content: // ===============================================================================
  // Authors: AFRL/RQQD
  // Organization: Air Force Research Laboratory, Aerospace Systems Directorate, Power and Control Division
  // 
  // Copyright (c) 2017 Government of the United State of America, as represented by
  // the Secretary of the Air Force.  No copyright is claimed in the United States under
  // Title 17, U.S. Code.  All Other Rights Reserved.
  // ===============================================================================
  
  /*
   * GRAL: GRAphing Library for Java(R)
   *
   * (C) Copyright 2009-2013 Erich Seifert <dev[at]erichseifert.de>,
   * Michael Seifert <mseifert[at]error-reports.org>
   *
   * This file is part of GRAL.
   *
   * GRAL is free software: you can redistribute it and/or modify
   * it under the terms of the GNU Lesser General Public License as published by
   * the Free Software Foundation, either version 3 of the License, or
   * (at your option) any later version.
   *
   * GRAL 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 Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public License
   * along with GRAL.  If not, see <http://www.gnu.org/licenses/>.
   */
  package de.erichseifert.gral.graphics;
  
  import java.awt.geom.Point2D;
  import java.awt.geom.Rectangle2D;
  
  import de.erichseifert.gral.util.Insets2D;
  
  
  /**
   * An interface that provides functions to build a group of multiple components
   * of {@link Drawable}. It is also responsible for managing layout of its
   * components using a {@link Layout} and layout constraints for each component.
   */
  public interface Container extends Iterable<Drawable> {
  	/**
  	 * Returns the space that this container must preserve at each of its
  	 * edges.
  	 * @return The insets of this DrawableContainer
  	 */
  	Insets2D getInsets();
  
  	/**
  	 * Sets the space that this container must preserve at each of its
  	 * edges.
  	 * @param insets Insets to be set.
  	 */
  	void setInsets(Insets2D insets);
  
  	/**
  	 * Returns the bounds of this container.
  	 * @return bounds
  	 */
  	Rectangle2D getBounds();
  
  	/**
  	 * Sets the bounds of this container.
  	 * @param bounds Bounds
  	 */
  	void setBounds(Rectangle2D bounds);
  
  	/**
  	 * Returns the layout associated with this container.
  	 * @return Layout manager
  	 */
  	Layout getLayout();
  
  	/**
  	 * Recalculates this container's layout.
  	 */
  	void layout();
  
  	/**
  	 * Sets the layout associated with this container.
  	 * @param layout Layout to be set.
  	 */
  	void setLayout(Layout layout);
  
  	/**
  	 * Adds a new component to this container.
  	 * @param drawable Component
  	 */
  	void add(Drawable drawable);
  
  	/**
  	 * Adds a new component to this container.
  	 * @param drawable Component
  	 * @param constraints Additional information (e.g. for layout)
  	 */
  	void add(Drawable drawable, Object constraints);
  
  	/**
  	 * Returns the component at the specified point. If no component could be
  	 * found {@code null} will be returned.
  	 * @param point Two-dimensional point.
  	 * @return Component at the specified point, or {@code null} if no
  	 *         component could be found.
  	 */
  	Drawable getDrawableAt(Point2D point);
  
  	/**
  	 * Return additional information on component
  	 * @param drawable Component
  	 * @return Information object or {@code null}
  	 */
  	Object getConstraints(Drawable drawable);
  
  	/**
  	 * Removes a component from this container.
  	 * @param drawable Component
  	 */
  	void remove(Drawable drawable);
  
  	/**
  	 * Returns the number of components that are stored in this container.
  	 * @return total number of components
  	 */
  	int size();
  }
  