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    /**
    loadbitmap() method converted from Windows C code.
    Reads only uncompressed 24- and 8-bit images.  Tested with
    images saved using Microsoft Paint in Windows 95.  If the image
    is not a 24- or 8-bit image, the program refuses to even try.
    I guess one could include 4-bit images by masking the byte
    by first 1100 and then 0011.  I am not really 
    interested in such images.  If a compressed image is attempted,
    the routine will probably fail by generating an IOException.
    Look for variable ncompression to be different from 0 to indicate
    compression is present.
    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 Image loadbitmap (String sdir, String sfile)
    {
    Image image;
    System.out.println("loading:"+sdir+sfile);
    try
        {
        FileInputStream fs=new FileInputStream(sdir+sfile);
        int bflen=14;  // 14 byte BITMAPFILEHEADER
        byte bf[]=new byte[bflen];
        fs.read(bf,0,bflen);
        int bilen=40; // 40-byte BITMAPINFOHEADER
        byte bi[]=new byte[bilen];
        fs.read(bi,0,bilen);
        // Interperet data.
        int nsize = (((int)bf[5]&0xff)<<24) 
        | (((int)bf[4]&0xff)<<16)
        | (((int)bf[3]&0xff)<<8)
        | (int)bf[2]&0xff;
        System.out.println("File type is :"+(char)bf[0]+(char)bf[1]);
        System.out.println("Size of file is :"+nsize);
        int nbisize = (((int)bi[3]&0xff)<<24)
        | (((int)bi[2]&0xff)<<16)
        | (((int)bi[1]&0xff)<<8)
        | (int)bi[0]&0xff;
        System.out.println("Size of bitmapinfoheader is :"+nbisize);
        int nwidth = (((int)bi[7]&0xff)<<24)
        | (((int)bi[6]&0xff)<<16)
        | (((int)bi[5]&0xff)<<8)
        | (int)bi[4]&0xff;
        System.out.println("Width is :"+nwidth);
        int nheight = (((int)bi[11]&0xff)<<24)
        | (((int)bi[10]&0xff)<<16)
        | (((int)bi[9]&0xff)<<8)
        | (int)bi[8]&0xff;
        System.out.println("Height is :"+nheight);
        int nplanes = (((int)bi[13]&0xff)<<8) | (int)bi[12]&0xff;
        System.out.println("Planes is :"+nplanes);
        int nbitcount = (((int)bi[15]&0xff)<<8) | (int)bi[14]&0xff;
        System.out.println("BitCount is :"+nbitcount);
        // Look for non-zero values to indicate compression
        int ncompression = (((int)bi[19])<<24)
        | (((int)bi[18])<<16)
        | (((int)bi[17])<<8)
        | (int)bi[16];
        System.out.println("Compression is :"+ncompression);
        int nsizeimage = (((int)bi[23]&0xff)<<24)
        | (((int)bi[22]&0xff)<<16)
        | (((int)bi[21]&0xff)<<8)
        | (int)bi[20]&0xff;
        System.out.println("SizeImage is :"+nsizeimage);
        int nxpm = (((int)bi[27]&0xff)<<24)
        | (((int)bi[26]&0xff)<<16)
        | (((int)bi[25]&0xff)<<8)
        | (int)bi[24]&0xff;
        System.out.println("X-Pixels per meter is :"+nxpm);
        int nypm = (((int)bi[31]&0xff)<<24)
        | (((int)bi[30]&0xff)<<16)
        | (((int)bi[29]&0xff)<<8)
        | (int)bi[28]&0xff;
        System.out.println("Y-Pixels per meter is :"+nypm);
        int nclrused = (((int)bi[35]&0xff)<<24)
        | (((int)bi[34]&0xff)<<16)
        | (((int)bi[33]&0xff)<<8)
        | (int)bi[32]&0xff;
        System.out.println("Colors used are :"+nclrused);
        int nclrimp = (((int)bi[39]&0xff)<<24)
        | (((int)bi[38]&0xff)<<16)
        | (((int)bi[37]&0xff)<<8)
        | (int)bi[36]&0xff;
        System.out.println("Colors important are :"+nclrimp);
        if (nbitcount==24)
        {
        // No Palatte data for 24-bit format but scan lines are
        // padded out to even 4-byte boundaries.
        int npad = (nsizeimage / nheight) - nwidth * 3;
        int ndata[] = new int [nheight * nwidth];
        byte brgb[] = new byte [( nwidth + npad) * 3 * nheight];
        fs.read (brgb, 0, (nwidth + npad) * 3 * nheight);
        int nindex = 0;
        for (int j = 0; j < nheight; j++)
            {
            for (int i = 0; i < nwidth; i++)
            {
            ndata [nwidth * (nheight - j - 1) + i] =
                (255&0xff)<<24
                | (((int)brgb[nindex+2]&0xff)<<16)
                | (((int)brgb[nindex+1]&0xff)<<8)
                | (int)brgb[nindex]&0xff;
            // System.out.println("Encoded Color at ("
                +i+","+j+")is:"+nrgb+" (R,G,B)= ("
                +((int)(brgb[2]) & 0xff)+","
                +((int)brgb[1]&0xff)+","
                +((int)brgb[0]&0xff)+")");
            nindex += 3;
            }
            nindex += npad;
            }
        image = createImage
            ( new MemoryImageSource (nwidth, nheight,
                         ndata, 0, nwidth));
        }
        else if (nbitcount == 8)
        {
        // 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 (nclrused > 0)
            {
            nNumColors = nclrused;
            }
        else
            {
            nNumColors = (1&0xff)<<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 (nsizeimage == 0)
            {
            nsizeimage = ((((nwidth*nbitcount)+31) & 31 ) >> 3);
            nsizeimage *= 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] = (255&0xff)<<24
            | (((int)bpalette[nindex8+2]&0xff)<<16)
            | (((int)bpalette[nindex8+1]&0xff)<<8)
            | (int)bpalette[nindex8]&0xff;
            // System.out.println ("Palette Color "+n
            +" is:"+npalette[n]+" (res,R,G,B)= ("
            +((int)(bpalette[nindex8+3]) & 0xff)+","
            +((int)(bpalette[nindex8+2]) & 0xff)+","
            +((int)bpalette[nindex8+1]&0xff)+","
            +((int)bpalette[nindex8]&0xff)+")");
            nindex8 += 4;
            }
        // Read the image data (actually indices into the palette)
        // Scan lines are still padded out to even 4-byte
        // boundaries.
        int npad8 = (nsizeimage / nheight) - nwidth;
        System.out.println("nPad is:"+npad8);
        int  ndata8[] = new int [nwidth*nheight];
        byte bdata[] = new byte [(nwidth+npad8)*nheight];
        fs.read (bdata, 0, (nwidth+npad8)*nheight);
        nindex8 = 0;
        for (int j8 = 0; j8 < nheight; j8++)
            {
            for (int i8 = 0; i8 < nwidth; i8++)
            {
            ndata8 [nwidth*(nheight-j8-1)+i8] =
                npalette [((int)bdata[nindex8]&0xff)];
            nindex8++;
            }
            nindex8 += npad8;
            }
        image = createImage
            ( new MemoryImageSource (nwidth, nheight,
                         ndata8, 0, nwidth));
        }
        else
        {
        System.out.println ("Not a 24-bit or 8-bit Windows Bitmap, aborting...");
        image = (Image)null;
        }
        fs.close();
        return image;
        }
    catch (Exception e)
        {
        System.out.println("Caught exception in loadbitmap!");
        }
    return (Image) null;
    }

reading imagesBy Anonymous on March 28, 2009, 11:59 amreading images

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