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。如果 clrsused 参数大于 0，

// 则颜色数由它决定。如果它等于 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

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