/*

Copyright(C) 1998 Tom Whittaker.

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 1, 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 General Public License in file NOTICE for more details.
 
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/


import java.awt.*;
import java.applet.*;
import java.util.*;
import java.lang.*;
import java.awt.image.*;

/** create an image with designated level transparent
 *
 * @author Tom Whittaker, SSEC
 *
 */

public class TransparentImage extends RGBImageFilter {
  Image imgShow,ti;
  private FilteredImageSource fis;
  private int transparent;
  private int tRedBottom, tRedTop;
  private int tGreenBottom, tGreenTop;
  private int tBlueBottom, tBlueTop;
  private int transAmount;

  private boolean single;
  int count = 0;


  /** create transparent image
   *
   * @param parent is the applet invoking this
   * @param source is the source image 
   * @param ta is percent of opacity (0=transparent, 100=opaque)
   * @param trans is the color trans (rgb) to use as "transparent"
   *
   */
  public TransparentImage(Component parent,Image source, int ta, int trans) {

    single = true;
    setUpImage(parent, source, ta, trans);

  }

  private void setUpImage(Component parent, Image source, int ta, int trans) {

    canFilterIndexColorModel = true;
    transparent = trans;

    if (ta < 0) ta = 0;
    if (ta > 100) ta = 100;
    transAmount = (((255*ta)/100 & 0xff) << 24);  // convert 0-255

    fis = new FilteredImageSource(source.getSource(), this) ;
    ti = parent.createImage(fis);
    MediaTracker track = new MediaTracker(parent);
    track.addImage(ti,0);
    try {track.waitForID(0); }
    catch (Exception e) {;}

  }

  public TransparentImage(Applet parent,Image source, int ta, int transBottom,
    int transTop) {

    // if bottom == top, use more efficient mode...

    if (! (transBottom == transTop) ) {
      // otherwise, use a range for each component
      single = false;
      tRedBottom = (transBottom & 0x00ff0000);
      tRedTop =       (transTop & 0x00ff0000);
      tGreenBottom = (transBottom & 0x0000ff00);
      tGreenTop =       (transTop & 0x0000ff00);
      tBlueBottom = (transBottom & 0x000000ff);
      tBlueTop =       (transTop & 0x000000ff);
    } else {
      single = true;
    }

    setUpImage(parent, source, ta, transBottom);

  }

  /** return the transparent image
   *
   * @return imgShow is the Image
   *
   */
  public Image getImage() {
    return ti;
  }

  public int filterRGB(int x, int y, int rgb) {

    if (single) {
      if ( (rgb & 0x00ffffff) == transparent) 
            return (rgb & 0x00ffffff);
    } else {
      if ( (rgb & 0x00ff0000) >= tRedBottom &&
           (rgb & 0x00ff0000) <= tRedTop &&
           (rgb & 0x0000ff00) >= tGreenBottom &&
           (rgb & 0x0000ff00) <= tGreenTop &&
           (rgb & 0x000000ff) >= tBlueBottom &&
           (rgb & 0x000000ff) <= tBlueTop)
              return (rgb & 0x00ffffff) ;
    }

    return ((rgb & 0x00ffffff) | transAmount);
  }
}