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package java.awt;

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


The GridBagLayout 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 GridBagLayout object maintains a dynamic, rectangular grid of cells, with each component occupying one or more cells, called its display area.

 Each component managed by a GridBagLayout is associated with an instance of 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 GridBagLayout also considers each component's minimum and preferred sizes in order to determine a component's size. 
 The overall orientation of the grid depends on the container's 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. 
 To use a grid bag layout effectively, you must customize one or more of the GridBagConstraints objects that are associated with its components. You customize a GridBagConstraints object by setting one or more of its instance variables: 


GridBagConstraints.gridx, GridBagConstraints.gridy 
Specifies the cell containing the leading corner of the component's
display area, where the cell at the origin of the grid has address
gridx = 0,
gridy = 0. 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 GridBagConstraints.RELATIVE (the default value) to specify that the component be placed immediately following (along the x axis for gridx or the y axis for gridy) the component that was added to the container just before this component was added. 
GridBagConstraints.gridwidth, GridBagConstraints.gridheight 
Specifies the number of cells in a row (for gridwidth) or column (for gridheight) in the component's display area. The default value is 1. Use GridBagConstraints.REMAINDER to specify that the component's display area will be from gridx to the last cell in the row (for gridwidth) or from gridy to the last cell in the column (for gridheight). Use GridBagConstraints.RELATIVE to specify that the component's display area will be from gridx to the next to the last cell in its row (for gridwidth or from gridy to the next to the last cell in its column (for gridheight). 
GridBagConstraints.fill 
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 GridBagConstraints.NONE (the default), GridBagConstraints.HORIZONTAL (make the component wide enough to fill its display area horizontally, but don't change its height), GridBagConstraints.VERTICAL (make the component tall enough to fill its display area vertically, but don't change its width), and GridBagConstraints.BOTH (make the component fill its display area entirely). 
GridBagConstraints.ipadx, GridBagConstraints.ipady 
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 ipadx pixels. Similarly, the height of the component will be at least the minimum height plus ipady pixels. 
GridBagConstraints.insets 
Specifies the component's external padding, the minimum
amount of space between the component and the edges of its display area.

GridBagConstraints.anchor 
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 ComponentOrientation property while absolute values are not. Baseline relative values are calculated relative to the baseline. Valid values are: 

Absolute, relative and baseline values as described above




Absolute Values


Orientation Relative Values


Baseline Relative Values









    

  • GridBagConstraints.NORTH
    • 

  • GridBagConstraints.SOUTH
    • 

  • GridBagConstraints.WEST
    • 

  • GridBagConstraints.EAST
    • 

  • GridBagConstraints.NORTHWEST
    • 

  • GridBagConstraints.NORTHEAST
    • 

  • GridBagConstraints.SOUTHWEST
    • 

  • GridBagConstraints.SOUTHEAST
    • 

  • GridBagConstraints.CENTER (the default)
    • 





    

  • GridBagConstraints.PAGE_START
    • 

  • GridBagConstraints.PAGE_END
    • 

  • GridBagConstraints.LINE_START
    • 

  • GridBagConstraints.LINE_END
    • 

  • GridBagConstraints.FIRST_LINE_START
    • 

  • GridBagConstraints.FIRST_LINE_END
    • 

  • GridBagConstraints.LAST_LINE_START
    • 

  • GridBagConstraints.LAST_LINE_END
    • 





    

  • GridBagConstraints.BASELINE
    • 

  • GridBagConstraints.BASELINE_LEADING
    • 

  • GridBagConstraints.BASELINE_TRAILING
    • 

  • GridBagConstraints.ABOVE_BASELINE
    • 

  • GridBagConstraints.ABOVE_BASELINE_LEADING
    • 

  • GridBagConstraints.ABOVE_BASELINE_TRAILING
    • 

  • GridBagConstraints.BELOW_BASELINE
    • 

  • GridBagConstraints.BELOW_BASELINE_LEADING
    • 

  • GridBagConstraints.BELOW_BASELINE_TRAILING
    • 









GridBagConstraints.weightx, GridBagConstraints.weighty 
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 (weightx) and column (weighty), all the components clump together in the center of their container. This is because when the weight is zero (the default), the GridBagLayout object puts any extra space between its grid of cells and the edges of the container. 


