我想将canvas里头的图画保存成为gif或jpg图象

[dgsrest]

请详细说明一下

[207]

给个例子，你再想一下吧
package testPrint;

import java.awt.*;
import java.io.*;
import java.awt.image.*;

public class BMPFile extends Component {

//--- Private constants
private final static int BITMAPFILEHEADER_SIZE = 14;
private final static int BITMAPINFOHEADER_SIZE = 40;

//--- Private variable declaration

//--- Bitmap file header
private byte bitmapFileHeader [] = new byte [14];
private byte bfType [] = {'B', 'M'};
private int bfSize = 0;
private int bfReserved1 = 0;
private int bfReserved2 = 0;
private int bfOffBits = BITMAPFILEHEADER_SIZE + BITMAPINFOHEADER_SIZE;

//--- Bitmap info header
private byte bitmapInfoHeader [] = new byte [40];
private int biSize = BITMAPINFOHEADER_SIZE;
private int biWidth = 0;
private int biHeight = 0;
private int biPlanes = 1;
private int biBitCount = 24;
private int biCompression = 0;
private int biSizeImage = 0x030000;
private int biXPelsPerMeter = 0x0;
private int biYPelsPerMeter = 0x0;
private int biClrUsed = 0;
private int biClrImportant = 0;

//--- Bitmap raw data
private int bitmap [];

//--- File section
private FileOutputStream fo;

//--- Default constructor
public BMPFile() {

}

public void saveBitmap (String parFilename, Image parImage, int
parWidth, int parHeight) {

try {
fo = new FileOutputStream (parFilename);
save (parImage, parWidth, parHeight);
fo.close ();
}
catch (Exception saveEx) {
saveEx.printStackTrace ();
}

}

/*
* The saveMethod is the main method of the process. This method
* will call the convertImage method to convert the memory image to
* a byte array; method writeBitmapFileHeader creates and writes
* the bitmap file header; writeBitmapInfoHeader creates the
* information header; and writeBitmap writes the image.
*
*/
private void save (Image parImage, int parWidth, int parHeight) {

try {
convertImage (parImage, parWidth, parHeight);
writeBitmapFileHeader ();
writeBitmapInfoHeader ();
writeBitmap ();
}
catch (Exception saveEx) {
saveEx.printStackTrace ();
}
}

/*
* convertImage converts the memory image to the bitmap format (BRG).
* It also computes some information for the bitmap info header.
*
*/
private boolean convertImage (Image parImage, int parWidth, int parHeight) {

int pad;
bitmap = new int [parWidth * parHeight];

PixelGrabber pg = new PixelGrabber (parImage, 0, 0, parWidth, parHeight,
bitmap, 0, parWidth);

try {
pg.grabPixels ();
}
catch (InterruptedException e) {
e.printStackTrace ();
return (false);
}
pad = (parWidth * 3) % 4;
if (pad != 0)
pad = (4 - pad) * parHeight;
biSizeImage = ((parWidth * parHeight) * 3) + pad;
bfSize = biSizeImage + BITMAPFILEHEADER_SIZE +
BITMAPINFOHEADER_SIZE;
biWidth = parWidth;
biHeight = parHeight;

return (true);
}

/*
* writeBitmap converts the image returned from the pixel grabber to
* the format required. Remember: scan lines are inverted in
* a bitmap file!
*
* Each scan line must be padded to an even 4-byte boundary.
*/
private void writeBitmap () {

int size;
int value;
int j;
int i;
int rowCount;
int rowIndex;
int lastRowIndex;
int pad;
int padCount;
byte rgb [] = new byte [3];
// if a scanline is not time of 4, add some bytes
size = (biWidth * biHeight) - 1;
pad = ((biWidth * 3) % 4);
if (pad != 0)
pad = 4 - pad;
rowCount = 1;
padCount = 0;
rowIndex = size - biWidth;
lastRowIndex = rowIndex;

try {
for (j = 0; j < size; j++) {
value = bitmap [rowIndex];
rgb [0] = (byte) (value & 0xFF);
rgb [1] = (byte) ((value >> 8) & 0xFF);
rgb [2] = (byte) ((value >> 16) & 0xFF);
fo.write (rgb);
if (rowCount == biWidth) {
padCount += pad;
for (i = 1; i <= pad; i++)
fo.write (0x00);
rowCount = 1;
rowIndex = lastRowIndex - biWidth;
lastRowIndex = rowIndex;
}
else
rowCount++;
rowIndex++;
}

//--- Update the size of the file
bfSize += padCount - pad;
biSizeImage += padCount - pad;
}
catch (Exception wb) {
wb.printStackTrace ();
}

}

/*
* writeBitmapFileHeader writes the bitmap file header to the file.
*
*/
private void writeBitmapFileHeader () {

try {
fo.write (bfType);
fo.write (intToDWord (bfSize));
fo.write (intToWord (bfReserved1));
fo.write (intToWord (bfReserved2));
fo.write (intToDWord (bfOffBits));

}
catch (Exception wbfh) {
wbfh.printStackTrace ();
}

}

/*
*
* writeBitmapInfoHeader writes the bitmap information header
* to the file.
*
*/

private void writeBitmapInfoHeader () {

try {
fo.write (intToDWord (biSize));
fo.write (intToDWord (biWidth));
fo.write (intToDWord (biHeight));
fo.write (intToWord (biPlanes));
fo.write (intToWord (biBitCount));
fo.write (intToDWord (biCompression));
fo.write (intToDWord (biSizeImage));
fo.write (intToDWord (biXPelsPerMeter));
fo.write (intToDWord (biYPelsPerMeter));
fo.write (intToDWord (biClrUsed));
fo.write (intToDWord (biClrImportant));
}
catch (Exception wbih) {
wbih.printStackTrace ();
}

}

/*
*
* intToWord converts an int to a word, where the return
* value is stored in a 2-byte array.
*
*/
private byte [] intToWord (int parValue) {

byte retValue [] = new byte [2];

retValue [0] = (byte) (parValue & 0x00FF);
retValue [1] = (byte) ((parValue >> 8) & 0x00FF);

return (retValue);

}

/*
*
* intToDWord converts an int to a double word, where the return
* value is stored in a 4-byte array.
*
*/
private byte [] intToDWord (int parValue) {

byte retValue [] = new byte [4];

retValue [0] = (byte) (parValue & 0x00FF);
retValue [1] = (byte) ((parValue >> 8) & 0x000000FF);
retValue [2] = (byte) ((parValue >> 16) & 0x000000FF);
retValue [3] = (byte) ((parValue >> 24) & 0x000000FF);

return (retValue);

}

}

[zkhj]

up

[dgsrest]

能具体说一下怎么实现吗？

[dgsrest]

又大虾帮帮忙吗？