android 将bitmap存为 bmp格式图片大小 把bitmap保存成 BMP的格式 并且位深度为1

生成图片的要求：图像格式采用单色位图文件格式(BMP) 要求bmp的位深度为1

参考：

代码有点小瑕疵 ：bitmap的图片宽度要求是：8的整数倍

/**

* 将Bitmap存为 .bmp格式图片

*

* @param bitmap

*/

public void saveBmp(Bitmap bitmap) {

if (bitmap == null)

return;

// 位图大小

int nBmpWidth = bitmap.getWidth();

int nBmpHeight = bitmap.getHeight();

// 图像数据大小

int bufferSize = nBmpHeight * nBmpWidth /8 + 4*2;

try {

// 存储文件名

String filename = Environment.getExternalStorageDirectory().getAbsolutePath() + File.separator + "test.bmp";

File file = new File(filename);

if (!file.exists()) {

file.createNewFile();

}

FileOutputStream fileos = new FileOutputStream(filename);

// bmp文件头

int bfType = 0x4d42;

long bfSize = 14 + 40 + bufferSize;

int bfReserved1 = 0;

int bfReserved2 = 0;

long bfOffBits = 14 + 40;

// 保存bmp文件头

writeWord(fileos, bfType);

writeDword(fileos, bfSize);

writeWord(fileos, bfReserved1);

writeWord(fileos, bfReserved2);

writeDword(fileos, bfOffBits);

// bmp信息头

long biSize = 40L;

long biWidth = nBmpWidth;

long biHeight = nBmpHeight;

int biPlanes = 1;

int biBitCount = 1;

long biCompression = 0L;

long biSizeImage = 0L;

long biXpelsPerMeter = 0L;

long biYPelsPerMeter = 0L;

long biClrUsed = 0L;

long biClrImportant = 0L;

// 保存bmp信息头

writeDword(fileos, biSize);

writeLong(fileos, biWidth);

writeLong(fileos, biHeight);

writeWord(fileos, biPlanes);

writeWord(fileos, biBitCount);

writeDword(fileos, biCompression);

writeDword(fileos, biSizeImage);

writeLong(fileos, biXpelsPerMeter);

writeLong(fileos, biYPelsPerMeter);

writeDword(fileos, biClrUsed);

writeDword(fileos, biClrImportant);

//调色板

byte buf[] = new byte[]{(byte) 0xff, (byte) 0xff, (byte) 0xff,0, 0, 0, 0, 0};

fileos.write(buf);

// 像素扫描

int bw = nBmpWidth/8;

byte recv[] = new byte[bw*nBmpHeight];

int[] pixels = new int[nBmpWidth * nBmpHeight];

bitmap.getPixels(pixels, 0, nBmpWidth, 0, 0, nBmpWidth, nBmpHeight);

for(int i = nBmpHeight - 1, ii = 0; i >= 0; i--, ii++){

for(int j = 0; j < nBmpWidth; j++){

int clr = pixels[nBmpWidth * i + j];

int red = (clr & 0x00ff0000) >> 16;

int green = (clr & 0x0000ff00) >> 8;

int blue = clr & 0x000000ff;

byte gray = (RGB2Gray(red, green, blue));

recv[(nBmpWidth * ii + j) / 8] = (byte) (recv[(nBmpWidth * ii + j) / 8] | (gray << (7 - ((nBmpWidth * ii + j) % 8))));

}

}

fileos.write(recv);

fileos.flush();

fileos.close();

} catch (FileNotFoundException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}

}

private byte RGB2Gray(int r, int g, int b) {

return (false ? ((int) (0.29900 * r + 0.58700 * g + 0.11400 * b) > 200)

: ((int) (0.29900 * r + 0.58700 * g + 0.11400 * b) < 200)) ? (byte) 1 : (byte) 0;

}

protected void writeWord(FileOutputStream stream, int value) throws IOException {

byte[] b = new byte[2];

b[0] = (byte) (value & 0xff);

b[1] = (byte) (value >> 8 & 0xff);

stream.write(b);

}

protected void writeDword(FileOutputStream stream, long value) throws IOException {

byte[] b = new byte[4];

b[0] = (byte) (value & 0xff);

b[1] = (byte) (value >> 8 & 0xff);

b[2] = (byte) (value >> 16 & 0xff);

b[3] = (byte) (value >> 24 & 0xff);

stream.write(b);

}

protected void writeLong(FileOutputStream stream, long value) throws IOException {

byte[] b = new byte[4];

b[0] = (byte) (value & 0xff);

b[1] = (byte) (value >> 8 & 0xff);

b[2] = (byte) (value >> 16 & 0xff);

b[3] = (byte) (value >> 24 & 0xff);

stream.write(b);

}