l;
                }
        }
        huffsize[p] = 0;
        lastp = p;

        code = 0;
        si = huffsize[0];
        p = 0;
        while(huffsize[p] != 0)
        {
                while(huffsize[p] == si)
                {
                        huffcode[p++] = code;
                        code++;
                }
                code <<= 1;
                si++;
        }

        for (p = 0; p < lastp; p++)
        {
                DC_matrix0[valDCluminance[p]][0] = huffcode[p];
                DC_matrix0[valDCluminance[p]][1] = huffsize[p];
        }

        /*
        * Init of the AC hufmann code for luminance
        * matrix [][][0] is the code & matrix[][][1] is the number of bit
        */

        p = 0;
        for (l = 1; l <= 16; l++)
        {
                for (i = 1; i <= bitsACluminance[l]; i++)
                {
                        huffsize[p++] = l;
                }
        }
        huffsize[p] = 0;
        lastp = p;

        code = 0;
        si = huffsize[0];
        p = 0;
        while(huffsize[p] != 0)
        {
                while(huffsize[p] == si)
                {
                        huffcode[p++] = code;
                        code++;
                }
                code <<= 1;
                si++;
        }
        for (int q = 0; q < lastp; q++)
        {
                AC_matrix0[valACluminance[q]][0] = huffcode[q];
                AC_matrix0[valACluminance[q]][1] = huffsize[q];
        } 

        DC_matrix[0] = DC_matrix0;
        DC_matrix[1] = DC_matrix1;
        AC_matrix[0] = AC_matrix0;
        AC_matrix[1] = AC_matrix1;
    }

}

/*
 * JpegInfo - Given an image, sets default information about it and divides
 * it into its constituant components, downsizing those that need to be.
 */

class JpegInfo
{
    String Comment;
    public Image imageobj;
    public int imageHeight;
    public int imageWidth;
    public int BlockWidth[];
    public int BlockHeight[];

// the following are set as the default
    public int Precision = 8;
    public int NumberOfComponents = 3;
    public Object Components[];
    public int[] CompID = {1, 2, 3};
    //public int[] HsampFactor = {1, 1, 1};
    //public int[] VsampFactor = {1, 1, 1};
    public int[] HsampFactor = {2, 1, 1};
    public int[] VsampFactor = {2, 1, 1};
    public int[] QtableNumber = {0, 1, 1};
    public int[] DCtableNumber = {0, 1, 1};
    public int[] ACtableNumber = {0, 1, 1};
    public boolean[] lastColumnIsDummy = {false, false, false};
    public boolean[] lastRowIsDummy = {false, false, false};
    public int Ss = 0;
    public int Se = 63;
    public int Ah = 0;
    public int Al = 0;
    public int compWidth[], compHeight[];
    public int MaxHsampFactor;
    public int MaxVsampFactor;


    public JpegInfo(Image image, String comment)
    {
        Components = new Object[NumberOfComponents];
        compWidth = new int[NumberOfComponents];
        compHeight = new int[NumberOfComponents];
        BlockWidth = new int[NumberOfComponents];
        BlockHeight = new int[NumberOfComponents];
        imageobj = image;
        imageWidth = image.getWidth(null);
        imageHeight = image.getHeight(null);
        //Comment = "JPEG Encoder Copyright 1998, James R. Weeks and BioElectroMech.  ";
        Comment = comment;
        getYCCArray();
    }

    public void setComment(String comment) {
        Comment.concat(comment);
    }

    public String getComment() {
        return Comment;
    }

    /*
     * This method creates and fills three arrays, Y, Cb, and Cr using the
     * input image.
     */

