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			524 lines
		
	
	
		
			19 KiB
		
	
	
	
		
			Java
		
	
	
	
			
		
		
	
	
			524 lines
		
	
	
		
			19 KiB
		
	
	
	
		
			Java
		
	
	
	
| /* SizeRequirements.java --
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|    Copyright (C) 2002, 2005 Free Software Foundation, Inc.
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| 
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| This file is part of GNU Classpath.
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| 
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| GNU Classpath is free software; you can redistribute it and/or modify
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| it under the terms of the GNU General Public License as published by
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| the Free Software Foundation; either version 2, or (at your option)
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| any later version.
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| 
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| GNU Classpath is distributed in the hope that it will be useful, but
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| WITHOUT ANY WARRANTY; without even the implied warranty of
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| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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| General Public License for more details.
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| 
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| You should have received a copy of the GNU General Public License
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| along with GNU Classpath; see the file COPYING.  If not, write to the
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| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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| 02110-1301 USA.
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| 
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| Linking this library statically or dynamically with other modules is
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| making a combined work based on this library.  Thus, the terms and
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| conditions of the GNU General Public License cover the whole
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| combination.
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| 
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| As a special exception, the copyright holders of this library give you
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| permission to link this library with independent modules to produce an
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| executable, regardless of the license terms of these independent
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| modules, and to copy and distribute the resulting executable under
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| terms of your choice, provided that you also meet, for each linked
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| independent module, the terms and conditions of the license of that
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| module.  An independent module is a module which is not derived from
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| or based on this library.  If you modify this library, you may extend
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| this exception to your version of the library, but you are not
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| obligated to do so.  If you do not wish to do so, delete this
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| exception statement from your version. */
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| 
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| package javax.swing;
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| 
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| import java.io.Serializable;
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| 
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| /**
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|  * This class calculates information about the size and position requirements
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|  * of components.
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|  *
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|  * Two types of layout are supported:
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|  * <ul>
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|  * <li>Tiled: the components are placed at position top-left or bottom-right
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|  *    position within their allocated space</li>
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|  * <li>Aligned: the components are placed aligned in their allocated space
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|  *    according to their alignment value</li>
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|  * </ul>
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|  *
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|  * @author Andrew Selkirk
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|  * @author Roman Kennke (roman@kennke.org)
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|  */
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| public class SizeRequirements implements Serializable
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| {
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|   /**
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|    * The serialVersionUID.
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|    */
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|   private static final long serialVersionUID = 9217749429906736553L;
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| 
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|   /**
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|    * The minimum reasonable width or height of a component.
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|    */
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|   public int minimum;
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| 
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|   /**
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|    * The preferred width or height of a component.
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|    */
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|   public int preferred;
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| 
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|   /**
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|    * The maximum reasonable width or height of a component.
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|    */
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|   public int maximum;
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| 
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|   /**
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|    * The horizontal or vertical alignment of a component.
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|    */
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|   public float alignment;
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| 
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|   /**
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|    * Creates a SizeRequirements object with minimum, preferred and
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|    * maximum size set to zero, and an alignment value of 0.5.
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|    */
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|   public SizeRequirements()
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|   {
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|     this (0, 0, 0, 0.5F);
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|   }
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| 
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|   /**
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|    * Creates a SizeRequirements object with the specified minimum,
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|    * preferred, maximum and alignment values.
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|    *
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|    * @param min the minimum reasonable size of the component
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|    * @param pref the preferred size of the component
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|    * @param max the maximum size of the component
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|    * @param align the alignment of the component
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|    */
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|   public SizeRequirements(int min, int pref, int max, float align)
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|   {
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|     minimum = min;
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|     preferred = pref;
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|     maximum = max;
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|     alignment = align;
