Home » openjdk-7 » javax » swing » [javadoc | source]

    1   /*
    2    * Copyright (c) 1997, 2007, Oracle and/or its affiliates. All rights reserved.
    3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
    4    *
    5    * This code is free software; you can redistribute it and/or modify it
    6    * under the terms of the GNU General Public License version 2 only, as
    7    * published by the Free Software Foundation.  Oracle designates this
    8    * particular file as subject to the "Classpath" exception as provided
    9    * by Oracle in the LICENSE file that accompanied this code.
   10    *
   11    * This code is distributed in the hope that it will be useful, but WITHOUT
   12    * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   13    * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   14    * version 2 for more details (a copy is included in the LICENSE file that
   15    * accompanied this code).
   16    *
   17    * You should have received a copy of the GNU General Public License version
   18    * 2 along with this work; if not, write to the Free Software Foundation,
   19    * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   20    *
   21    * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   22    * or visit www.oracle.com if you need additional information or have any
   23    * questions.
   24    */
   25   package javax.swing;
   26   
   27   
   28   import java.awt;
   29   import java.beans.ConstructorProperties;
   30   import java.io.Serializable;
   31   
   32   /**
   33    * A layout manager to arrange components over the top
   34    * of each other.  The requested size of the container
   35    * will be the largest requested size of the children,
   36    * taking alignment needs into consideration.
   37    *
   38    * The alignment is based upon what is needed to properly
   39    * fit the children in the allocation area.  The children
   40    * will be placed such that their alignment points are all
   41    * on top of each other.
   42    * <p>
   43    * <strong>Warning:</strong>
   44    * Serialized objects of this class will not be compatible with
   45    * future Swing releases. The current serialization support is
   46    * appropriate for short term storage or RMI between applications running
   47    * the same version of Swing.  As of 1.4, support for long term storage
   48    * of all JavaBeans<sup><font size="-2">TM</font></sup>
   49    * has been added to the <code>java.beans</code> package.
   50    * Please see {@link java.beans.XMLEncoder}.
   51    *
   52    * @author   Timothy Prinzing
   53    */
   54   public class OverlayLayout implements LayoutManager2,Serializable {
   55   
   56       /**
   57        * Constructs a layout manager that performs overlay
   58        * arrangement of the children.  The layout manager
   59        * created is dedicated to the given container.
   60        *
   61        * @param target  the container to do layout against
   62        */
   63       @ConstructorProperties({"target"})
   64       public OverlayLayout(Container target) {
   65           this.target = target;
   66       }
   67   
   68       /**
   69        * Returns the container that uses this layout manager.
   70        *
   71        * @return the container that uses this layout manager
   72        *
   73        * @since 1.6
   74        */
   75       public final Container getTarget() {
   76           return this.target;
   77       }
   78   
   79       /**
   80        * Indicates a child has changed its layout related information,
   81        * which causes any cached calculations to be flushed.
   82        *
   83        * @param target the container
   84        */
   85       public void invalidateLayout(Container target) {
   86           checkContainer(target);
   87           xChildren = null;
   88           yChildren = null;
   89           xTotal = null;
   90           yTotal = null;
   91       }
   92   
   93       /**
   94        * Adds the specified component to the layout. Used by
   95        * this class to know when to invalidate layout.
   96        *
   97        * @param name the name of the component
   98        * @param comp the the component to be added
   99        */
  100       public void addLayoutComponent(String name, Component comp) {
  101           invalidateLayout(comp.getParent());
  102       }
  103   
  104       /**
  105        * Removes the specified component from the layout. Used by
  106        * this class to know when to invalidate layout.
  107        *
  108        * @param comp the component to remove
  109        */
  110       public void removeLayoutComponent(Component comp) {
  111           invalidateLayout(comp.getParent());
  112       }
  113   
  114       /**
  115        * Adds the specified component to the layout, using the specified
  116        * constraint object. Used by this class to know when to invalidate
  117        * layout.
  118        *
  119        * @param comp the component to be added
  120        * @param constraints  where/how the component is added to the layout.
  121        */
  122       public void addLayoutComponent(Component comp, Object constraints) {
  123           invalidateLayout(comp.getParent());
  124       }
  125   
  126       /**
  127        * Returns the preferred dimensions for this layout given the components
  128        * in the specified target container.  Recomputes the layout if it
  129        * has been invalidated.  Factors in the current inset setting returned
  130        * by getInsets().
  131        *
  132        * @param target the component which needs to be laid out
  133        * @return a Dimension object containing the preferred dimensions
  134        * @see #minimumLayoutSize
  135        */
  136       public Dimension preferredLayoutSize(Container target) {
  137           checkContainer(target);
  138           checkRequests();
  139   
  140           Dimension size = new Dimension(xTotal.preferred, yTotal.preferred);
  141           Insets insets = target.getInsets();
  142           size.width += insets.left + insets.right;
  143           size.height += insets.top + insets.bottom;
  144           return size;
  145       }
  146   
  147       /**
  148        * Returns the minimum dimensions needed to lay out the components
  149        * contained in the specified target container.  Recomputes the layout
  150        * if it has been invalidated, and factors in the current inset setting.