 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 
BASELINE, BASELINE_LEADING or BASELINE_TRAILING). If none of the components in the row has a valid baseline, the row does not have a baseline. 
 If a component spans rows it is aligned either to the baseline of the start row (if the baseline-resize behavior is 
CONSTANT_ASCENT) or the end row (if the baseline-resize behavior is CONSTANT_DESCENT). The row that the component is aligned to is called the prevailing row.


The following figure shows a baseline layout and includes a
component that spans rows:


Baseline Layout







This layout consists of three components:

  • A panel that starts in row 0 and ends in row 1. The panel has a baseline-resize behavior of CONSTANT_DESCENT and has an anchor of BASELINE. As the baseline-resize behavior is CONSTANT_DESCENT the prevailing row for the panel is row 1. 
  • Two buttons, each with a baseline-resize behavior of CENTER_OFFSET and an anchor of BASELINE. 

Because the second button and the panel share the same prevailing row,
they are both aligned along their baseline.

 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 CONSTANT_DESCENT, otherwise the baseline is anchored to the top of the display area. The following rules dictate the resize behavior: 
    

  • 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.

  • Similarly, resizable components positioned below the baseline can
only grow as high as the difference between the display height and the
baseline.

  • Resizable components positioned on the baseline with a baseline-resize behavior of OTHER 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. 
  • Components positioned on the baseline that do not have a baseline-resize behavior of OTHER can only grow as tall as display height - baseline + baseline of component. 

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.


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.


Figures










Figure 2: Horizontal, Left-to-Right
Figure 3: Horizontal, Right-to-Left





 Each of the ten components has the fill field of its associated GridBagConstraints object set to GridBagConstraints.BOTH. In addition, the components have the following non-default constraints: 
    

  • Button1, Button2, Button3: weightx = 1.0

  • Button4: weightx = 1.0,
gridwidth = GridBagConstraints.REMAINDER

  • Button5: gridwidth = GridBagConstraints.REMAINDER

  • Button6: gridwidth = GridBagConstraints.RELATIVE

  • Button7: gridwidth = GridBagConstraints.REMAINDER

  • Button8: gridheight = 2,
weighty = 1.0

  • Button9, Button 10:
gridwidth = GridBagConstraints.REMAINDER




Here is the code that implements the example shown above:

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();
    }
}



Author:Doug Stein, Bill Spitzak (orignial NeWS & OLIT implementation)
See Also:
Since:1.0
/**
 * The {@code GridBagLayout} 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} 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} 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} 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} objects that are associated
 * with its components. You customize a {@code GridBagConstraints}
 * object by setting one or more of its instance variables:
 *
 * <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} (the default value)
 * to specify that the component be placed immediately following
 * (along the x axis for {@code gridx} or the y axis for
 * {@code gridy}) 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})
 * or column (for {@code gridheight})
 * in the component's display area.
 * The default value is 1.
 * Use {@code GridBagConstraints.REMAINDER} to specify
 * that the component's display area will be from {@code gridx}
 * to the last cell in the row (for {@code gridwidth})
 * or from {@code gridy} to the last cell in the column
 * (for {@code gridheight}).
 *
 * Use {@code GridBagConstraints.RELATIVE} to specify
 * that the component's display area will be from {@code gridx}
 * to the next to the last cell in its row (for {@code gridwidth}
 * or from {@code gridy} to the next to the last cell in its
 * column (for {@code gridheight}).
 *
 * <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} (the default),
 * {@code GridBagConstraints.HORIZONTAL}
 * (make the component wide enough to fill its display area
 * horizontally, but don't change its height),
 * {@code GridBagConstraints.VERTICAL}
 * (make the component tall enough to fill its display area
 * vertically, but don't change its width), and
 * {@code GridBagConstraints.BOTH}
 * (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} pixels. Similarly, the height of
 * the component will be at least the minimum height plus
 * {@code ipady} 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} property while absolute values
 * are not.  Baseline relative values are calculated relative to the
 * baseline.  Valid values are:
 *
 * <table class="striped" style="margin: 0px auto">
 * <caption>Absolute, relative and baseline values as described above</caption>
 * <thead>
 * <tr>
 * <th><p style="text-align:center">Absolute Values</th>
 * <th><p style="text-align:center">Orientation Relative Values</th>
 * <th><p style="text-align:center">Baseline Relative Values</th>
 * </tr>
 * </thead>
 * <tbody>
 * <tr>
 * <td>
 * <ul style="list-style-type:none">
 * <li>{@code GridBagConstraints.NORTH}</li>
 * <li>{@code GridBagConstraints.SOUTH}</li>
 * <li>{@code GridBagConstraints.WEST}</li>
 * <li>{@code GridBagConstraints.EAST}</li>
 * <li>{@code GridBagConstraints.NORTHWEST}</li>
 * <li>{@code GridBagConstraints.NORTHEAST}</li>
 * <li>{@code GridBagConstraints.SOUTHWEST}</li>
 * <li>{@code GridBagConstraints.SOUTHEAST}</li>
 * <li>{@code GridBagConstraints.CENTER} (the default)</li>
 * </ul>
 * </td>
 * <td>
 * <ul style="list-style-type:none">
 * <li>{@code GridBagConstraints.PAGE_START}</li>
 * <li>{@code GridBagConstraints.PAGE_END}</li>
 * <li>{@code GridBagConstraints.LINE_START}</li>
 * <li>{@code GridBagConstraints.LINE_END}</li>
 * <li>{@code GridBagConstraints.FIRST_LINE_START}</li>
 * <li>{@code GridBagConstraints.FIRST_LINE_END}</li>
 * <li>{@code GridBagConstraints.LAST_LINE_START}</li>
 * <li>{@code GridBagConstraints.LAST_LINE_END}</li>
 * </ul>
 * </td>
 * <td>
 * <ul style="list-style-type:none">
 * <li>{@code GridBagConstraints.BASELINE}</li>
 * <li>{@code GridBagConstraints.BASELINE_LEADING}</li>
 * <li>{@code GridBagConstraints.BASELINE_TRAILING}</li>
 * <li>{@code GridBagConstraints.ABOVE_BASELINE}</li>
 * <li>{@code GridBagConstraints.ABOVE_BASELINE_LEADING}</li>
 * <li>{@code GridBagConstraints.ABOVE_BASELINE_TRAILING}</li>
 * <li>{@code GridBagConstraints.BELOW_BASELINE}</li>
 * <li>{@code GridBagConstraints.BELOW_BASELINE_LEADING}</li>
 * <li>{@code GridBagConstraints.BELOW_BASELINE_TRAILING}</li>
 * </ul>
 * </td>
 * </tr>
 * </tbody>
 * </table>
 * <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}) and column ({@code weighty}),
 * all the components clump together in the center of their container.
 * This is because when the weight is zero (the default),
 * the {@code GridBagLayout} 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:
 * <table class="borderless" style="margin: 0px auto">
 * <caption>Baseline Layout</caption>
 * <tr style="text-align:center">
 * <td>
 * <img src="doc-files/GridBagLayout-baseline.png"
 *  alt="The following text describes this graphic (Figure 1)." style="float:center">
 * </td>
 * </table>
 * 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} and has
 *   an anchor of {@code BASELINE}.  As the baseline-resize behavior
 *   is {@code CONSTANT_DESCENT} the prevailing row for the panel is
 *   row 1.
 * <li>Two buttons, each with a baseline-resize behavior of
 *   {@code CENTER_OFFSET} and an anchor of {@code BASELINE}.
 * </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},
 * 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} 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}
 * 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.
 *
 * <table class="borderless" style="margin: 0px auto">
 * <caption style="width:600;display:none">Figures</caption>
 * <tr style="text-align:center">
 * <td>
 * <img src="doc-files/GridBagLayout-1.gif" alt="The preceding text describes this graphic (Figure 1)." style="float:center; margin: 7px 10px;">
 * </td>
 * <td>
 * <img src="doc-files/GridBagLayout-2.gif" alt="The preceding text describes this graphic (Figure 2)." style="float:center; margin: 7px 10px;">
 * </td>
 * <tr style="text-align:center">
 * <td>Figure 2: Horizontal, Left-to-Right</td>
 * <td>Figure 3: Horizontal, Right-to-Left</td>
 * </tr>
 * </table>
 * <p>
 * Each of the ten components has the {@code fill} field
 * of its associated {@code GridBagConstraints} object
 * set to {@code GridBagConstraints.BOTH}.
 * In addition, the components have the following non-default constraints:
 *
 * <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:
 *
 * <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>
 *
 * @author Doug Stein
 * @author Bill Spitzak (orignial NeWS &amp; OLIT implementation)
 * @see       java.awt.GridBagConstraints
 * @see       java.awt.GridBagLayoutInfo
 * @see       java.awt.ComponentOrientation
 * @since 1.0
 */
public class GridBagLayout implements LayoutManager2,
java.io.Serializable {

    static final int EMPIRICMULTIPLIER = 2;
    
This field is no longer used to reserve arrays and kept 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.