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|   }
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| 
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|   /**
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|    * Returns a String representation of this SizeRequirements object,
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|    * containing information about the minimum, preferred, maximum and
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|    * alignment value.
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|    *
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|    * @return a String representation of this SizeRequirements object
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|    */
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|   public String toString()
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|   {
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|     StringBuilder b = new StringBuilder();
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|     b.append("<[");
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|     b.append(minimum);
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|     b.append(',');
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|     b.append(preferred);
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|     b.append(',');
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|     b.append(maximum);
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|     b.append("]@");
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|     b.append(alignment);
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|     b.append('>');
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|     return b.toString();
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|   }
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| 
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|   /**
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|    * Calculates how much space is nessecary to place a set of components
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|    * end-to-end. The size requirements of the components is specified
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|    * in <code>children</code>.
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|    *
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|    * @param children the SizeRequirements of each of the components
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|    *
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|    * @return the SizeRequirements that describe how much space is needed
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|    *     to place the components end-to-end
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|    */
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|   public static SizeRequirements
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|   getTiledSizeRequirements(SizeRequirements[] children)
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|   {
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|     long minimum = 0;
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|     long preferred = 0;
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|     long maximum = 0;
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|     for (int i = 0; i < children.length; i++)
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|       {
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|         minimum += children[i].minimum;
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|         preferred += children[i].preferred;
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|         maximum += children[i].maximum;
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|       }
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|     // Overflow check.
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|     if (minimum > Integer.MAX_VALUE)
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|       minimum = Integer.MAX_VALUE;
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|     if (preferred > Integer.MAX_VALUE)
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|       preferred = Integer.MAX_VALUE;
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|     if (maximum > Integer.MAX_VALUE)
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|       maximum = Integer.MAX_VALUE;
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|     SizeRequirements result = new SizeRequirements((int) minimum,
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|                                                    (int) preferred,
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|                                                    (int) maximum,
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|                                                    0.5F);
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|     return result;
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|   }
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| 
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|   /**
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|    * Calculates how much space is nessecary to place a set of components
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|    * aligned according to their alignment value.
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|    * The size requirements of the components is specified in
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|    * <code>children</code>.
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|    *
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|    * @param children the SizeRequirements of each of the components
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|    *
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|    * @return the SizeRequirements that describe how much space is needed
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|    *     to place the components aligned
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|    */
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|   public static SizeRequirements
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|   getAlignedSizeRequirements(SizeRequirements[] children)
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|   {
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|     float minLeft = 0;
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|     float minRight = 0;
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|     float prefLeft = 0;
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|     float prefRight = 0;
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|     float maxLeft = 0;
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|     float maxRight = 0;
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|     for (int i = 0; i < children.length; i++)
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|       {
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|         float myMinLeft = children[i].minimum * children[i].alignment;
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|         float myMinRight = children[i].minimum - myMinLeft;
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|         minLeft = Math.max(myMinLeft, minLeft);
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|         minRight = Math.max(myMinRight, minRight);
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|         float myPrefLeft = children[i].preferred * children[i].alignment;
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|         float myPrefRight = children[i].preferred - myPrefLeft;
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|         prefLeft = Math.max(myPrefLeft, prefLeft);
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|         prefRight = Math.max(myPrefRight, prefRight);
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|         float myMaxLeft = children[i].maximum * children[i].alignment;
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|         float myMaxRight = children[i].maximum - myMaxLeft;
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|         maxLeft = Math.max(myMaxLeft, maxLeft);
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|         maxRight = Math.max(myMaxRight, maxRight);
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|       }
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|     int minSize = (int) (minLeft + minRight);
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|     int prefSize = (int) (prefLeft + prefRight);
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|     int maxSize = (int) (maxLeft + maxRight);
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|     float align = prefLeft / (prefRight + prefLeft);
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|     if (Float.isNaN(align))
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|       align = 0;
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|     return new SizeRequirements(minSize, prefSize, maxSize, align);
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|   }
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| 
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|   /**
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|    * Calculate the offsets and spans of the components, when they should
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|    * be placed end-to-end.
