/**************************************************************************
/* This class is part of the Java Plotlib Toolkit.
/*
/* Copyright (c) 1999-2004 by Bernhard Bablok (bablokb@gmx.de)
/*
/* 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 Library General Public License for more details.
/*
/* You should have received a copy of the GNU General Public License
/* along with this program; see the file COPYING.  If not, write to
/* the Free Software Foundation Inc., 59 Temple Place - Suite 330,
/* Boston, MA  02111-1307 USA
/**************************************************************************/
package de.bablokb.plotlib.plot;

import java.util.*;
import java.awt.*;
import java.awt.geom.*;
import de.bablokb.plotlib.core.*;
import de.bablokb.plotlib.data.*;

/**
   Plot a function y=f(x) or (x,y)=f(t).

   @version $Revision: 1.4 $
   @author  $Author: bablokb $
*/

public class FunctionPlot extends LinePlot {
  
  /**
     Minimum x (respective t) value. Defaults to minimum value of range.
  */

  private double iMinValue = Double.NaN;

  
  /**
     Maximum x (respective t) value. Defaults to maximum value of range.
  */

  private double iMaxValue = Double.NaN;

  /**
     Interval size to calculate values for. This defaults to the unit
     in device coordinates.
  */

  private double iDelta = Double.NaN;

  /**
     Function object.
  */

  private Yfx iFkt = null;

  //////////////////////////////////////////////////////////////////////////////

  /**
     Construct a FunctionPlot-object from given function, value range and 
     interval size.
  */

  public FunctionPlot(Yfx f, double minVal, double maxVal, double delta) {
    iFkt = f;
    iMinValue = minVal;
    iMaxValue = maxVal;
    iDelta = delta;
  }

  //////////////////////////////////////////////////////////////////////////////

  /**
     Construct a FunctionPlot-object from given function.
  */

  public FunctionPlot(Yfx f) {
    iFkt = f;
  }

  //////////////////////////////////////////////////////////////////////////////

  /**
     Set the range and interval size.
  */

  public void setRange(double minVal, double maxVal, double delta) {
    iMinValue = minVal;
    iMaxValue = maxVal;
    iDelta = delta;
  }

  //////////////////////////////////////////////////////////////////////////////

  /**
     Calculate values in the given range.

     <p><strong>FIXME:</strong> Should we clear iData in case iData != null?
  */

  public void createData(PlottingContext pc) {
    if (iFkt == null)
      throw new NoFunctionException();
    double min=iMinValue, max=iMaxValue, delta=iDelta;
    if (Double.isNaN(iMinValue))
      min = pc.getRange().getMinX();
    if (Double.isNaN(iMaxValue))
      max = pc.getRange().getMaxX();
    if (Double.isNaN(iDelta))
      delta = pc.getXratio();
    
    if (iData == null)
      iData = new Dataset(new ArrayList((int) ((max-min)/delta)));
    for (double x=min+delta;x<=max;x+=delta) {
      Point2D p = iFkt.f(x);
      iData.add(p);
    }
  }

  //////////////////////////////////////////////////////////////////////////////

  /**
     Plot the function. Implements AbstractPlottable.plotObjects.
  */

  public void plotObjects(PlottingContext pc) {
    if (iData == null)
      createData(pc);
    super.plotObjects(pc);
  }

  //////////////////////////////////////////////////////////////////////////////
  //////////////////////////////////////////////////////////////////////////////

  /**
     Interface for functions. The method returning a Point2D given a 
     x-coordinate must be implemented. The same interface can be used to plot
     function of the form (x,y) = f(t), since the interface does not
     enforce that the x-value of the Point2D must be equal to the argument.
  */

  static public interface Yfx {

    /**
       Return a Point2D given a value.
    */

    public Point2D f(double x);
  }
}