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printscreen读取位图转为jpeg格式输出

 2008-01-05 09:58:18 来源:WEB开发网   
核心提示:package screensaver;import java.awt.*;import java.awt.image.BufferedImage;import java.io.*;import java.util.*;import com.sun.image.codec.jpeg.*;import java.awt.

  package screensaver;
  
  import java.awt.*;
  import java.awt.image.BufferedImage;
  import java.io.*;
  import java.util.*;
  import com.sun.image.codec.jpeg.*;
  import java.awt.Image;
  import java.awt.Toolkit;
  import java.awt.image.BufferedImage;
  import java.awt.image.MemoryImageSource;
  import java.io.FileInputStream;
  import java.io.FileOutputStream;
  import com.sun.image.codec.jpeg.JPEGCodec;
  import com.sun.image.codec.jpeg.JPEGImageEncoder;
  
  public class ScreenPicSaver
  {
   MediaTracker tracker = new MediaTracker(new Component()
   {});
  
   public ScreenPicSaver()
   {}
  
   public Image loadbitmap(String sdir, String sfile) //读取8位或24位的位图文件
   {
    Image image;
    System.out.PRintln("loading:" + sdir + sfile);
    try
    {
     FileInputStream fs = new FileInputStream(sdir + sfile);
     int bflen = 14; // 14 字节 BITMAPFILEHEADER
     byte bf[] = new byte[bflen];
     fs.read(bf, 0, bflen);
     int bilen = 40; // 40 字节 BITMAPINFOHEADER
     byte bi[] = new byte[bilen];
     fs.read(bi, 0, bilen);
  
     // 解释数据。
     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);
  
     // 查找表明压缩的非零值
     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)
     {
      // 24 位格式不包含调色板数据,但扫描行被补足到
      // 4 个字节。
      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 = Toolkit.getDefaultToolkit().createImage
        (new MemoryImageSource(nwidth, nheight,
                    ndata, 0, nwidth));
     }
     else if (nbitcount == 8)
     {
      // 必须确定颜色数。假如 clrsused 参数大于 0,
      // 则颜色数由它决定。假如它等于 0,则根据
      // bitsperpixel 计算颜色数。
      int nNumColors = 0;
      if (nclrused > 0)
      {
       nNumColors = nclrused;
      }
      else
      {
       nNumColors = (1 & 0xff) < < nbitcount;
      }
      System.out.println("The number of Colors is" + nNumColors);
  
      // 某些位图不计算 sizeimage 域,请找出
      // 这些情况并对它们进行修正。
      if (nsizeimage == 0)
      {
       nsizeimage = ( ( ( (nwidth * nbitcount) + 31) & ~31) >> 3);
       nsizeimage *= nheight;
       System.out.println("nsizeimage (backup) is" + nsizeimage);
      }
  
      // 读取调色板颜色。
      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) bpal

Tags:printscreen 读取 位图

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