/java-1.7.0-openjdk/openjdk/jdk/src/share/classes/java/awt/GridBagLayout.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * accompanied this code).
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 *
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package java.awt;

import java.util.Hashtable;
import java.util.Arrays;

/**
 * The <code>GridBagLayout</code> class is a flexible layout
 * manager that aligns components vertically, horizontally or along their
 * baseline without requiring that the components be of the same size.
 * Each <code>GridBagLayout</code> object maintains a dynamic,
 * rectangular grid of cells, with each component occupying
 * one or more cells, called its <em>display area</em>.
 * <p>
 * Each component managed by a <code>GridBagLayout</code> is associated with
 * an instance of {@link GridBagConstraints}.  The constraints object
 * specifies where a component's display area should be located on the grid
 * and how the component should be positioned within its display area.  In
 * addition to its constraints object, the <code>GridBagLayout</code> also
 * considers each component's minimum and preferred sizes in order to
 * determine a component's size.
 * <p>
 * The overall orientation of the grid depends on the container's
 * {@link ComponentOrientation} property.  For horizontal left-to-right
 * orientations, grid coordinate (0,0) is in the upper left corner of the
 * container with x increasing to the right and y increasing downward.  For
 * horizontal right-to-left orientations, grid coordinate (0,0) is in the upper
 * right corner of the container with x increasing to the left and y
 * increasing downward.
 * <p>
 * To use a grid bag layout effectively, you must customize one or more
 * of the <code>GridBagConstraints</code> objects that are associated
 * with its components. You customize a <code>GridBagConstraints</code>
 * object by setting one or more of its instance variables:
 * <p>
 * <dl>
 * <dt>{@link GridBagConstraints#gridx},
 * {@link GridBagConstraints#gridy}
 * <dd>Specifies the cell containing the leading corner of the component's
 * display area, where the cell at the origin of the grid has address
 * <code>gridx&nbsp;=&nbsp;0</code>,
 * <code>gridy&nbsp;=&nbsp;0</code>.  For horizontal left-to-right layout,
 * a component's leading corner is its upper left.  For horizontal
 * right-to-left layout, a component's leading corner is its upper right.
 * Use <code>GridBagConstraints.RELATIVE</code> (the default value)
 * to specify that the component be placed immediately following
 * (along the x axis for <code>gridx</code> or the y axis for
 * <code>gridy</code>) the component that was added to the container
 * just before this component was added.
 * <dt>{@link GridBagConstraints#gridwidth},
 * {@link GridBagConstraints#gridheight}
 * <dd>Specifies the number of cells in a row (for <code>gridwidth</code>)
 * or column (for <code>gridheight</code>)
 * in the component's display area.
 * The default value is 1.
 * Use <code>GridBagConstraints.REMAINDER</code> to specify
 * that the component's display area will be from <code>gridx</code>
 * to the last cell in the row (for <code>gridwidth</code>)
 * or from <code>gridy</code> to the last cell in the column
 * (for <code>gridheight</code>).
 *
 * Use <code>GridBagConstraints.RELATIVE</code> to specify
 * that the component's display area will be from <code>gridx</code>
 * to the next to the last cell in its row (for <code>gridwidth</code>
 * or from <code>gridy</code> to the next to the last cell in its
 * column (for <code>gridheight</code>).
 *
 * <dt>{@link GridBagConstraints#fill}
 * <dd>Used when the component's display area
 * is larger than the component's requested size
 * to determine whether (and how) to resize the component.
 * Possible values are
 * <code>GridBagConstraints.NONE</code> (the default),
 * <code>GridBagConstraints.HORIZONTAL</code>
 * (make the component wide enough to fill its display area
 * horizontally, but don't change its height),
 * <code>GridBagConstraints.VERTICAL</code>
 * (make the component tall enough to fill its display area
 * vertically, but don't change its width), and
 * <code>GridBagConstraints.BOTH</code>
 * (make the component fill its display area entirely).
 * <dt>{@link GridBagConstraints#ipadx},
 * {@link GridBagConstraints#ipady}
 * <dd>Specifies the component's internal padding within the layout,
 * how much to add to the minimum size of the component.
 * The width of the component will be at least its minimum width
 * plus <code>ipadx</code> pixels. Similarly, the height of
 * the component will be at least the minimum height plus
 * <code>ipady</code> pixels.
 * <dt>{@link GridBagConstraints#insets}
 * <dd>Specifies the component's external padding, the minimum
 * amount of space between the component and the edges of its display area.
 * <dt>{@link GridBagConstraints#anchor}
 * <dd>Specifies where the component should be positioned in its display area.
 * There are three kinds of possible values: absolute, orientation-relative,
 * and baseline-relative
 * Orientation relative values are interpreted relative to the container's