  151        *
  152        * @param target the component which needs to be laid out
  153        * @return a Dimension object containing the minimum dimensions
  154        * @see #preferredLayoutSize
  155        */
  156       public Dimension minimumLayoutSize(Container target) {
  157           checkContainer(target);
  158           checkRequests();
  159   
  160           Dimension size = new Dimension(xTotal.minimum, yTotal.minimum);
  161           Insets insets = target.getInsets();
  162           size.width += insets.left + insets.right;
  163           size.height += insets.top + insets.bottom;
  164           return size;
  165       }
  166   
  167       /**
  168        * Returns the maximum dimensions needed to lay out the components
  169        * contained in the specified target container.  Recomputes the
  170        * layout if it has been invalidated, and factors in the inset setting
  171        * returned by <code>getInset</code>.
  172        *
  173        * @param target the component that needs to be laid out
  174        * @return a <code>Dimension</code> object containing the maximum
  175        *         dimensions
  176        * @see #preferredLayoutSize
  177        */
  178       public Dimension maximumLayoutSize(Container target) {
  179           checkContainer(target);
  180           checkRequests();
  181   
  182           Dimension size = new Dimension(xTotal.maximum, yTotal.maximum);
  183           Insets insets = target.getInsets();
  184           size.width += insets.left + insets.right;
  185           size.height += insets.top + insets.bottom;
  186           return size;
  187       }
  188   
  189       /**
  190        * Returns the alignment along the x axis for the container.
  191        *
  192        * @param target the container
  193        * @return the alignment >= 0.0f && <= 1.0f
  194        */
  195       public float getLayoutAlignmentX(Container target) {
  196           checkContainer(target);
  197           checkRequests();
  198           return xTotal.alignment;
  199       }
  200   
  201       /**
  202        * Returns the alignment along the y axis for the container.
  203        *
  204        * @param target the container
  205        * @return the alignment >= 0.0f && <= 1.0f
  206        */
  207       public float getLayoutAlignmentY(Container target) {
  208           checkContainer(target);
  209           checkRequests();
  210           return yTotal.alignment;
  211       }
  212   
  213       /**
  214        * Called by the AWT when the specified container needs to be laid out.
  215        *
  216        * @param target  the container to lay out
  217        *
  218        * @exception AWTError  if the target isn't the container specified to the
  219        *                      constructor
  220        */
  221       public void layoutContainer(Container target) {
  222           checkContainer(target);
  223           checkRequests();
  224   
  225           int nChildren = target.getComponentCount();
  226           int[] xOffsets = new int[nChildren];
  227           int[] xSpans = new int[nChildren];
  228           int[] yOffsets = new int[nChildren];
  229           int[] ySpans = new int[nChildren];
  230   
  231           // determine the child placements
  232           Dimension alloc = target.getSize();
  233           Insets in = target.getInsets();
  234           alloc.width -= in.left + in.right;
  235           alloc.height -= in.top + in.bottom;
  236           SizeRequirements.calculateAlignedPositions(alloc.width, xTotal,
  237                                                      xChildren, xOffsets,
  238                                                      xSpans);
  239           SizeRequirements.calculateAlignedPositions(alloc.height, yTotal,
  240                                                      yChildren, yOffsets,
  241                                                      ySpans);
  242   
  243           // flush changes to the container
  244           for (int i = 0; i < nChildren; i++) {
  245               Component c = target.getComponent(i);
  246               c.setBounds(in.left + xOffsets[i], in.top + yOffsets[i],
  247                           xSpans[i], ySpans[i]);
  248           }
  249       }
  250   
  251       void checkContainer(Container target) {
  252           if (this.target != target) {
  253               throw new AWTError("OverlayLayout can't be shared");
  254           }
  255       }
  256   
  257       void checkRequests() {
  258           if (xChildren == null || yChildren == null) {
  259               // The requests have been invalidated... recalculate
  260               // the request information.
  261               int n = target.getComponentCount();
  262               xChildren = new SizeRequirements[n];
  263               yChildren = new SizeRequirements[n];
  264               for (int i = 0; i < n; i++) {
  265                   Component c = target.getComponent(i);
  266                   Dimension min = c.getMinimumSize();
  267                   Dimension typ = c.getPreferredSize();
  268                   Dimension max = c.getMaximumSize();
  269                   xChildren[i] = new SizeRequirements(min.width, typ.width,
  270                                                       max.width,
  271                                                       c.getAlignmentX());
  272                   yChildren[i] = new SizeRequirements(min.height, typ.height,
  273                                                       max.height,
  274                                                       c.getAlignmentY());
  275               }
  276   
  277               xTotal = SizeRequirements.getAlignedSizeRequirements(xChildren);
  278               yTotal = SizeRequirements.getAlignedSizeRequirements(yChildren);
  279           }
  280       }
  281   
  282       private Container target;
  283       private SizeRequirements[] xChildren;
  284       private SizeRequirements[] yChildren;
  285       private SizeRequirements xTotal;
  286       private SizeRequirements yTotal;
  287   
  288   }

Home » openjdk-7 » javax » swing » [javadoc | source]