//
// DualRes.java
//

/*
VisAD system for interactive analysis and visualization of numerical
data.  Copyright (C) 1996 - 2017 Bill Hibbard, Curtis Rueden, Tom
Rink, Dave Glowacki, Steve Emmerson, Tom Whittaker, Don Murray, and
Tommy Jasmin.

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.

This library 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 Library General Public
License along with this library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA
*/

package visad.util;

import java.rmi.RemoteException;
import visad.*;

/**
 * Maintains two representations for a given data reference: one at
 * high (normal) resolution, and one at low (scaled-down) resolution.
 * When greater rendering speed is necessary, programs can utilize the
 * computed low-resolution data. When more detail is required, programs
 * can switch back to the hi-resolution data.
 */
public class DualRes {

  /** Debugging flag. */
  public static boolean DEBUG = false;

  /** High-resolution data reference. */
  protected DataReferenceImpl hi_ref;
  
  /** Low-resolution data reference. */
  protected DataReferenceImpl lo_ref;

  /** Computational cell that scales down high-resolution data. */
  private CellImpl cell;

  /** Scale factor for low-resolution data. */
  private double scale = 0.5;

  /** Rescales a field by the given scale factor. */
  public static FieldImpl rescale(FieldImpl field, double scale)
    throws VisADException, RemoteException
  {
    Set set = field.getDomainSet();
    if (!(set instanceof LinearSet)) return null;
    LinearSet lset = (LinearSet) set;
    int dim = set.getDimension();

    // compute new lengths
    int[] lengths = new int[dim];
    for (int i=0; i 1) this.scale = 1.0 / scale;
    else {
      throw new VisADException(
        "DualRes: scale factor must be greater than 1");
    }
  }

  /**
   * Gets the factor by which the low-resolution representation is
   * scaled down from the high-resolution one.
   */
  public double getResolutionScale() { return 1.0 / scale; }

  /** Gets the DataReference corresponding to the full-resolution data. */
  public DataReferenceImpl getHighResReference() { return hi_ref; }

  /** Gets the DataReference corresponding to the scaled-down data. */
  public DataReferenceImpl getLowResReference() { return lo_ref; }

}