 * <code>ComponentOrientation</code> property while absolute values
 * are not.  Baseline relative values are calculated relative to the
 * baseline.  Valid values are:</dd>
 * <p>
 * <center><table BORDER=0 COLS=3 WIDTH=800
 *        SUMMARY="absolute, relative and baseline values as described above">
 * <tr>
 * <th><P ALIGN="LEFT">Absolute Values</th>
 * <th><P ALIGN="LEFT">Orientation Relative Values</th>
 * <th><P ALIGN="LEFT">Baseline Relative Values</th>
 * </tr>
 * <tr>
 * <td>
 * <li><code>GridBagConstraints.NORTH</code></li>
 * <li><code>GridBagConstraints.SOUTH</code></li>
 * <li><code>GridBagConstraints.WEST</code></li>
 * <li><code>GridBagConstraints.EAST</code></li>
 * <li><code>GridBagConstraints.NORTHWEST</code></li>
 * <li><code>GridBagConstraints.NORTHEAST</code></li>
 * <li><code>GridBagConstraints.SOUTHWEST</code></li>
 * <li><code>GridBagConstraints.SOUTHEAST</code></li>
 * <li><code>GridBagConstraints.CENTER</code> (the default)</li>
 * </td>
 * <td>
 * <li><code>GridBagConstraints.PAGE_START</code></li>
 * <li><code>GridBagConstraints.PAGE_END</code></li>
 * <li><code>GridBagConstraints.LINE_START</code></li>
 * <li><code>GridBagConstraints.LINE_END</code></li>
 * <li><code>GridBagConstraints.FIRST_LINE_START</code></li>
 * <li><code>GridBagConstraints.FIRST_LINE_END</code></li>
 * <li><code>GridBagConstraints.LAST_LINE_START</code></li>
 * <li><code>GridBagConstraints.LAST_LINE_END</code></li>
 * </td>
 * <td>
 * <li><code>GridBagConstraints.BASELINE</code></li>
 * <li><code>GridBagConstraints.BASELINE_LEADING</code></li>
 * <li><code>GridBagConstraints.BASELINE_TRAILING</code></li>
 * <li><code>GridBagConstraints.ABOVE_BASELINE</code></li>
 * <li><code>GridBagConstraints.ABOVE_BASELINE_LEADING</code></li>
 * <li><code>GridBagConstraints.ABOVE_BASELINE_TRAILING</code></li>
 * <li><code>GridBagConstraints.BELOW_BASELINE</code></li>
 * <li><code>GridBagConstraints.BELOW_BASELINE_LEADING</code></li>
 * <li><code>GridBagConstraints.BELOW_BASELINE_TRAILING</code></li>
 * </td>
 * </tr>
 * </table></center><p>
 * <dt>{@link GridBagConstraints#weightx},
 * {@link GridBagConstraints#weighty}
 * <dd>Used to determine how to distribute space, which is
 * important for specifying resizing behavior.
 * Unless you specify a weight for at least one component
 * in a row (<code>weightx</code>) and column (<code>weighty</code>),
 * all the components clump together in the center of their container.
 * This is because when the weight is zero (the default),
 * the <code>GridBagLayout</code> object puts any extra space
 * between its grid of cells and the edges of the container.
 * </dl>
 * <p>
 * Each row may have a baseline; the baseline is determined by the
 * components in that row that have a valid baseline and are aligned
 * along the baseline (the component's anchor value is one of {@code
 * BASELINE}, {@code BASELINE_LEADING} or {@code BASELINE_TRAILING}).
 * If none of the components in the row has a valid baseline, the row
 * does not have a baseline.
 * <p>
 * If a component spans rows it is aligned either to the baseline of
 * the start row (if the baseline-resize behavior is {@code
 * CONSTANT_ASCENT}) or the end row (if the baseline-resize behavior
 * is {@code CONSTANT_DESCENT}).  The row that the component is
 * aligned to is called the <em>prevailing row</em>.
 * <p>
 * The following figure shows a baseline layout and includes a
 * component that spans rows:
 * <center><table summary="Baseline Layout">
 * <tr ALIGN=CENTER>
 * <td>
 * <img src="doc-files/GridBagLayout-baseline.png"
 *  alt="The following text describes this graphic (Figure 1)." ALIGN=center>
 * </td>
 * </table></center>
 * This layout consists of three components:
 * <ul><li>A panel that starts in row 0 and ends in row 1.  The panel
 *   has a baseline-resize behavior of <code>CONSTANT_DESCENT</code> and has
 *   an anchor of <code>BASELINE</code>.  As the baseline-resize behavior
 *   is <code>CONSTANT_DESCENT</code> the prevailing row for the panel is
 *   row 1.
 * <li>Two buttons, each with a baseline-resize behavior of
 *   <code>CENTER_OFFSET</code> and an anchor of <code>BASELINE</code>.
 * </ul>
 * Because the second button and the panel share the same prevailing row,
 * they are both aligned along their baseline.
 * <p>
 * Components positioned using one of the baseline-relative values resize
 * differently than when positioned using an absolute or orientation-relative
 * value.  How components change is dictated by how the baseline of the
 * prevailing row changes.  The baseline is anchored to the
 * bottom of the display area if any components with the same prevailing row
 * have a baseline-resize behavior of <code>CONSTANT_DESCENT</code>,
 * otherwise the baseline is anchored to the top of the display area.
 * The following rules dictate the resize behavior:
 * <ul>
 * <li>Resizable components positioned above the baseline can only
 * grow as tall as the baseline.  For example, if the baseline is at 100
 * and anchored at the top, a resizable component positioned above the
 * baseline can never grow more than 100 units.
 * <li>Similarly, resizable components positioned below the baseline can
