// -*- C++ -*- //

#ifndef GRAPH_DISPLAYER_CANVAS_H
#define GRAPH_DISPLAYER_CANVAS_H

#include <all_include.h>
#include <mapstorage.h>
#include <libgnomecanvasmm.h>
#include <libgnomecanvasmm/polygon.h>

///This class is the canvas, on which the graph can be drawn.
class GraphDisplayerCanvas : public Gnome::Canvas::CanvasAA
{
  typedef Gnome::Canvas::CanvasAA Parent;

public:
  GraphDisplayerCanvas(Graph &, CoordinatesMap &, MapStorage &);
  virtual ~GraphDisplayerCanvas();

  ///Changes the linewidth attribute according to the given map.
  ///\param mapname is the name of the map which contains the new values
  int changeLineWidth (std::string mapname);

  ///Changes the linecolor attribute according to the given map.
  ///\param mapname is the name of the map which contains the new values
  int changeColor (std::string mapname);

  ///Changes the text of line attribute according to the given map.
  ///\param mapname is the name of the map which contains the new values
  int changeText (std::string mapname);

  ///Callback for 'ViewZoomIn' action.
  virtual void zoomIn();
  ///Callback for 'ViewZoomOut' action.
  virtual void zoomOut();
  ///Callback for 'ViewZoomFit' action.
  virtual void zoomFit();
  ///Callback for 'ViewZoom100' action.
  virtual void zoom100();
  ///Sets the scroll region of the convas to the bounding box of the graph.
  void updateScrollRegion();

protected:

  //maximizing, minimizing, restoring window, etc. 
  virtual bool on_expose_event(GdkEventExpose *);

private:

  ///This function is responsible for the correct
  ///reaction of any action happened in the territory
  ///of the canvas
  bool event_handler(GdkEvent* e, Node n);

  ///The graph, on which we work
  Graph g;

  ///Map of nodes of graph
  Graph::NodeMap<Gnome::Canvas::Ellipse *> nodesmap;

  ///Map of edges of graph
  Graph::EdgeMap<Gnome::Canvas::Line *> edgesmap;

  ///Map of texts to write on edges
  Graph::EdgeMap<Gnome::Canvas::Text *> edgetextmap;

  ///Group of graphical elements of displayed_graph
  Gnome::Canvas::Group displayed_graph;

  ///Here we store the maps that can be displayed through properties.
  MapStorage mapstorage;

  ///Indicates whether the button of mouse is pressed or not
  bool isbutton;

  ///At this location was the mousebutton pressed.
  ///It helps to calculate the distance of dragging.
  double clicked_x, clicked_y;

  ///Remembers which Gnome::Canvas::Item was pressed.
  ///this variable is needed, because
  ///1. we cannot query the item at he cursor as fast as it could not cause a Segmentation Fault
  ///2. we would like to handle only ony item per movement, therefore quering it is not a working solution
  Gnome::Canvas::Item * active_item;

  static const int zoom_step = 5;
};

#endif //GRAPH_DISPLAYER_CANVAS_H