/**
     * This field is no longer used to reserve arrays and kept 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.

/**
     * 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.

/**
     * 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 comptable are the components and the values are the instances of GridBagConstraints. 
See Also:
@serial
/**
     * This hashtable maintains the association between
     * a component and its gridbag constraints.
     * The Keys in {@code comptable} are the components and the
     * values are the instances of {@code GridBagConstraints}.
     *
     * @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 defaultConstraints. 
See Also:
@serial
/**
     * 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}.
     *
     * @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 layoutInfo is null this indicates that there are no components in the gridbag or if there are components, they have not yet been validated. 
See Also:
@serial
/**
     * 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} is {@code null}
     * 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-null 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. 
See Also:
@serial
/**
     * This field holds the overrides to the column minimum
     * width.  If this field is non-{@code null} 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-null the values are applied to the gridbag after all of the minimum row heights have been calculated. If rowHeights has more elements than the number of rows, rows are added to the gridbag to match the number of elements in rowHeights. 
See Also:
@serial
/**
     * This field holds the overrides to the row minimum
     * heights.  If this field is non-{@code null} the values are
     * applied to the gridbag after all of the minimum row
     * heights have been calculated.
     * If {@code rowHeights} has more elements than the number of
     * rows, rows are added to the gridbag to match
     * the number of elements in {@code rowHeights}.
     *
     * @serial
     * @see #getLayoutDimensions()
     */
    public int rowHeights[];

    
This field holds the overrides to the column weights. If this field is non-null the values are applied to the gridbag after all of the columns weights have been calculated. If columnWeights[i] > weight for column i, then column i is assigned the weight in columnWeights[i]. If columnWeights has more elements than the number of columns, the excess elements are ignored - they do not cause more columns to be created. 
@serial
/**
     * This field holds the overrides to the column weights.
     * If this field is non-{@code null} the values are
     * applied to the gridbag after all of the columns
     * weights have been calculated.
     * If {@code columnWeights[i] >} weight for column i, then
     * column i is assigned the weight in {@code columnWeights[i]}.
     * If {@code columnWeights} 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-null the values are applied to the gridbag after all of the rows weights have been calculated. If rowWeights[i] >  weight for row i, then row i is assigned the weight in rowWeights[i]. If rowWeights has more elements than the number of rows, the excess elements are ignored - they do not cause more rows to be created. 
@serial
/**
     * This field holds the overrides to the row weights.
     * If this field is non-{@code null} the values are
     * applied to the gridbag after all of the rows
     * weights have been calculated.
     * If {@code rowWeights[i] > } weight for row i, then
     * row i is assigned the weight in {@code rowWeights[i]}.
     * If {@code rowWeights} 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 adjustForGravity. 
/**
     * The component being positioned.  This is set before calling into
     * {@code adjustForGravity}.
     */
    private Component componentAdjusting;

    
Creates a grid bag layout manager.

/**
     * 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.

Params:
  • comp – the component to be modified
  • constraints – the constraints to be applied
/**
     * 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 GridBagConstraints object is returned. 
Params:
  • comp – the component to be queried
Returns:     the constraint for the specified component in this
                 grid bag layout; a copy of the actual constraint
                 object is returned
/**
     * Gets the constraints for the specified component.  A copy of
     * the actual {@code GridBagConstraints} 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 GridBagConstraints object used by the layout mechanism. 
 If comp is not in the GridBagLayout, a set of default GridBagConstraints are returned. A comp value of null is invalid and returns null. 
Params:
  • comp – the component to be queried
Returns:     the constraints for the specified component
/**
     * Retrieves the constraints for the specified component.
     * The return value is not a copy, but is the actual
     * {@code GridBagConstraints} object used by the layout mechanism.
     * <p>
     * If {@code comp} is not in the {@code GridBagLayout},
     * a set of default {@code GridBagConstraints} are returned.
     * A {@code comp} value of {@code null} is invalid
     * and returns {@code null}.
     *
     * @param       comp the component to be queried
     * @return      the constraints 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

Params:
  • comp – the component to be modified
/**
     * 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 ComponentOrientation 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. 
See Also:
Returns:    the graphics origin of the cell in the top-left
            corner of the layout grid
Since:     1.1
/**
     * 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} 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      1.1
     */
    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.