 * only grow as high as the difference between the display height and the
 * baseline.
 * <li>Resizable components positioned on the baseline with a
 * baseline-resize behavior of <code>OTHER</code> are only resized if
 * the baseline at the resized size fits within the display area.  If
 * the baseline is such that it does not fit within the display area
 * the component is not resized.
 * <li>Components positioned on the baseline that do not have a
 * baseline-resize behavior of <code>OTHER</code>
 * can only grow as tall as {@code display height - baseline + baseline of component}.
 * </ul>
 * If you position a component along the baseline, but the
 * component does not have a valid baseline, it will be vertically centered
 * in its space.  Similarly if you have positioned a component relative
 * to the baseline and none of the components in the row have a valid
 * baseline the component is vertically centered.
 * <p>
 * The following figures show ten components (all buttons)
 * managed by a grid bag layout.  Figure 2 shows the layout for a horizontal,
 * left-to-right container and Figure 3 shows the layout for a horizontal,
 * right-to-left container.
 * <p>
 * <center><table COLS=2 WIDTH=600 summary="layout">
 * <tr ALIGN=CENTER>
 * <td>
 * <img src="doc-files/GridBagLayout-1.gif" alt="The preceeding text describes this graphic (Figure 1)." ALIGN=center HSPACE=10 VSPACE=7>
 * </td>
 * <td>
 * <img src="doc-files/GridBagLayout-2.gif" alt="The preceeding text describes this graphic (Figure 2)." ALIGN=center HSPACE=10 VSPACE=7>
 * </td>
 * <tr ALIGN=CENTER>
 * <td>Figure 2: Horizontal, Left-to-Right</td>
 * <td>Figure 3: Horizontal, Right-to-Left</td>
 * </tr>
 * </table></center>
 * <p>
 * Each of the ten components has the <code>fill</code> field
 * of its associated <code>GridBagConstraints</code> object
 * set to <code>GridBagConstraints.BOTH</code>.
 * In addition, the components have the following non-default constraints:
 * <p>
 * <ul>
 * <li>Button1, Button2, Button3: <code>weightx&nbsp;=&nbsp;1.0</code>
 * <li>Button4: <code>weightx&nbsp;=&nbsp;1.0</code>,
 * <code>gridwidth&nbsp;=&nbsp;GridBagConstraints.REMAINDER</code>
 * <li>Button5: <code>gridwidth&nbsp;=&nbsp;GridBagConstraints.REMAINDER</code>
 * <li>Button6: <code>gridwidth&nbsp;=&nbsp;GridBagConstraints.RELATIVE</code>
 * <li>Button7: <code>gridwidth&nbsp;=&nbsp;GridBagConstraints.REMAINDER</code>
 * <li>Button8: <code>gridheight&nbsp;=&nbsp;2</code>,
 * <code>weighty&nbsp;=&nbsp;1.0</code>
 * <li>Button9, Button 10:
 * <code>gridwidth&nbsp;=&nbsp;GridBagConstraints.REMAINDER</code>
 * </ul>
 * <p>
 * Here is the code that implements the example shown above:
 * <p>
 * <hr><blockquote><pre>
 * import java.awt.*;
 * import java.util.*;
 * import java.applet.Applet;
 *
 * public class GridBagEx1 extends Applet {
 *
 *     protected void makebutton(String name,
 *                               GridBagLayout gridbag,
 *                               GridBagConstraints c) {
 *         Button button = new Button(name);
 *         gridbag.setConstraints(button, c);
 *         add(button);
 *     }
 *
 *     public void init() {
 *         GridBagLayout gridbag = new GridBagLayout();
 *         GridBagConstraints c = new GridBagConstraints();
 *
 *         setFont(new Font("SansSerif", Font.PLAIN, 14));
 *         setLayout(gridbag);
 *
 *         c.fill = GridBagConstraints.BOTH;
 *         c.weightx = 1.0;
 *         makebutton("Button1", gridbag, c);
 *         makebutton("Button2", gridbag, c);
 *         makebutton("Button3", gridbag, c);
 *
 *         c.gridwidth = GridBagConstraints.REMAINDER; //end row
 *         makebutton("Button4", gridbag, c);
 *
 *         c.weightx = 0.0;                //reset to the default
 *         makebutton("Button5", gridbag, c); //another row
 *
 *         c.gridwidth = GridBagConstraints.RELATIVE; //next-to-last in row
 *         makebutton("Button6", gridbag, c);
 *
 *         c.gridwidth = GridBagConstraints.REMAINDER; //end row
 *         makebutton("Button7", gridbag, c);
 *
 *         c.gridwidth = 1;                //reset to the default
 *         c.gridheight = 2;
 *         c.weighty = 1.0;
 *         makebutton("Button8", gridbag, c);
 *
 *         c.weighty = 0.0;                //reset to the default
 *         c.gridwidth = GridBagConstraints.REMAINDER; //end row
 *         c.gridheight = 1;               //reset to the default
 *         makebutton("Button9", gridbag, c);
 *         makebutton("Button10", gridbag, c);
 *
 *         setSize(300, 100);
 *     }
 *
 *     public static void main(String args[]) {
 *         Frame f = new Frame("GridBag Layout Example");
 *         GridBagEx1 ex1 = new GridBagEx1();
 *
 *         ex1.init();
 *
 *         f.add("Center", ex1);
 *         f.pack();
 *         f.setSize(f.getPreferredSize());
 *         f.show();
 *     }
 * }
 * </pre></blockquote><hr>
 * <p>
 * @author Doug Stein
 * @author Bill Spitzak (orignial NeWS & OLIT implementation)
 * @see       java.awt.GridBagConstraints
 * @see       java.awt.GridBagLayoutInfo
 * @see       java.awt.ComponentOrientation
 * @since JDK1.0
 */
public class GridBagLayout implements LayoutManager2,
java.io.Serializable {

