Pixmap.java

import java.io.*;





public class Pixmap {

  private static String MAGIC_PGM = "P5\n";

  private final int width;
  private final int height;
  private final int size;
 
  private byte[] data;	
	


  public Pixmap(int w, int h) {
    width = w;
    height = h;
    size = width * height;
  }

  Pixmap(String fileName, String magic) throws IOException {
    PixmapReader reader = new PixmapReader(fileName);
    if ( !reader.matchKey(magic) )
      throw new IOException(fileName + " : wrong magic number");
    reader.skipComment('#');
    width = reader.getInt();
    height = reader.getInt();
    size = width * height;
    reader.skipLine();
    reader.skipComment('#');
    reader.skipLine();

    data = reader.loadData(size);
    reader.close();
  }


  public Pixmap(String fileName) throws IOException {
    this(fileName, MAGIC_PGM);
  }


  public int getW(){
	return width;
	}

  public int getH(){
	return height;
	}


  final void write(String fileName, String magic, byte[] buffer) {
    try {
      PixmapWriter writer = new PixmapWriter(fileName);
      writer.put(magic);
      writer.put("#\n");
      writer.put(width + " " + height + "\n255\n");
      writer.write(buffer);
      writer.close();
      System.err.println("'" + fileName + "' wrote");
    } catch (IOException e) {
      System.err.println("can't write '"+fileName+"'");
    }
  }
/*
 public abstract byte[] getBytes();
*/
  public void write(String fileName) {
    write(fileName, MAGIC_PGM, data);
  }

  

  public static int intValue(byte b) {
    if ( b < 0 )
      return b + 256;
    else
      return b;
  }

  public static byte byteValue(int v) {
	//0 <= v <= 255
    if ( v > 128 )
      return (byte)(v - 256);
    else
      return (byte)v;
  }

    public int get(int i, int j){
	//retourne entier entre 0 (blanc) et 255 (noir)
	return intValue(data[j*getW()+i]);
    }


    public void set(int i, int j, int v){
	assert((v>=0) && (v <=255));//retourne entier entre 0 (blanc) et 255 (noir)
	data[j*getW()+i]=byteValue(v);
    }

  public void setData(){
    data = new byte[size];
  }

}