Most applications do not call this method directly.

Returns:    an array of two arrays, containing the widths
                      of the layout columns and
                      the heights of the layout rows
Since:     1.1
/**
     * 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      1.1
     */
    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.


Most applications do not call this method directly.

Returns:     an array of two arrays, representing the
                   horizontal weights of the layout columns
                   and the vertical weights of the layout rows
Since:      1.1
/**
     * 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       1.1
     */
    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 (x, y). 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).


If the (x, y) point lies outside the grid, the following rules are used. The column index is returned as zero if x 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 x 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 y lies above the layout, and as the number of rows if y lies below the layout. The orientation of a container is determined by its ComponentOrientation property. 
Params:
  • x –    the x coordinate of a point
  • y –    the y coordinate of a point
See Also:
Returns:    an ordered pair of indexes that indicate which cell
            in the layout grid contains the point
            (x, y).
Since:     1.1
/**
     * 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} 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} 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} lies above the
     * layout, and as the number of rows if {@code y} lies
     * below the layout.  The orientation of a container is determined by its
     * {@code ComponentOrientation} 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      1.1
     */
    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.

/**
     * 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 constraints object. Note that constraints are mutable and are, therefore, cloned when cached. 
Params:
  • comp –         the component to be added
  • constraints –  an object that determines how
                         the component is added to the layout
Throws:
/**
     * Adds the specified component to the layout, using the specified
     * {@code constraints} 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}
     *            is not a {@code GridBagConstraint}
     */
    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.


Most applications do not call this method directly.

Params:
  • comp –   the component to be removed.
See Also:
/**
     * 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 parent container using this grid bag layout. 

Most applications do not call this method directly.

Params:
  • parent –   the container in which to do the layout
See Also:
Returns:the preferred size of the parent container
/**
     * Determines the preferred size of the {@code parent}
     * 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}
     *  container
     */
    public Dimension preferredLayoutSize(Container parent) {
        GridBagLayoutInfo info = getLayoutInfo(parent, PREFERREDSIZE);
        return getMinSize(parent, info);
    }

    
Determines the minimum size of the parent container using this grid bag layout. 

Most applications do not call this method directly.

Params:
  • parent –   the container in which to do the layout
See Also:
Returns:the minimum size of the parent container
/**
     * Determines the minimum size of the {@code parent} 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} 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.

Params:
  • target – the container which needs to be laid out
See Also:
Returns:the maximum dimensions for this layout
/**
     * 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.

Returns:the value 0.5f to indicate centered
/**
     * 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.
     *
     * @return the value {@code 0.5f} 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.

Returns:the value 0.5f to indicate centered
/**
     * 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.
     *
     * @return the value {@code 0.5f} 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.

/**
     * 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 constraints of this GridBagLayout object. 

Most applications do not call this method directly.

Params:
  • parent – the container in which to do the layout
See Also:
/**
     * Lays out the specified container using this grid bag layout.
     * This method reshapes components in the specified container in
     * order to satisfy the constraints of this {@code GridBagLayout}
     * 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.

Returns:    a string representation of this grid bag layout.
/**
     * 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 GridBagLayoutInfo for the current set of managed children. This requires three passes through the set of children: 
    

  1. Figure out the dimensions of the layout grid.

  2. Determine which cells the components occupy.

  3. Distribute the weights and min sizes among the rows/columns.


This also caches the minsizes for all the children when they are
first encountered (so subsequent loops don't need to ask again).