    static final int EMPIRICMULTIPLIER = 2;
    /**
     * This field is no longer used to reserve arrays and keeped for backward
     * compatibility. Previously, this was
     * the maximum number of grid positions (both horizontal and
     * vertical) that could be laid out by the grid bag layout.
     * Current implementation doesn't impose any limits
     * on the size of a grid.
     */
    protected static final int MAXGRIDSIZE = 512;

    /**
     * The smallest grid that can be laid out by the grid bag layout.
     */
    protected static final int MINSIZE = 1;
    /**
     * The preferred grid size that can be laid out by the grid bag layout.
     */
    protected static final int PREFERREDSIZE = 2;

    /**
     * This hashtable maintains the association between
     * a component and its gridbag constraints.
     * The Keys in <code>comptable</code> are the components and the
     * values are the instances of <code>GridBagConstraints</code>.
     *
     * @serial
     * @see java.awt.GridBagConstraints
     */
    protected Hashtable<Component,GridBagConstraints> comptable;

    /**
     * This field holds a gridbag constraints instance
     * containing the default values, so if a component
     * does not have gridbag constraints associated with
     * it, then the component will be assigned a
     * copy of the <code>defaultConstraints</code>.
     *
     * @serial
     * @see #getConstraints(Component)
     * @see #setConstraints(Component, GridBagConstraints)
     * @see #lookupConstraints(Component)
     */
    protected GridBagConstraints defaultConstraints;

    /**
     * This field holds the layout information
     * for the gridbag.  The information in this field
     * is based on the most recent validation of the
     * gridbag.
     * If <code>layoutInfo</code> is <code>null</code>
     * this indicates that there are no components in
     * the gridbag or if there are components, they have
     * not yet been validated.
     *
     * @serial
     * @see #getLayoutInfo(Container, int)
     */
    protected GridBagLayoutInfo layoutInfo;

    /**
     * This field holds the overrides to the column minimum
     * width.  If this field is non-<code>null</code> the values are
     * applied to the gridbag after all of the minimum columns
     * widths have been calculated.
     * If columnWidths has more elements than the number of
     * columns, columns are added to the gridbag to match
     * the number of elements in columnWidth.
     *
     * @serial
     * @see #getLayoutDimensions()
     */
    public int columnWidths[];

    /**
     * This field holds the overrides to the row minimum
     * heights.  If this field is non-<code>null</code> the values are
     * applied to the gridbag after all of the minimum row
     * heights have been calculated.
     * If <code>rowHeights</code> has more elements than the number of
     * rows, rowa are added to the gridbag to match
     * the number of elements in <code>rowHeights</code>.
     *
     * @serial
     * @see #getLayoutDimensions()
     */
    public int rowHeights[];

    /**
     * This field holds the overrides to the column weights.
     * If this field is non-<code>null</code> the values are
     * applied to the gridbag after all of the columns
     * weights have been calculated.
     * If <code>columnWeights[i]</code> &gt; weight for column i, then
     * column i is assigned the weight in <code>columnWeights[i]</code>.
     * If <code>columnWeights</code> has more elements than the number
     * of columns, the excess elements are ignored - they do
     * not cause more columns to be created.
     *
     * @serial
     */
    public double columnWeights[];

    /**
     * This field holds the overrides to the row weights.
     * If this field is non-<code>null</code> the values are
     * applied to the gridbag after all of the rows
     * weights have been calculated.
     * If <code>rowWeights[i]</code> &gt; weight for row i, then
     * row i is assigned the weight in <code>rowWeights[i]</code>.
     * If <code>rowWeights</code> has more elements than the number
     * of rows, the excess elements are ignored - they do
     * not cause more rows to be created.
     *
     * @serial
     */
    public double rowWeights[];

    /**
     * The component being positioned.  This is set before calling into
     * <code>adjustForGravity</code>.
     */
    private Component componentAdjusting;

    /**
     * Creates a grid bag layout manager.
     */
    public GridBagLayout () {
        comptable = new Hashtable<Component,GridBagConstraints>();
        defaultConstraints = new GridBagConstraints();
    }

    /**
     * Sets the constraints for the specified component in this layout.
     * @param       comp the component to be modified
     * @param       constraints the constraints to be applied
     */
    public void setConstraints(Component comp, GridBagConstraints constraints) {
        comptable.put(comp, (GridBagConstraints)constraints.clone());
    }

    /**
     * Gets the constraints for the specified component.  A copy of
     * the actual <code>GridBagConstraints</code> object is returned.
     * @param       comp the component to be queried
     * @return      the constraint for the specified component in this
     *                  grid bag layout; a copy of the actual constraint
     *                  object is returned
     */
    public GridBagConstraints getConstraints(Component comp) {
        GridBagConstraints constraints = comptable.get(comp);
        if (constraints == null) {
            setConstraints(comp, defaultConstraints);
            constraints = comptable.get(comp);
        }
        return (GridBagConstraints)constraints.clone();
    }

    /**
     * Retrieves the constraints for the specified component.
     * The return value is not a copy, but is the actual
     * <code>GridBagConstraints</code> object used by the layout mechanism.
     * <p>
     * If <code>comp</code> is not in the <code>GridBagLayout</code>,
     * a set of default <code>GridBagConstraints</code> are returned.
     * A <code>comp</code> value of <code>null</code> is invalid
     * and returns <code>null</code>.
     *
     * @param       comp the component to be queried
     * @return      the contraints for the specified component
     */
    protected GridBagConstraints lookupConstraints(Component comp) {
        GridBagConstraints constraints = comptable.get(comp);
        if (constraints == null) {
            setConstraints(comp, defaultConstraints);
            constraints = comptable.get(comp);
        }
        return constraints;
    }

    /**
     * Removes the constraints for the specified component in this layout
     * @param       comp the component to be modified
     */
    private void removeConstraints(Component comp) {
        comptable.remove(comp);
    }

    /**
     * Determines the origin of the layout area, in the graphics coordinate
     * space of the target container.  This value represents the pixel
     * coordinates of the top-left corner of the layout area regardless of
     * the <code>ComponentOrientation</code> value of the container.  This
     * is distinct from the grid origin given by the cell coordinates (0,0).
     * Most applications do not call this method directly.
     * @return     the graphics origin of the cell in the top-left
     *             corner of the layout grid
     * @see        java.awt.ComponentOrientation
     * @since      JDK1.1
     */
    public Point getLayoutOrigin () {
        Point origin = new Point(0,0);
        if (layoutInfo != null) {
            origin.x = layoutInfo.startx;
            origin.y = layoutInfo.starty;
        }
        return origin;
    }

