// This reads a bma file, averages the three colors of each pixel, and writes a .jpg file.
import java.awt.image.*;
import javax.imageio.ImageIO;
import java.io.*;

class b2j1 {

static int uv(byte b){return (255&(int)b);}

static public void main(String[] args){
  try {
    DataInputStream is = new DataInputStream(new FileInputStream(args[0]));
    int X = is.readInt(), Y = is.readInt();
    System.out.println("X="+X+"Y="+Y);
    BufferedImage I = new BufferedImage(X, Y, BufferedImage.TYPE_BYTE_GRAY);
    WritableRaster wr = I.getRaster();
    byte[] bc = new byte[3*X];
    byte[] bcm = new byte[X];
    for(int i = 0; i<Y; ++i) {is.read(bc);
      for(int j = 0; j<X; ++j)
        bcm[j] = (byte)((uv(bc[3*j]) + uv(bc[3*j+1]) + uv(bc[3*j+2]))/3);
      wr.setDataElements(0, i, X, 1, bcm);}
    try {ImageIO.write(I, "jpg", new File(args[1]));}
    catch (IOException e) {System.err.println("image not saved.");}}
  catch (IOException e) {System.err.println("File not read.");}}}