////////////////////////////////////////////////////////////////////////////
// PGimage.hh
//
// Paul McCartney, January 1996
//
// Copyright 1996, Washington University Computer Science Department
// All Rights Reserved
//
// RCS:  $Id: PGimage.hh,v 1.4 1996/08/22 19:03:00 paul Exp paul $
//
// This defines the PGimage class.  The purpose of PGimage is to be a wrapper
// to manage the sending and receiving of an image using Playground data 
// structures.  Internally, memory blocks are is used to store the images, 
// since this is the most efficient way to send and receive data.
//
// A pixel value represents an index into a color table, rather than an
// actual color value.  Each pixel of an image is represented as an unsigned 
// char, so the images are restricted to 8-bit color values.
//
// Unlike other Playground data types, I/O is handled explicitly by the
// programmer.  That is, current working data is local and is only sent
// out to external module when the "SendImage" and "SendColorTable" methods
// are invoked.  Similarly, values are only received when the "Receive" 
// method is invoked.  This ensures efficient, atomic operations.
////////////////////////////////////////////////////////////////////////////
#ifndef PGIMAGE_HH
#define PGIMAGE_HH

#include "PG.hh"

class PGimage;


class PGimage : public PGtuple {
public:
  PGimage();
  PGimage(const PGimage& image);
  PGimage& operator=(const PGimage& image);

  // *** FIELDS ***

  PGint id;                      // ID, for use with a series of images
  PGint width, height;           // size of the image
  PGint options;
  PGmemoryBlock pixels;          // pixel data of the image
  PGmemoryBlock colors;          // color table, containing rgb pixel values

  // *** ACCESSORS:  WRITE ***

  void SetSize(int w, int h);
  void SetColorTableSize(int size);
  int ColorTableSize();
  void SetPixel(int x, int y, unsigned char pixel);
  void SetColorEntry(int index, int red, int green, int blue);

  // *** ACCESSORS:  READ  ***

  unsigned char GetPixel(int x, int y);
  void GetColorEntry(int index, int& red, int& green, int& blue);

  // *** Playground I/O ***

  void Send();
};


#endif