    private void getYCCArray()
    {
        int values[] = new int[imageWidth * imageHeight];
        int r, g, b, y, x;
// In order to minimize the chance that grabPixels will throw an exception
// it may be necessary to grab some pixels every few scanlines and process
// those before going for more.  The time expense may be prohibitive.
// However, for a situation where memory overhead is a concern, this may be
// the only choice.
    	PixelGrabber grabber = new PixelGrabber(imageobj.getSource(), 0, 0, imageWidth, imageHeight, values, 0, imageWidth);
        MaxHsampFactor = 1;
        MaxVsampFactor = 1;
        for (y = 0; y < NumberOfComponents; y++) {
                MaxHsampFactor = Math.max(MaxHsampFactor, HsampFactor[y]);
                MaxVsampFactor = Math.max(MaxVsampFactor, VsampFactor[y]);
        }
if(false) {
        for (y = 0; y < NumberOfComponents; y++) {
                compWidth[y] = (((imageWidth%8 != 0) ? ((int) Math.ceil((double) imageWidth/8.0))*8 : imageWidth)/MaxHsampFactor)*HsampFactor[y];
                if (compWidth[y] != ((imageWidth/MaxHsampFactor)*HsampFactor[y])) {
                        lastColumnIsDummy[y] = true;
                }
                // results in a multiple of 8 for compWidth
                // this will make the rest of the program fail for the unlikely
                // event that someone tries to compress an 16 x 16 pixel image
                // which would of course be worse than pointless
                BlockWidth[y] = (int) Math.ceil((double) compWidth[y]/8.0);
                compHeight[y] = (((imageHeight%8 != 0) ? ((int) Math.ceil((double) imageHeight/8.0))*8: imageHeight)/MaxVsampFactor)*VsampFactor[y];
                if (compHeight[y] != ((imageHeight/MaxVsampFactor)*VsampFactor[y])) {
                        lastRowIsDummy[y] = true;
                }
                BlockHeight[y] = (int) Math.ceil((double) compHeight[y]/8.0);
        }
} else {
        for (y = 0; y < NumberOfComponents; y++) {
                compWidth[y] = ((
		(imageWidth%8 != 0) ?
		((int) Math.ceil((double) imageWidth/8.0))*8 :
		imageWidth)
		/MaxHsampFactor)*HsampFactor[y];
                if (compWidth[y] != ((imageWidth/MaxHsampFactor)*HsampFactor[y])) {
                        lastColumnIsDummy[y] = true;
                }
                // results in a multiple of 8 for compWidth
                // this will make the rest of the program fail for the unlikely
                // event that someone tries to compress an 16 x 16 pixel image
                // which would of course be worse than pointless
                BlockWidth[y] = (int) Math.ceil((double) compWidth[y]/8.0);
                compHeight[y] = ((
		(imageHeight%8 != 0) ?
		((int) Math.ceil((double) imageHeight/8.0))*8:
		imageHeight)
		/MaxVsampFactor)*VsampFactor[y];
                if (compHeight[y] != ((imageHeight/MaxVsampFactor)*VsampFactor[y])) {
                        lastRowIsDummy[y] = true;
                }
                BlockHeight[y] = (int) Math.ceil((double) compHeight[y]/8.0);
        }
}
        try
    	{
    	    if(grabber.grabPixels() != true)
    	    {
    		    try
    		    {
    		        throw new AWTException("Grabber returned false: " + grabber.getStatus());
    		    }
    		    catch (Exception e) {};
            }
    	}
    	catch (InterruptedException e) {};
        float Y[][] = new float[compHeight[0]][compWidth[0]];
        float Cr1[][] = new float[compHeight[0]][compWidth[0]];
        float Cb1[][] = new float[compHeight[0]][compWidth[0]];
        float Cb2[][] = new float[compHeight[1]][compWidth[1]];
        float Cr2[][] = new float[compHeight[2]][compWidth[2]];
        int index = 0;
        for (y = 0; y < imageHeight; ++y)
    	{
            for (x = 0; x < imageWidth; ++x)
    	    {
                r = ((values[index] >> 16) & 0xff);
                g = ((values[index] >> 8) & 0xff);
                b = (values[index] & 0xff);

// The following three lines are a more correct color conversion but
// the current conversion technique is sufficient and results in a higher
// compression rate.
//                Y[y][x] = 16 + (float)(0.8588*(0.299 * (float)r + 0.587 * (float)g + 0.114 * (float)b ));
//                Cb1[y][x] = 128 + (float)(0.8784*(-0.16874 * (float)r - 0.33126 * (float)g + 0.5 * (float)b));
//                Cr1[y][x] = 128 + (float)(0.8784*(0.5 * (float)r - 0.41869 * (float)g - 0.08131 * (float)b));
                Y[y][x] = (float)((0.299 * (float)r + 0.587 * (float)g + 0.114 * (float)b));
                Cb1[y][x] = 128 + (float)((-0.16874 * (float)r - 0.33126 * (float)g + 0.5 * (float)b));
                Cr1[y][x] = 128 + (float)((0.5 * (float)r - 0.41869 * (float)g - 0.08131 * (float)b));
                index++;
    	    }
    	}

// Need a way to set the H and V sample factors before allowing downsampling.
// For now (04/04/98) downsampling must be hard coded.
// Until a better downsampler is implemented, this will not be done.
// Downsampling is currently supported.  The downsampling method here
// is a simple box filter.

        Components[0] = Y;
	if (false) {
	//        Cb2 = DownSample(Cb1, 1);
		Components[1] = Cb1;
	//        Cr2 = DownSample(Cr1, 2);
		Components[2] = Cr1;
	} else {
	        Cb2 = DownSample(Cb1, 1);
		Components[1] = Cb2;
	        Cr2 = DownSample(Cr1, 2);
		Components[2] = Cr2;
	}
    }

    float[][] DownSample(float[][] C, int comp)
    {
        int inrow, incol;
        int outrow, outcol;
        float output[][];
        float temp;
        int bias;
        inrow = 0;
        incol = 0;
        output = new float[compHeight[comp]][compWidth[comp]];
        for (outrow = 0; outrow < compHeight[comp]; outrow++) {
                bias = 1;
                for (outcol = 0; outcol < compWidth[comp]; outcol++) {
//System.out.println("outcol="+outcol);
			temp = C[inrow][incol++];	// 00
			temp += C[inrow++][incol--];	// 01
			temp += C[inrow][incol++];	// 10
			temp += C[inrow--][incol++] + (float)bias; // 11 -> 02
                        output[outrow][outcol] = temp/(float)4.0;
                        bias ^= 3;
                }
                inrow += 2;
                incol = 0;
        }
        return output;
    }
}