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|    *
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|    * You must specify the amount of allocated space in
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|    * <code>allocated</code>, the total size requirements of the set of
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|    * components in <code>total</code> (this can be calculated using
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|    * {@link #getTiledSizeRequirements} and the size requirements of the
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|    * components in <code>children</code>.
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|    *
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|    * The calculated offset and span values for each component are then
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|    * stored in the arrays <code>offsets</code> and <code>spans</code>.
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|    *
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|    * The components are placed in the forward direction, beginning with
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|    * an offset of 0.
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|    *
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|    * @param allocated the amount of allocated space
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|    * @param total the total size requirements of the components
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|    * @param children the size requirement of each component
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|    * @param offsets will hold the offset values for each component
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|    * @param spans will hold the span values for each component
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|    */
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|   public static void calculateTiledPositions(int allocated,
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|                                              SizeRequirements total,
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|                                              SizeRequirements[] children,
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|                                              int[] offsets, int[] spans)
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|   {
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|     calculateTiledPositions(allocated, total, children, offsets, spans, true);
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|   }
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| 
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|   /**
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|    * Calculate the offsets and spans of the components, when they should
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|    * be placed end-to-end.
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|    *
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|    * You must specify the amount of allocated space in
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|    * <code>allocated</code>, the total size requirements of the set of
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|    * components in <code>total</code> (this can be calculated using
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|    * {@link #getTiledSizeRequirements} and the size requirements of the
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|    * components in <code>children</code>.
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|    *
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|    * The calculated offset and span values for each component are then
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|    * stored in the arrays <code>offsets</code> and <code>spans</code>.
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|    *
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|    * Depending on the value of <code>forward</code> the components are
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|    * placed in the forward direction (left-right or top-bottom), where
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|    * the offsets begin with 0, or in the reverse direction
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|    * (right-left or bottom-top).
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|    *
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|    * @param allocated the amount of allocated space
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|    * @param total the total size requirements of the components
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|    * @param children the size requirement of each component
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|    * @param offsets will hold the offset values for each component
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|    * @param spans will hold the span values for each component
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|    * @param forward whether the components should be placed in the forward
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|    *     direction (left-right or top-bottom) or reverse direction
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|    *     (right-left or bottom-top)
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|    */
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|   public static void calculateTiledPositions(int allocated,
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|                                              SizeRequirements total,
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|                                              SizeRequirements[] children,
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|                                              int[] offsets, int[] spans,
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|                                              boolean forward)
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|   {
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|     int span = 0;
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|     if (forward)
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|       {
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|         int offset = 0;
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|         for (int i = 0; i < children.length; i++)
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|           {
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|             offsets[i] = offset;
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|             spans[i] = children[i].preferred;
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|             span += spans[i];
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|             offset += children[i].preferred;
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|           }
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|       }
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|     else
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|       {
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|         int offset = allocated;
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|         for (int i = 0; i < children.length; i++)
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|           {
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|             offset -= children[i].preferred;
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|             offsets[i] = offset;
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|             span += spans[i];
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|             spans[i] = children[i].preferred;
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|           }
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|       }
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|     // Adjust spans so that we exactly fill the allocated region. If
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|     if (span > allocated)
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|       adjustSmaller(allocated, children, spans, span);
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|     else if (span < allocated)
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|       adjustGreater(allocated, children, spans, span);
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| 
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|     // Adjust offsets.
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|     if (forward)
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|       {
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|         int offset = 0;
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|         for (int i = 0; i < children.length; i++)
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|           {
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|             offsets[i] = offset;
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|             offset += spans[i];
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|           }
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|       }
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|     else
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|       {
