#ifndef IPGRADIENT_HEADER
#define IPGRADIENT_HEADER 1
////////////////////////////////////////////////////////////////////////////
//! lib=IPLinear
//! docentry="Image.Image Processing.Spatial_Filters"
//! file="amma/Image/IPStream/IPLinear/IPGradient.hh"
//! rcsid="$Id: IPGradient.hh,v 1.3 2000/07/07 12:57:54 ees1cg Exp $"
//! author="Bill Christmas"
//! date="02/12/99"

#include "amma/DP/Process.hh"
#include "amma/NumImage.hh"
#include "amma/Image/IPSpatDiff.hh"
#include "amma/Vector2d.hh"

using namespace IPSpatFilterN;

//! userlevel=Develop
//: Body class for spatial gradient filter
//
// Estimates horizontal and vertical spatial derivatives, using central
// differences of order 1..3.  You should not use this class directly, but
// rather the handle class IPGradientC.
//

class IPGradientBodyC
  : public DPProcessBodyC<NumImageC<RealT>,NumImageC<Vector2dC> >, private IPSpatFilterC
{

public:
  IPGradientBodyC (UIntT Order, ResizeT Resize, PadT Pad);
  //: Constructor
  // (See handle class IPGradientC)

  virtual NumImageC<Vector2dC> Apply (const NumImageC<RealT> &im);
  //: For each pixel im image "im", computes horizontal and vertical
  // differences.

};


//! userlevel=Normal
//: Spatial gradient filter
//
// Estimates horizontal and vertical spatial derivatives, using central
// differences of order 1..3. 
//
// <p>See namespace IPSpatFilterN (or IPSpatFilterC for now) for parameter
// typedefs.

class IPGradientC
  : public DPProcessC<NumImageC<RealT>,NumImageC<Vector2dC> >
{

public:
  IPGradientC();
  //: Default constructor.
  // Creates an invalid handle.
  
  IPGradientC (UIntT Order, ResizeT Resize = Erode, PadT Pad = PadBlack);
  //: Constructor with mask size and optional border processing and shifting
  //
  //!param: Order - difference order: implemented for values in range 1..3 
  //!param: Resize - o/p image size w.r.t i/p image:  Erode, Original, Expand
  //!param: Pad - pad extended image: PadBlack, Repeat, Reflect
  //!param: Shift - if mask size is even, o/p is 1/2 pixel offset w.r.t. i/p, so 1/2 pixel shift is either: ShiftUL, ShiftDR
  //
  // <p>Notes: <ul>
  //
  // <li><code>Erode</code> option means that no special border processing is
  // needed.
  //
  // </ul>
};


#endif