// -*- 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);

   ///Changes the dot-pro-pixel to be able to show the whole graph.

   int rezoom();

 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;

 };

 #endif //GRAPH_DISPLAYER_CANVAS_H