    /**
     * Determines column widths and row heights for the layout grid.
     * <p>
     * Most applications do not call this method directly.
     * @return     an array of two arrays, containing the widths
     *                       of the layout columns and
     *                       the heights of the layout rows
     * @since      JDK1.1
     */
    public int [][] getLayoutDimensions () {
        if (layoutInfo == null)
            return new int[2][0];

        int dim[][] = new int [2][];
        dim[0] = new int[layoutInfo.width];
        dim[1] = new int[layoutInfo.height];

        System.arraycopy(layoutInfo.minWidth, 0, dim[0], 0, layoutInfo.width);
        System.arraycopy(layoutInfo.minHeight, 0, dim[1], 0, layoutInfo.height);

        return dim;
    }

    /**
     * Determines the weights of the layout grid's columns and rows.
     * Weights are used to calculate how much a given column or row
     * stretches beyond its preferred size, if the layout has extra
     * room to fill.
     * <p>
     * Most applications do not call this method directly.
     * @return      an array of two arrays, representing the
     *                    horizontal weights of the layout columns
     *                    and the vertical weights of the layout rows
     * @since       JDK1.1
     */
    public double [][] getLayoutWeights () {
        if (layoutInfo == null)
            return new double[2][0];

        double weights[][] = new double [2][];
        weights[0] = new double[layoutInfo.width];
        weights[1] = new double[layoutInfo.height];

        System.arraycopy(layoutInfo.weightX, 0, weights[0], 0, layoutInfo.width);
        System.arraycopy(layoutInfo.weightY, 0, weights[1], 0, layoutInfo.height);

        return weights;
    }

    /**
     * Determines which cell in the layout grid contains the point
     * specified by <code>(x,&nbsp;y)</code>. Each cell is identified
     * by its column index (ranging from 0 to the number of columns
     * minus 1) and its row index (ranging from 0 to the number of
     * rows minus 1).
     * <p>
     * If the <code>(x,&nbsp;y)</code> point lies
     * outside the grid, the following rules are used.
     * The column index is returned as zero if <code>x</code> lies to the
     * left of the layout for a left-to-right container or to the right of
     * the layout for a right-to-left container.  The column index is returned
     * as the number of columns if <code>x</code> lies
     * to the right of the layout in a left-to-right container or to the left
     * in a right-to-left container.
     * The row index is returned as zero if <code>y</code> lies above the
     * layout, and as the number of rows if <code>y</code> lies
     * below the layout.  The orientation of a container is determined by its
     * <code>ComponentOrientation</code> property.
     * @param      x    the <i>x</i> coordinate of a point
     * @param      y    the <i>y</i> coordinate of a point
     * @return     an ordered pair of indexes that indicate which cell
     *             in the layout grid contains the point
     *             (<i>x</i>,&nbsp;<i>y</i>).
     * @see        java.awt.ComponentOrientation
     * @since      JDK1.1
     */
    public Point location(int x, int y) {
        Point loc = new Point(0,0);
        int i, d;

        if (layoutInfo == null)
            return loc;

        d = layoutInfo.startx;
        if (!rightToLeft) {
            for (i=0; i<layoutInfo.width; i++) {
                d += layoutInfo.minWidth[i];
                if (d > x)
                    break;
            }
        } else {
            for (i=layoutInfo.width-1; i>=0; i--) {
                if (d > x)
                    break;
                d += layoutInfo.minWidth[i];
            }
            i++;
        }
        loc.x = i;

        d = layoutInfo.starty;
        for (i=0; i<layoutInfo.height; i++) {
            d += layoutInfo.minHeight[i];
            if (d > y)
                break;
        }
        loc.y = i;

        return loc;
    }

    /**
     * Has no effect, since this layout manager does not use a per-component string.
     */
    public void addLayoutComponent(String name, Component comp) {
    }

    /**
     * Adds the specified component to the layout, using the specified
     * <code>constraints</code> object.  Note that constraints
     * are mutable and are, therefore, cloned when cached.
     *
     * @param      comp         the component to be added
     * @param      constraints  an object that determines how
     *                          the component is added to the layout
     * @exception IllegalArgumentException if <code>constraints</code>
     *            is not a <code>GridBagConstraint</code>
     */
    public void addLayoutComponent(Component comp, Object constraints) {
        if (constraints instanceof GridBagConstraints) {
            setConstraints(comp, (GridBagConstraints)constraints);
        } else if (constraints != null) {
            throw new IllegalArgumentException("cannot add to layout: constraints must be a GridBagConstraint");
        }
    }

    /**
     * Removes the specified component from this layout.
     * <p>
     * Most applications do not call this method directly.
     * @param    comp   the component to be removed.
     * @see      java.awt.Container#remove(java.awt.Component)
     * @see      java.awt.Container#removeAll()
     */
    public void removeLayoutComponent(Component comp) {
        removeConstraints(comp);
    }

    /**
     * Determines the preferred size of the <code>parent</code>
     * container using this grid bag layout.
     * <p>
     * Most applications do not call this method directly.
     *
     * @param     parent   the container in which to do the layout
     * @see       java.awt.Container#getPreferredSize
     * @return the preferred size of the <code>parent</code>
     *  container
     */
    public Dimension preferredLayoutSize(Container parent) {
        GridBagLayoutInfo info = getLayoutInfo(parent, PREFERREDSIZE);
        return getMinSize(parent, info);
    }