 This method should only be used internally by GridBagLayout. 
Params:
  • parent –  the layout container
  • sizeflag – either PREFERREDSIZE or MINSIZE
Returns:the GridBagLayoutInfo for the set of children
Since:1.4
/**
     * Fills in an instance of {@code GridBagLayoutInfo} 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 among 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}.
     *
     * @param parent  the layout container
     * @param sizeflag either {@code PREFERREDSIZE} or
     *   {@code MINSIZE}
     * @return the {@code GridBagLayoutInfo} 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 compatibility only; new code should call getLayoutInfo instead. Fills in an instance of GridBagLayoutInfo for the current set of managed children. This method is the same as getLayoutInfo; refer to getLayoutInfo description for details. 
Params:
  • parent – the layout container
  • sizeflag – either PREFERREDSIZE or MINSIZE
Returns:the GridBagLayoutInfo for the set of children
/**
     * This method is obsolete and supplied for backwards
     * compatibility only; new code should call {@link
     * #getLayoutInfo(java.awt.Container, int) getLayoutInfo} instead.
     *
     * Fills in an instance of {@code GridBagLayoutInfo} for the
     * current set of managed children. This method is the same
     * as {@code getLayoutInfo}; refer to {@code getLayoutInfo}
     * description for details.
     *
     * @param  parent the layout container
     * @param  sizeflag either {@code PREFERREDSIZE} or {@code MINSIZE}
     * @return the {@code GridBagLayoutInfo} for the set of children
     */
    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: unnecessary 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) {
                    case GridBagConstraints.BASELINE:
                    case GridBagConstraints.BASELINE_LEADING:
                    case GridBagConstraints.BASELINE_TRAILING:
                        if (constraints.ascent >= 0) {
                            if (curHeight == 1) {
                                maxAscent[curY] =
                                        Math.max(maxAscent[curY],
                                                 constraints.ascent);
                                maxDescent[curY] =
                                        Math.max(maxDescent[curY],
                                                 constraints.descent);
                            }
                            else {
                                if (constraints.baselineResizeBehavior ==
                                        Component.BaselineResizeBehavior.
                                        CONSTANT_DESCENT) {
                                    maxDescent[curY + curHeight - 1] =
                                        Math.max(maxDescent[curY + curHeight
                                                            - 1],
                                                 constraints.descent);
                                }
                                else {
                                    maxAscent[curY] = Math.max(maxAscent[curY],
                                                           constraints.ascent);
                                }
                            }
                            if (constraints.baselineResizeBehavior ==
                                    Component.BaselineResizeBehavior.CONSTANT_DESCENT) {
                                baselineType[curY + curHeight - 1] |=
                                        (1 << constraints.
                                         baselineResizeBehavior.ordinal());
                            }
                            else {
                                baselineType[curY] |= (1 << constraints.
                                             baselineResizeBehavior.ordinal());
                            }
                        }
                        break;
                    case GridBagConstraints.ABOVE_BASELINE:
                    case GridBagConstraints.ABOVE_BASELINE_LEADING:
                    case GridBagConstraints.ABOVE_BASELINE_TRAILING:
                        // Component positioned above the baseline.
                        // To make the bottom edge of the component aligned
                        // with the baseline the bottom inset is
                        // added to the descent, the rest to the ascent.
                        pixels_diff = constraints.minHeight +
                                constraints.insets.top +
                                constraints.ipady;
                        maxAscent[curY] = Math.max(maxAscent[curY],
                                                   pixels_diff);
                        maxDescent[curY] = Math.max(maxDescent[curY],
                                                    constraints.insets.bottom);
                        break;
                    case GridBagConstraints.BELOW_BASELINE:
                    case GridBagConstraints.BELOW_BASELINE_LEADING:
                    case GridBagConstraints.BELOW_BASELINE_TRAILING:
                        // Component positioned below the baseline.
                        // To make the top edge of the component aligned
                        // with the baseline the top inset is
                        // added to the ascent, the rest to the descent.
                        pixels_diff = constraints.minHeight +
                                constraints.insets.bottom + constraints.ipady;
                        maxDescent[curY] = Math.max(maxDescent[curY],
                                                    pixels_diff);
                        maxAscent[curY] = Math.max(maxAscent[curY],
                                                   constraints.insets.top);
                        break;
                    }
                }
            }

            r.weightX = new double[maximumArrayYIndex];
            r.weightY = new double[maximumArrayXIndex];
            r.minWidth = new int[maximumArrayYIndex];
            r.minHeight = new int[maximumArrayXIndex];


            /*
             * Apply minimum row/column dimensions and weights
             */
            if (columnWidths != null)
                System.arraycopy(columnWidths, 0, r.minWidth, 0, columnWidths.length);
            if (rowHeights != null)
                System.arraycopy(rowHeights, 0, r.minHeight, 0, rowHeights.length);
            if (columnWeights != null)
                System.arraycopy(columnWeights, 0, r.weightX, 0,  Math.min(r.weightX.length, columnWeights.length));
            if (rowWeights != null)
                System.arraycopy(rowWeights, 0, r.weightY, 0,  Math.min(r.weightY.length, rowWeights.length));