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|         int offset = allocated;
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|         for (int i = 0; i < children.length; i++)
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|           {
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|             offset -= spans[i];
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|             offsets[i] = offset;
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|           }
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|       }
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|   }
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| 
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|   private static void adjustSmaller(int allocated, SizeRequirements[] children,
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|                                     int[] spans, int span)
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|   {
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|     // Sum up (prefSize - minSize) over all children
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|     int sumDelta = 0;
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|     for (int i = 0; i < children.length; i++)
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|       sumDelta += children[i].preferred - children[i].minimum;
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| 
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|     // If we have sumDelta == 0, then all components have prefSize == maxSize
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|     // and we can't do anything about it.
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|     if (sumDelta == 0)
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|       return;
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| 
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|     // Adjust all sizes according to their preferred and minimum sizes.
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|     for (int i = 0; i < children.length; i++)
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|       {
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|         double factor = ((double) (children[i].preferred - children[i].minimum))
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|                         / ((double) sumDelta);
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|         // In case we have a sumDelta of 0, the factor should also be 0.
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|         if (Double.isNaN(factor))
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|           factor = 0;
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|         spans[i] -= factor * (span - allocated);
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|       }
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|   }
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| 
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|   private static void adjustGreater(int allocated, SizeRequirements[] children,
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|                                     int[] spans, int span)
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|   {
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|     // Sum up (maxSize - prefSize) over all children
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|     long sumDelta = 0;
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|     for (int i = 0; i < children.length; i++)
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|       {
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|         sumDelta += children[i].maximum - children[i].preferred;
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|       }
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| 
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|     // If we have sumDelta == 0, then all components have prefSize == maxSize
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|     // and we can't do anything about it.
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|     if (sumDelta == 0)
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|       return;
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| 
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|     // Adjust all sizes according to their preferred and minimum sizes.
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|     for (int i = 0; i < children.length; i++)
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|       {
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|         double factor = ((double) (children[i].maximum - children[i].preferred))
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|                         / ((double) sumDelta);
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|         spans[i] += factor * (allocated - span);
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|       }
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|   }
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| 
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|   /**
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|    * Calculate the offsets and spans of the components, when they should
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|    * be placed end-to-end.
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|    *
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|    * You must specify the amount of allocated space in
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|    * <code>allocated</code>, the total size requirements of the set of
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|    * components in <code>total</code> (this can be calculated using
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|    * {@link #getTiledSizeRequirements} and the size requirements of the
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|    * components in <code>children</code>.
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|    *
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|    * The calculated offset and span values for each component are then
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|    * stored in the arrays <code>offsets</code> and <code>spans</code>.
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|    *
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|    * The components are tiled in the forward direction, beginning with
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|    * an offset of 0.
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|    *
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|    * @param allocated the amount of allocated space
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|    * @param total the total size requirements of the components
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|    * @param children the size requirement of each component
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|    * @param offsets will hold the offset values for each component
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|    * @param spans will hold the span values for each component
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|    */
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|   public static void calculateAlignedPositions(int allocated,
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|                                                SizeRequirements total,
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|                                                SizeRequirements[] children,
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|                                                int[] offsets, int[] spans)
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|   {
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|     calculateAlignedPositions(allocated, total, children, offsets, spans,
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|                               true);
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|   }
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| 
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|   /**
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|    * Calculate the offsets and spans of the components, when they should
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|    * be placed end-to-end.
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|    *
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|    * You must specify the amount of allocated space in
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|    * <code>allocated</code>, the total size requirements of the set of
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|    * components in <code>total</code> (this can be calculated using
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|    * {@link #getTiledSizeRequirements} and the size requirements of the
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|    * components in <code>children</code>.
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|    *
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|    * The calculated offset and span values for each component are then
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|    * stored in the arrays <code>offsets</code> and <code>spans</code>.
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|    *
