/**************************************************************************
/* 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.core;

import java.util.*;
import java.awt.*;
import java.awt.geom.*;

/**
   This is the base class for primitive plottable objects, i.e. objects which
   are no composite objects and therefore have their own properties object.

   <p>Since all primitive Plottable objects  have to save the state before
   plotting themselves, a default implementation of
   <em>plot()</em> is provided. The method <em>plot()</em> saves the state,
   then calls <em>plotObjects()</em> and after that restores the previous
   state again. Subclasses of <code>AbstractPlottable</code> therefore
   only have to implement the <em>plotObjects()</em> method and have to
   override the <em>saveState()</em> and <em>restoreState()</em> methods.

   <p>Subclasses should also implement a typesafe <em>setProperties()</em>
   method.

   @version $Revision: 1.3 $
   @author  $Author: bablokb $
*/

public abstract class AbstractPlottable implements Plottable {

  /**
     Properties object.
  */

  protected BasicProperties iProperties = null;

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

  /**
     Color object for save/restore of state.
  */

  private Color iColorState = null;

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

  /**
     Stroke object for save/restore of state.
  */

  protected Stroke iStrokeState = null;

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

  /**
     Set properties object.
  */

  public void setProperties(BasicProperties p) {
    iProperties = p;
  }

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

  /**
     Query properties object.
  */

  public BasicProperties getProperties() {
    return iProperties;
  }

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

  /**
     Save current stroke.
  */

  private void saveStroke(Graphics2D g2) {
    int width = iProperties.getWidth();                 // iProperties != null
    int dashType = iProperties.getDashType();
    if (width != 0 || dashType != Plotlib.SOLID) {
      iStrokeState = g2.getStroke();
      if (dashType != Plotlib.SOLID)
	g2.setStroke(new BasicStroke(width,BasicStroke.CAP_BUTT,
                     BasicStroke.JOIN_ROUND,0,Plotlib.DASH_TABLE[dashType],0));
      else
	g2.setStroke(new BasicStroke(width));
    }
  }

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

  /**
     Save the current state. Subclasses might override this method
     and then call super.saveState().
  */

  public void saveState(Graphics2D g2) {
    if (iProperties != null) {
      Color color = iProperties.getColor();
      if (color != null) {
	iColorState = g2.getColor();
	g2.setColor(color);
      }
      saveStroke(g2);
    }
  }

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

  /**
     Restore the old state. Subclasses might override this method
     and then call super.restoreState().
  */

  public void restoreState(Graphics2D g2) {
    if (iColorState != null)
      g2.setColor(iColorState);
    if (iStrokeState != null)
      g2.setStroke(iStrokeState);
  }

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

  /**
     Handle attributes and call plotObjects().
  */

  public void plot(PlottingContext pc) {
    Graphics2D g2 = pc.getG2();
    if (iProperties != null)
      saveState(g2);
    plotObjects(pc);
    if (iProperties != null)
      restoreState(g2);
  }

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

  /**
     Plot current object. Must be overridden by subclasses.
  */

  public abstract void plotObjects(PlottingContext pc);
}