printscreen读取位图转为jpeg格式输出
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