            /*
             * Pass #3
             *
             * Distribute the minimum widths and weights:
             */

            nextSize = Integer.MAX_VALUE;

            for (i = 1;
                 i != Integer.MAX_VALUE;
                 i = nextSize, nextSize = Integer.MAX_VALUE) {
                for (compindex = 0 ; compindex < components.length ; compindex++) {
                    comp = components[compindex];
                    if (!comp.isVisible())
                        continue;
                    constraints = lookupConstraints(comp);

                    if (constraints.tempWidth == i) {
                        px = constraints.tempX + constraints.tempWidth; /* right column */

                        /*
                         * Figure out if we should use this slave\'s weight.  If the weight
                         * is less than the total weight spanned by the width of the cell,
                         * then discard the weight.  Otherwise split the difference
                         * according to the existing weights.
                         */

                        weight_diff = constraints.weightx;
                        for (k = constraints.tempX; k < px; k++)
                            weight_diff -= r.weightX[k];
                        if (weight_diff > 0.0) {
                            weight = 0.0;
                            for (k = constraints.tempX; k < px; k++)
                                weight += r.weightX[k];
                            for (k = constraints.tempX; weight > 0.0 && k < px; k++) {
                                double wt = r.weightX[k];
                                double dx = (wt * weight_diff) / weight;
                                r.weightX[k] += dx;
                                weight_diff -= dx;
                                weight -= wt;
                            }
                            /* Assign the remainder to the rightmost cell */
                            r.weightX[px-1] += weight_diff;
                        }

                        /*
                         * Calculate the minWidth array values.
                         * First, figure out how wide the current slave needs to be.
                         * Then, see if it will fit within the current minWidth values.
                         * If it will not fit, add the difference according to the
                         * weightX array.
                         */

                        pixels_diff =
                            constraints.minWidth + constraints.ipadx +
                            constraints.insets.left + constraints.insets.right;

                        for (k = constraints.tempX; k < px; k++)
                            pixels_diff -= r.minWidth[k];
                        if (pixels_diff > 0) {
                            weight = 0.0;
                            for (k = constraints.tempX; k < px; k++)
                                weight += r.weightX[k];
                            for (k = constraints.tempX; weight > 0.0 && k < px; k++) {
                                double wt = r.weightX[k];
                                int dx = (int)((wt * ((double)pixels_diff)) / weight);
                                r.minWidth[k] += dx;
                                pixels_diff -= dx;
                                weight -= wt;
                            }
                            /* Any leftovers go into the rightmost cell */
                            r.minWidth[px-1] += pixels_diff;
                        }
                    }
                    else if (constraints.tempWidth > i && constraints.tempWidth < nextSize)
                        nextSize = constraints.tempWidth;


                    if (constraints.tempHeight == i) {
                        py = constraints.tempY + constraints.tempHeight; /* bottom row */

                        /*
                         * Figure out if we should use this slave's weight.  If the weight
                         * is less than the total weight spanned by the height of the cell,
                         * then discard the weight.  Otherwise split it the difference
                         * according to the existing weights.
                         */

                        weight_diff = constraints.weighty;
                        for (k = constraints.tempY; k < py; k++)
                            weight_diff -= r.weightY[k];
                        if (weight_diff > 0.0) {
                            weight = 0.0;
                            for (k = constraints.tempY; k < py; k++)
                                weight += r.weightY[k];
                            for (k = constraints.tempY; weight > 0.0 && k < py; k++) {
                                double wt = r.weightY[k];
                                double dy = (wt * weight_diff) / weight;
                                r.weightY[k] += dy;
                                weight_diff -= dy;
                                weight -= wt;
                            }
                            /* Assign the remainder to the bottom cell */
                            r.weightY[py-1] += weight_diff;
                        }

                        /*
                         * Calculate the minHeight array values.
                         * First, figure out how tall the current slave needs to be.
                         * Then, see if it will fit within the current minHeight values.
                         * If it will not fit, add the difference according to the
                         * weightY array.
                         */

