//
//  Filename         : StrokeShader.h
//  Author(s)        : Stephane Grabli, Emmanuel Turquin
//  Purpose          : Class defining StrokeShader
//  Date of creation : 01/07/2003
//
///////////////////////////////////////////////////////////////////////////////


//
//  Copyright (C) : Please refer to the COPYRIGHT file distributed 
//   with this source distribution. 
//
//  This program is free software; you can redistribute it and/or
//  modify it under the terms of the GNU General Public License
//  as published by the Free Software Foundation; either version 2
//  of the License, or (at your option) any later version.
//
//  This program is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with this program; if not, write to the Free Software
//  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
//
///////////////////////////////////////////////////////////////////////////////

#ifndef  SHADERS_H
# define SHADERS_H

# include <iostream>
# include <vector>

//
//  StrokeShader base class
//
//////////////////////////////////////////////////////

class Stroke;
/*! Base class for Stroke Shaders.
 *  Any Stroke Shader must inherit from
 *  this class and overload the shade() method.
 *  A StrokeShader is designed to modify any
 *  Stroke's attribute such as Thickness, Color,
 *  Geometry, Texture, Blending mode...
 *  The basic way to achieve this operation consists
 *  in iterating over the StrokeVertices of the Stroke
 *  and to modify each one's StrokeAttribute.
 *  Here is a python code example of such an iteration:
 *  \code
 *  it = ioStroke.strokeVerticesBegin()
 *  while it.isEnd() == 0:
 *      att = it.getObject().attribute()
 *      ## perform here any attribute modification
 *      it.increment()
 *  \endcode
 *  Here is a C++ code example of such an iteration:
 *  \code
 *  for(StrokeInternal::StrokeVertexIterator v=ioStroke.strokeVerticesBegin(), vend=ioStroke.strokeVerticesEnd();
 *	v!=vend;
 *	++v){
 *    StrokeAttribute& att = v->attribute();
 *    // perform any attribute modification here...
 *  }
 *  \endcode
 */
class LIB_STROKE_EXPORT StrokeShader
{
public:
  /*! Default constructor. */
  StrokeShader() {}
  /*! Destructor. */
  virtual ~StrokeShader() {}
  /*! Returns the string corresponding to the
   *  shader's name.
   */
  virtual string getName() const {
    return "StrokeShader";
  }
  /*! The shading method. This method must
   *  be overloaded by inherited classes.
   *  The shading method is designed to modify any
   *  Stroke's attribute such as Thickness, Color,
   *  Geometry, Texture, Blending mode...
   *  The basic way to achieve this operation consists
   *  in iterating over the StrokeVertices of the Stroke
   *  and to modify each one's StrokeAttribute.
   *  Here is a python code example of such an iteration:
   *  \code
   *  it = ioStroke.strokeVerticesBegin()
   *  while it.isEnd() == 0:
   *      att = it.getObject().attribute()
   *      ## perform here any attribute modification
   *      it.increment()
   *  \endcode
   *  Here is a C++ code example of such an iteration:
   *  \code
   *  for(StrokeInternal::StrokeVertexIterator v=ioStroke.strokeVerticesBegin(), vend=ioStroke.strokeVerticesEnd();
   *	v!=vend;
   *	++v){
   *    StrokeAttribute& att = v->attribute();
   *    // perform any attribute modification here...
   *  }
   *  \endcode
   *  \param ioStroke
   *    The stroke we wish to shade. this Stroke
   *    is modified by the Shader (which typically
   *    modifies the Stroke's attribute's values such
   *    as Color, Thickness, Geometry...)
   */
  virtual void shade(Stroke& ioStroke) const {
    cerr << "Warning: method shade() not implemented" << endl;
  }

};

# endif // SHADERS_H