    /**
     * Determines the minimum size of the <code>parent</code> container
     * using this grid bag layout.
     * <p>
     * Most applications do not call this method directly.
     * @param     parent   the container in which to do the layout
     * @see       java.awt.Container#doLayout
     * @return the minimum size of the <code>parent</code> container
     */
    public Dimension minimumLayoutSize(Container parent) {
        GridBagLayoutInfo info = getLayoutInfo(parent, MINSIZE);
        return getMinSize(parent, info);
    }

    /**
     * Returns the maximum dimensions for this layout given the components
     * in the specified target container.
     * @param target the container which needs to be laid out
     * @see Container
     * @see #minimumLayoutSize(Container)
     * @see #preferredLayoutSize(Container)
     * @return the maximum dimensions for this layout
     */
    public Dimension maximumLayoutSize(Container target) {
        return new Dimension(Integer.MAX_VALUE, Integer.MAX_VALUE);
    }

    /**
     * Returns the alignment along the x axis.  This specifies how
     * the component would like to be aligned relative to other
     * components.  The value should be a number between 0 and 1
     * where 0 represents alignment along the origin, 1 is aligned
     * the furthest away from the origin, 0.5 is centered, etc.
     * <p>
     * @return the value <code>0.5f</code> to indicate centered
     */
    public float getLayoutAlignmentX(Container parent) {
        return 0.5f;
    }

    /**
     * Returns the alignment along the y axis.  This specifies how
     * the component would like to be aligned relative to other
     * components.  The value should be a number between 0 and 1
     * where 0 represents alignment along the origin, 1 is aligned
     * the furthest away from the origin, 0.5 is centered, etc.
     * <p>
     * @return the value <code>0.5f</code> to indicate centered
     */
    public float getLayoutAlignmentY(Container parent) {
        return 0.5f;
    }

    /**
     * Invalidates the layout, indicating that if the layout manager
     * has cached information it should be discarded.
     */
    public void invalidateLayout(Container target) {
    }

    /**
     * Lays out the specified container using this grid bag layout.
     * This method reshapes components in the specified container in
     * order to satisfy the contraints of this <code>GridBagLayout</code>
     * object.
     * <p>
     * Most applications do not call this method directly.
     * @param parent the container in which to do the layout
     * @see java.awt.Container
     * @see java.awt.Container#doLayout
     */
    public void layoutContainer(Container parent) {
        arrangeGrid(parent);
    }

    /**
     * Returns a string representation of this grid bag layout's values.
     * @return     a string representation of this grid bag layout.
     */
    public String toString() {
        return getClass().getName();
    }

    /**
     * Print the layout information.  Useful for debugging.
     */

    /* DEBUG
     *
     *  protected void dumpLayoutInfo(GridBagLayoutInfo s) {
     *    int x;
     *
     *    System.out.println("Col\tWidth\tWeight");
     *    for (x=0; x<s.width; x++) {
     *      System.out.println(x + "\t" +
     *                   s.minWidth[x] + "\t" +
     *                   s.weightX[x]);
     *    }
     *    System.out.println("Row\tHeight\tWeight");
     *    for (x=0; x<s.height; x++) {
     *      System.out.println(x + "\t" +
     *                   s.minHeight[x] + "\t" +
     *                   s.weightY[x]);
     *    }
     *  }
     */

    /**
     * Print the layout constraints.  Useful for debugging.
     */

    /* DEBUG
     *
     *  protected void dumpConstraints(GridBagConstraints constraints) {
     *    System.out.println(
     *                 "wt " +
     *                 constraints.weightx +
     *                 " " +
     *                 constraints.weighty +
     *                 ", " +
     *
     *                 "box " +
     *                 constraints.gridx +
     *                 " " +
     *                 constraints.gridy +
     *                 " " +
     *                 constraints.gridwidth +
     *                 " " +
     *                 constraints.gridheight +
     *                 ", " +
     *
     *                 "min " +
     *                 constraints.minWidth +
     *                 " " +
     *                 constraints.minHeight +
     *                 ", " +
     *
     *                 "pad " +
     *                 constraints.insets.bottom +
     *                 " " +
     *                 constraints.insets.left +
     *                 " " +
     *                 constraints.insets.right +
     *                 " " +
     *                 constraints.insets.top +
     *                 " " +
     *                 constraints.ipadx +
     *                 " " +
     *                 constraints.ipady);
     *  }
     */

    /**
     * Fills in an instance of <code>GridBagLayoutInfo</code> for the
     * current set of managed children. This requires three passes through the
     * set of children:
     *
     * <ol>
     * <li>Figure out the dimensions of the layout grid.
     * <li>Determine which cells the components occupy.
     * <li>Distribute the weights and min sizes amoung the rows/columns.
     * </ol>
     *
     * This also caches the minsizes for all the children when they are
     * first encountered (so subsequent loops don't need to ask again).
     * <p>
     * This method should only be used internally by
     * <code>GridBagLayout</code>.
     *
     * @param parent  the layout container
     * @param sizeflag either <code>PREFERREDSIZE</code> or
     *   <code>MINSIZE</code>
     * @return the <code>GridBagLayoutInfo</code> for the set of children
     * @since 1.4
     */
    protected GridBagLayoutInfo getLayoutInfo(Container parent, int sizeflag) {
        return GetLayoutInfo(parent, sizeflag);
    }

