visibilitypolicy.h

Go to the documentation of this file.

//--- < VISIBILITYPOLICY.H > ----| ViewGraph - A Flexible Graph view Framework |
//
// This file contains the default visibility policy for
// a graph's nodes. Include this file and derive from
// DefaultVisibilityPolicy in order to control when certain
// objects appear and how big they are at certain zoom 
// levels.

// For details, see the comments further down.
//
// $Author: botik32 $
// $Revision: 1.1.1.1 $
// $Date: 2004/03/26 10:50:26 $
//-----------------------------------------------------------------------------/


#ifndef VISIBILITYPOLICY_H
#define VISIBILITYPOLICY_H

/// This is a behaviour class for GraphDisplay.
/// Its sole purpose is to decide on what level
/// of magnification the object should appear.
class DefaultVisibilityPolicy
{
public:
        /// returns the level of magnification at 
        /// which the node appears in normal size.
        /// Returned value cannot be less than 1.
        virtual double magnification_level( void * )
        {
                // default behaviour: all nodes get drawn
                return 1;
        };
};

// You can define your behaviour class that knows your
// node more intimately, like this:
/*

class MyVisibilityPolicy : public DefaultVisibilityPolicy
{
public:
        /// This function checks a MyNode for the
        /// weight and uses it to define the magni
        /// fication level
        double magnification_level( void *node )
        {
                MyNode *mynode = (MyNode*)node;
                double lvl = MAX_WGT/sqrt(mynode->get_weight());
                return lvl>1 ? lvl : 1;
        };
};


*/

#endif

/// $Log: visibilitypolicy.h,v $
/// Revision 1.1.1.1  2004/03/26 10:50:26  botik32
/// Initial release
///
/// Revision 1.1.1.1  2004/03/26 08:53:33  botik
/// initial import
///
///
/// Revision 1.2  2003/10/13 16:42:08  botik
/// Added the Log keyword to the end of file
///

---