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|    * Depending on the value of <code>forward</code> the components are
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|    * placed in the forward direction (left-right or top-bottom), where
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|    * the offsets begin with 0, or in the reverse direction
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|    * (right-left or bottom-top).
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|    *
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|    * @param allocated the amount of allocated space
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|    * @param total the total size requirements of the components
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|    * @param children the size requirement of each component
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|    * @param spans will hold the span values for each component
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|    * @param forward whether the components should be placed in the forward
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|    *     direction (left-right or top-bottom) or reverse direction
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|    *     (right-left or bottom-top)
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|    */
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|   public static void calculateAlignedPositions(int allocated,
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|                                                SizeRequirements total,
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|                                                SizeRequirements[] children,
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|                                                int[] offset, int[] spans,
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|                                                boolean forward)
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|   {
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|     // First we compute the position of the baseline.
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|     float baseline = allocated * total.alignment;
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| 
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|     // Now we can layout the components along the baseline.
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|     for (int i = 0; i < children.length; i++)
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|       {
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|         float align = children[i].alignment;
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|         // Try to fit the component into the available space.
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|         int[] spanAndOffset = new int[2];
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|         if (align < .5F || baseline == 0)
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|           adjustFromRight(children[i], baseline, allocated, spanAndOffset);
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|         else
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|           adjustFromLeft(children[i], baseline, allocated, spanAndOffset);
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|         spans[i] = spanAndOffset[0];
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|         offset[i] = spanAndOffset[1];
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|       }
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|   }
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| 
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|   /**
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|    * Adjusts the span and offset of a component for the aligned layout.
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|    *
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|    * @param reqs
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|    * @param baseline
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|    * @param allocated
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|    * @param spanAndOffset
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|    */
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|   private static void adjustFromRight(SizeRequirements reqs, float baseline,
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|                                       int allocated, int[] spanAndOffset)
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|   {
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|     float right = allocated - baseline;
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|     // If the resulting span exceeds the maximum of the component, then adjust
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|     // accordingly.
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|     float maxRight = ((float) reqs.maximum) * (1.F - reqs.alignment);
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|     if (right / (1.F - reqs.alignment) > reqs.maximum)
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|       right = maxRight;
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|     // If we have not enough space on the left side, then adjust accordingly.
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|     if (right / (1.F - reqs.alignment) * reqs.alignment > allocated - baseline)
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|       right = ((float) (allocated - baseline))
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|              / reqs.alignment * (1.F - reqs.alignment);
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| 
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|     spanAndOffset[0] = (int) (right / (1.F - reqs.alignment));
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|     spanAndOffset[1] = (int) (baseline - spanAndOffset[0] * reqs.alignment);
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|   }
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| 
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|   /**
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|    * Adjusts the span and offset of a component for the aligned layout.
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|    *
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|    * @param reqs
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|    * @param baseline
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|    * @param allocated
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|    * @param spanAndOffset
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|    */
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|   private static void adjustFromLeft(SizeRequirements reqs, float baseline,
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|                                      int allocated, int[] spanAndOffset)
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|   {
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|     float left = baseline;
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|     // If the resulting span exceeds the maximum of the component, then adjust
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|     // accordingly.
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|     float maxLeft = ((float) reqs.maximum) * reqs.alignment;
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|     if (left / reqs.alignment > reqs.maximum)
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|       left = maxLeft;
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|     // If we have not enough space on the right side, then adjust accordingly.
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|     if (left / reqs.alignment * (1.F - reqs.alignment) > allocated - baseline)
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|       left = ((float) (allocated - baseline))
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|              / (1.F - reqs.alignment) * reqs.alignment;
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| 
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|     spanAndOffset[0] = (int) (left / reqs.alignment);
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|     spanAndOffset[1] = (int) (baseline - spanAndOffset[0] * reqs.alignment);
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|   }
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| 
 | |
|   /**
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|    * Returns an array of new preferred sizes for the children based on
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|    * <code>delta</code>. <code>delta</code> specifies a change in the
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|    * allocated space. The sizes of the children will be shortened or
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|    * lengthened to accomodate the new allocation.
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|    *
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|    * @param delta the change of the size of the total allocation for
 | |
|    *     the components
 | |
|    * @param children the size requirements of each component
 | |
|    *
 | |
|    * @return the new preferred sizes for each component
 | |
|    */
 | |
|   public static int[] adjustSizes(int delta, SizeRequirements[] children)
 | |
|   {
 | |
|     return null; // TODO
 | |
|   }
 | |
| }
 |