    /*
     * Calculate maximum array sizes to allocate arrays without ensureCapacity
     * we may use preCalculated sizes in whole class because of upper estimation of
     * maximumArrayXIndex and maximumArrayYIndex.
     */

    private long[]  preInitMaximumArraySizes(Container parent){
        Component components[] = parent.getComponents();
        Component comp;
        GridBagConstraints constraints;
        int curX, curY;
        int curWidth, curHeight;
        int preMaximumArrayXIndex = 0;
        int preMaximumArrayYIndex = 0;
        long [] returnArray = new long[2];

        for (int compId = 0 ; compId < components.length ; compId++) {
            comp = components[compId];
            if (!comp.isVisible()) {
                continue;
            }

            constraints = lookupConstraints(comp);
            curX = constraints.gridx;
            curY = constraints.gridy;
            curWidth = constraints.gridwidth;
            curHeight = constraints.gridheight;

            // -1==RELATIVE, means that column|row equals to previously added component,
            // since each next Component with gridx|gridy == RELATIVE starts from
            // previous position, so we should start from previous component which
            // already used in maximumArray[X|Y]Index calculation. We could just increase
            // maximum by 1 to handle situation when component with gridx=-1 was added.
            if (curX < 0){
                curX = ++preMaximumArrayYIndex;
            }
            if (curY < 0){
                curY = ++preMaximumArrayXIndex;
            }
            // gridwidth|gridheight may be equal to RELATIVE (-1) or REMAINDER (0)
            // in any case using 1 instead of 0 or -1 should be sufficient to for
            // correct maximumArraySizes calculation
            if (curWidth <= 0){
                curWidth = 1;
            }
            if (curHeight <= 0){
                curHeight = 1;
            }

            preMaximumArrayXIndex = Math.max(curY + curHeight, preMaximumArrayXIndex);
            preMaximumArrayYIndex = Math.max(curX + curWidth, preMaximumArrayYIndex);
        } //for (components) loop
        // Must specify index++ to allocate well-working arrays.
        /* fix for 4623196.
         * now return long array instead of Point
         */
        returnArray[0] = preMaximumArrayXIndex;
        returnArray[1] = preMaximumArrayYIndex;
        return returnArray;
    } //PreInitMaximumSizes

    /**
     * This method is obsolete and supplied for backwards
     * compatability only; new code should call {@link
     * #getLayoutInfo(java.awt.Container, int) getLayoutInfo} instead.
     * This method is the same as <code>getLayoutInfo</code>;
     * refer to <code>getLayoutInfo</code> for details on parameters
     * and return value.
     */
    protected GridBagLayoutInfo GetLayoutInfo(Container parent, int sizeflag) {
        synchronized (parent.getTreeLock()) {
            GridBagLayoutInfo r;
            Component comp;
            GridBagConstraints constraints;
            Dimension d;
            Component components[] = parent.getComponents();
            // Code below will address index curX+curWidth in the case of yMaxArray, weightY
            // ( respectively curY+curHeight for xMaxArray, weightX ) where
            //  curX in 0 to preInitMaximumArraySizes.y
            // Thus, the maximum index that could
            // be calculated in the following code is curX+curX.
            // EmpericMultier equals 2 because of this.

            int layoutWidth, layoutHeight;
            int []xMaxArray;
            int []yMaxArray;
            int compindex, i, k, px, py, pixels_diff, nextSize;
            int curX = 0; // constraints.gridx
            int curY = 0; // constraints.gridy
            int curWidth = 1;  // constraints.gridwidth
            int curHeight = 1;  // constraints.gridheight
            int curRow, curCol;
            double weight_diff, weight;
            int maximumArrayXIndex = 0;
            int maximumArrayYIndex = 0;
            int anchor;

            /*
             * Pass #1
             *
             * Figure out the dimensions of the layout grid (use a value of 1 for
             * zero or negative widths and heights).
             */

            layoutWidth = layoutHeight = 0;
            curRow = curCol = -1;
            long [] arraySizes = preInitMaximumArraySizes(parent);

            /* fix for 4623196.
             * If user try to create a very big grid we can
             * get NegativeArraySizeException because of integer value
             * overflow (EMPIRICMULTIPLIER*gridSize might be more then Integer.MAX_VALUE).
             * We need to detect this situation and try to create a
             * grid with Integer.MAX_VALUE size instead.
             */
            maximumArrayXIndex = (EMPIRICMULTIPLIER * arraySizes[0] > Integer.MAX_VALUE )? Integer.MAX_VALUE : EMPIRICMULTIPLIER*(int)arraySizes[0];
            maximumArrayYIndex = (EMPIRICMULTIPLIER * arraySizes[1] > Integer.MAX_VALUE )? Integer.MAX_VALUE : EMPIRICMULTIPLIER*(int)arraySizes[1];

            if (rowHeights != null){
                maximumArrayXIndex = Math.max(maximumArrayXIndex, rowHeights.length);
            }
            if (columnWidths != null){
                maximumArrayYIndex = Math.max(maximumArrayYIndex, columnWidths.length);
            }

            xMaxArray = new int[maximumArrayXIndex];
            yMaxArray = new int[maximumArrayYIndex];

            boolean hasBaseline = false;
            for (compindex = 0 ; compindex < components.length ; compindex++) {
                comp = components[compindex];
                if (!comp.isVisible())
                    continue;
                constraints = lookupConstraints(comp);

                curX = constraints.gridx;
                curY = constraints.gridy;
                curWidth = constraints.gridwidth;
                if (curWidth <= 0)
                    curWidth = 1;
                curHeight = constraints.gridheight;
                if (curHeight <= 0)
                    curHeight = 1;

