cgal/Qt_widget/include/CGAL/IO/Qt_widget_get_circle.h

// Copyright (c) 2002-2004  INRIA Sophia-Antipolis (France).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; either version 3 of the License,
// or (at your option) any later version.
//
// Licensees holding a valid commercial license may use this file in
// accordance with the commercial license agreement provided with the software.
//
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
//
// $URL$
// $Id$
// 
//
// Author(s)     : Radu Ursu

#ifndef CGAL_QT_WIDGET_GET_CIRCLE_H
#define CGAL_QT_WIDGET_GET_CIRCLE_H

#include <CGAL/IO/Qt_widget.h>
#include <CGAL/IO/Qt_widget_layer.h>
#include <CGAL/squared_distance_2.h> 

#ifndef CGAL_QT_WIDGET_GET_POINT_BUTTON
#define CGAL_QT_WIDGET_GET_POINT_BUTTON Qt::LeftButton
#endif


namespace CGAL {

template <class R>
class Qt_widget_get_circle : public Qt_widget_layer
{
public:
  typedef typename R::Point_2   Point;
  typedef typename R::Circle_2  Circle;
  typedef typename R::FT        FT;

  Qt_widget_get_circle(const QCursor c=QCursor(Qt::crossCursor),
		       QObject* parent = 0, const char* name = 0)
     : Qt_widget_layer(parent, name), cursor(c), firstpoint(false),
       firsttime(true){};

  void draw(){
    firsttime = true;
  }

protected:
  bool is_pure(Qt::ButtonState s){
    if((s & Qt::ControlButton) ||
       (s & Qt::ShiftButton) ||
       (s & Qt::AltButton))
      return 0;
    else
      return 1;
  }

  void mousePressEvent(QMouseEvent *e)
  {
    if(e->button() == CGAL_QT_WIDGET_GET_POINT_BUTTON 
       && !firstpoint
       && is_pure(e->state()))
    {
      FT x, y;
      widget->x_real(e->x(), x);
      widget->y_real(e->y(), y);
      x1 = x;
      y1 = y;
      x2 = x;
      y2 = y;
      firstpoint = true;
    } else if(e->button() == CGAL_QT_WIDGET_GET_POINT_BUTTON){
      FT x, y; 
      widget->x_real(e->x(), x);
      widget->y_real(e->y(), y);
      widget->new_object(make_object(Circle(Point(x1,y1),
	      squared_distance(Point(x1, y1), Point(x,y)))));
      firstpoint = false;
      firsttime = true;
    }
  };

  void keyPressEvent(QKeyEvent *e)
  {
    switch ( e->key() ) {
      case Key_Escape:			// key_escape
         if(firstpoint)
         {
           firstpoint = false;
           RasterOp old_raster = widget->rasterOp();
           QColor old_color = widget->color();
           widget->lock();
           widget->setRasterOp(XorROP);
           *widget << CGAL::GREEN;
           *widget << Circle(Point(x1,y1),
                      squared_distance(Point(x1, y1), Point(x2,y2)));
           widget->setRasterOp(old_raster);
           widget->setColor(old_color);
           widget->unlock();
           firsttime = true;
         }
         break;
    }//endswitch
  }

  void leaveEvent(QEvent *)
  {
    if(firstpoint)
    {
      QColor old_color = widget->color();
      RasterOp old_raster = widget->rasterOp();//save the initial raster mode
      
      widget->lock();
        widget->setRasterOp(XorROP);
        *widget << CGAL::GREEN;
        *widget << Circle(Point(x1,y1),
        squared_distance(Point(x1, y1), Point(x2,y2)));
      widget->unlock();
      widget->setRasterOp(old_raster);
      widget->setColor(old_color);
      firsttime = true;
    }
  }

  void mouseMoveEvent(QMouseEvent *e)
  {
    if(firstpoint==TRUE)
    {		
      FT x, y;
      widget->x_real(e->x(), x);
      widget->y_real(e->y(), y);
      QColor old_color = widget->color();
      RasterOp old_raster = widget->rasterOp();//save the initial raster mode		
      widget->setRasterOp(XorROP);
      widget->lock();
      *widget << CGAL::GREEN;
      if(!firsttime)
        *widget << Circle(Point(x1,y1),
		  squared_distance(Point(x1, y1), Point(x2,y2)));
      *widget << Circle(Point(x1,y1),
		  squared_distance(Point(x1, y1), Point(x,y)));
      widget->unlock();
      widget->setRasterOp(old_raster);
      widget->setColor(old_color);

      //save the last coordinates to redraw the screen
      x2 = x;
      y2 = y;	
      firsttime = false;
    }
  };
  void activating()
  {
    oldpolicy = widget->focusPolicy();
    widget->setFocusPolicy(QWidget::StrongFocus);
    oldcursor = widget->cursor();
    widget->setCursor(cursor);
  };
  
  void deactivating()
  {
    widget->setFocusPolicy(oldpolicy);
    widget->setCursor(oldcursor);
    firstpoint = false;
  };

  QCursor cursor;
  QCursor oldcursor;
  

  FT    x1, //the X of the first point
        y1; //the Y of the first point
  FT    x2, //the old second point's X
        y2; //the old second point's Y
  bool	firstpoint, //true if the user left clicked once
	firsttime;  //true if the line is not drawn
  QWidget::FocusPolicy	oldpolicy;
};//end class 

} // namespace CGAL

#endif // CGAL_QT_WIDGET_GET_SEGMENT_H