基于@ ben75提出的以下问题:Android:将位图保存为bmp文件格式
我现在的问题是:如何获得每像素深度为1位(黑白)的BMP图像?
回答我自己的问题...
在网络上进行了艰苦的搜索之后,我意识到我必须创建两件事:黑色和白色的位图-并使用将所有0设置为低于128的颜色并将其余255设置为255的方法来做到这一点,就像这样(这是C#代码,因为我正在使用Xamarin编写我的应用程序):
private void ConvertArgbToOneColor (Bitmap bmpOriginal, int width, int height){
int pixel;
int k = 0;
int B=0,G=0,R=0;
try{
for(int x = 0; x < height; x++) {
for(int y = 0; y < width; y++, k++) {
pixel = bmpOriginal.GetPixel(y, x);
R = Color.GetRedComponent(pixel);
G = Color.GetGreenComponent(pixel);
B = Color.GetBlueComponent(pixel);
R = G = B = (int)(0.299 * R + 0.587 * G + 0.114 * B);
if (R < 128) {
m_imageArray[k] = 0;
} else {
m_imageArray[k] = 1;
}
}
if(m_dataWidth>width){
for(int p=width;p<m_dataWidth;p++,k++){
m_imageArray[k]=1;
}
}
}
}catch (Exception e) {
System.Console.WriteLine ("Converting to grayscale ex: " + e.Message);
}
}
然后获取单色图像的byteArray:
int length = 0;
for (int i = 0; i < m_imageArray.Length; i = i + 8) {
byte first = m_imageArray[i];
for (int j = 0; j < 7; j++) {
byte second = (byte) ((first << 1) | m_imageArray[i + j]);
first = second;
}
m_rawImage[length] = first;
length++;
}
最后,使用以下变量“手动”创建位图,并将其放入FileOutputStream中以保存文件:
private static int FILE_HEADER_SIZE = 14;
private static int INFO_HEADER_SIZE = 40;
// Bitmap file header
private byte[] bfType = { (byte) 'B', (byte) 'M' };
private int bfSize = 0;
private int bfReserved1 = 0;
private int bfReserved2 = 0;
private int bfOffBits = FILE_HEADER_SIZE + INFO_HEADER_SIZE + 8;
// Bitmap info header
private int biSize = INFO_HEADER_SIZE;
private int biWidth = 0;
private int biHeight = 0;
private int biPlanes = 1;
private int biBitCount = 1;
private int biCompression = 0;
private int biSizeImage = 0;
private int biXPelsPerMeter = 0x0;
private int biYPelsPerMeter = 0x0;
private int biClrUsed = 2;
private int biClrImportant = 2;
// Bitmap raw data
private byte[] bitmap;
// Scanlinsize;
int scanLineSize = 0;
// Color Pallette to be used for pixels.
private byte[] colorPalette = { 0, 0, 0, (byte) 255, (byte) 255,
(byte) 255, (byte) 255, (byte) 255 };
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