                /* If x or y is negative, then use relative positioning: */
                if (curX < 0 && curY < 0) {
                    if (curRow >= 0)
                        curY = curRow;
                    else if (curCol >= 0)
                        curX = curCol;
                    else
                        curY = 0;
                }
                if (curX < 0) {
                    px = 0;
                    for (i = curY; i < (curY + curHeight); i++) {
                        px = Math.max(px, xMaxArray[i]);
                    }

                    curX = px - curX - 1;
                    if(curX < 0)
                        curX = 0;
                }
                else if (curY < 0) {
                    py = 0;
                    for (i = curX; i < (curX + curWidth); i++) {
                        py = Math.max(py, yMaxArray[i]);
                    }
                    curY = py - curY - 1;
                    if(curY < 0)
                        curY = 0;
                }

                /* Adjust the grid width and height
                 *  fix for 5005945: unneccessary loops removed
                 */
                px = curX + curWidth;
                if (layoutWidth < px) {
                    layoutWidth = px;
                }
                py = curY + curHeight;
                if (layoutHeight < py) {
                    layoutHeight = py;
                }

                /* Adjust xMaxArray and yMaxArray */
                for (i = curX; i < (curX + curWidth); i++) {
                    yMaxArray[i] =py;
                }
                for (i = curY; i < (curY + curHeight); i++) {
                    xMaxArray[i] = px;
                }


                /* Cache the current slave's size. */
                if (sizeflag == PREFERREDSIZE)
                    d = comp.getPreferredSize();
                else
                    d = comp.getMinimumSize();
                constraints.minWidth = d.width;
                constraints.minHeight = d.height;
                if (calculateBaseline(comp, constraints, d)) {
                    hasBaseline = true;
                }

                /* Zero width and height must mean that this is the last item (or
                 * else something is wrong). */
                if (constraints.gridheight == 0 && constraints.gridwidth == 0)
                    curRow = curCol = -1;

                /* Zero width starts a new row */
                if (constraints.gridheight == 0 && curRow < 0)
                    curCol = curX + curWidth;

                /* Zero height starts a new column */
                else if (constraints.gridwidth == 0 && curCol < 0)
                    curRow = curY + curHeight;
            } //for (components) loop


            /*
             * Apply minimum row/column dimensions
             */
            if (columnWidths != null && layoutWidth < columnWidths.length)
                layoutWidth = columnWidths.length;
            if (rowHeights != null && layoutHeight < rowHeights.length)
                layoutHeight = rowHeights.length;

            r = new GridBagLayoutInfo(layoutWidth, layoutHeight);

            /*
             * Pass #2
             *
             * Negative values for gridX are filled in with the current x value.
             * Negative values for gridY are filled in with the current y value.
             * Negative or zero values for gridWidth and gridHeight end the current
             *  row or column, respectively.
             */

            curRow = curCol = -1;

            Arrays.fill(xMaxArray, 0);
            Arrays.fill(yMaxArray, 0);

            int[] maxAscent = null;
            int[] maxDescent = null;
            short[] baselineType = null;

            if (hasBaseline) {
                r.maxAscent = maxAscent = new int[layoutHeight];
                r.maxDescent = maxDescent = new int[layoutHeight];
                r.baselineType = baselineType = new short[layoutHeight];
                r.hasBaseline = true;
            }


            for (compindex = 0 ; compindex < components.length ; compindex++) {
                comp = components[compindex];
                if (!comp.isVisible())
                    continue;
                constraints = lookupConstraints(comp);

                curX = constraints.gridx;
                curY = constraints.gridy;
                curWidth = constraints.gridwidth;
                curHeight = constraints.gridheight;

                /* If x or y is negative, then use relative positioning: */
                if (curX < 0 && curY < 0) {
                    if(curRow >= 0)
                        curY = curRow;
                    else if(curCol >= 0)
                        curX = curCol;
                    else
                        curY = 0;
                }

                if (curX < 0) {
                    if (curHeight <= 0) {
                        curHeight += r.height - curY;
                        if (curHeight < 1)
                            curHeight = 1;
                    }

                    px = 0;
                    for (i = curY; i < (curY + curHeight); i++)
                        px = Math.max(px, xMaxArray[i]);

                    curX = px - curX - 1;
                    if(curX < 0)
                        curX = 0;
                }
                else if (curY < 0) {
                    if (curWidth <= 0) {
                        curWidth += r.width - curX;
                        if (curWidth < 1)
                            curWidth = 1;
                    }

                    py = 0;
                    for (i = curX; i < (curX + curWidth); i++){
                        py = Math.max(py, yMaxArray[i]);
                    }

                    curY = py - curY - 1;
                    if(curY < 0)
                        curY = 0;
                }

                if (curWidth <= 0) {
                    curWidth += r.width - curX;
                    if (curWidth < 1)
                        curWidth = 1;
                }

                if (curHeight <= 0) {
                    curHeight += r.height - curY;
                    if (curHeight < 1)
                        curHeight = 1;
                }

                px = curX + curWidth;
                py = curY + curHeight;

                for (i = curX; i < (curX + curWidth); i++) { yMaxArray[i] = py; }
                for (i = curY; i < (curY + curHeight); i++) { xMaxArray[i] = px; }

                /* Make negative sizes start a new row/column */
                if (constraints.gridheight == 0 && constraints.gridwidth == 0)
                    curRow = curCol = -1;
                if (constraints.gridheight == 0 && curRow < 0)
                    curCol = curX + curWidth;
                else if (constraints.gridwidth == 0 && curCol < 0)
                    curRow = curY + curHeight;

                /* Assign the new values to the gridbag slave */
                constraints.tempX = curX;
                constraints.tempY = curY;
                constraints.tempWidth = curWidth;
                constraints.tempHeight = curHeight;

                anchor = constraints.anchor;
                if (hasBaseline) {
                    switch(anchor)…

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