                        pixels_diff = -1;
                        if (hasBaseline) {
                            switch(constraints.anchor) {
                            case GridBagConstraints.BASELINE:
                            case GridBagConstraints.BASELINE_LEADING:
                            case GridBagConstraints.BASELINE_TRAILING:
                                if (constraints.ascent >= 0) {
                                    if (constraints.tempHeight == 1) {
                                        pixels_diff =
                                            maxAscent[constraints.tempY] +
                                            maxDescent[constraints.tempY];
                                    }
                                    else if (constraints.baselineResizeBehavior !=
                                             Component.BaselineResizeBehavior.
                                             CONSTANT_DESCENT) {
                                        pixels_diff =
                                                maxAscent[constraints.tempY] +
                                                constraints.descent;
                                    }
                                    else {
                                        pixels_diff = constraints.ascent +
                                                maxDescent[constraints.tempY +
                                                   constraints.tempHeight - 1];
                                    }
                                }
                                break;
                            case GridBagConstraints.ABOVE_BASELINE:
                            case GridBagConstraints.ABOVE_BASELINE_LEADING:
                            case GridBagConstraints.ABOVE_BASELINE_TRAILING:
                                pixels_diff = constraints.insets.top +
                                        constraints.minHeight +
                                        constraints.ipady +
                                        maxDescent[constraints.tempY];
                                break;
                            case GridBagConstraints.BELOW_BASELINE:
                            case GridBagConstraints.BELOW_BASELINE_LEADING:
                            case GridBagConstraints.BELOW_BASELINE_TRAILING:
                                pixels_diff = maxAscent[constraints.tempY] +
                                        constraints.minHeight +
                                        constraints.insets.bottom +
                                        constraints.ipady;
                                break;
                            }
                        }
                        if (pixels_diff == -1) {
                            pixels_diff =
                                constraints.minHeight + constraints.ipady +
                                constraints.insets.top +
                                constraints.insets.bottom;
                        }
                        for (k = constraints.tempY; k < py; k++)
                            pixels_diff -= r.minHeight[k];
                        if (pixels_diff > 0) {
                            weight = 0.0;
                            for (k = constraints.tempY; k < py; k++)
                                weight += r.weightY[k];
                            for (k = constraints.tempY; weight > 0.0 && k < py; k++) {
                                double wt = r.weightY[k];
                                int dy = (int)((wt * ((double)pixels_diff)) / weight);
                                r.minHeight[k] += dy;
                                pixels_diff -= dy;
                                weight -= wt;
                            }
                            /* Any leftovers go into the bottom cell */
                            r.minHeight[py-1] += pixels_diff;
                        }
                    }
                    else if (constraints.tempHeight > i &&
                             constraints.tempHeight < nextSize)
                        nextSize = constraints.tempHeight;
                }
            }
            return r;
        }
    } //getLayoutInfo()

    
Calculate the baseline for the specified component. If c is positioned along it's baseline, the baseline is obtained and the constraints ascent, descent and baseline resize behavior are set from the component; and true is returned. Otherwise false is returned. 
/**
     * Calculate the baseline for the specified component.
     * If {@code c} is positioned along it's baseline, the baseline is
     * obtained and the {@code constraints} ascent, descent and
     * baseline resize behavior are set from the component; and true is
     * returned. Otherwise false is returned.
     */
    private boolean calculateBaseline(Component c,
                                      GridBagConstraints constraints,
                                      Dimension size) {
        int anchor = constraints.anchor;
        if (anchor == GridBagConstraints.BASELINE ||
                anchor == GridBagConstraints.BASELINE_LEADING ||
                anchor == GridBagConstraints.BASELINE_TRAILING) {
            // Apply the padding to the component, then ask for the baseline.
            int w = size.width + constraints.ipadx;
            int h = size.height + constraints.ipady;
            constraints.ascent = c.getBaseline(w, h);
            if (constraints.ascent >= 0) {
                // Component has a baseline
                int baseline = constraints.ascent;
                // Adjust the ascent and descent to include the insets.
                constraints.descent = h - constraints.ascent +
                            constraints.insets.bottom;
                constraints.ascent += constraints.insets.top;
                constraints.baselineResizeBehavior =
                        c.getBaselineResizeBehavior();
                constraints.centerPadding = 0;
                if (constraints.baselineResizeBehavior == Component.
                        BaselineResizeBehavior.CENTER_OFFSET) {
                    // Component has a baseline resize behavior of
                    // CENTER_OFFSET, calculate centerPadding and
                    // centerOffset (see the description of
                    // CENTER_OFFSET in the enum for details on this
                    // algorithm).
                    int nextBaseline = c.getBaseline(w, h + 1);
                    constraints.centerOffset = baseline - h / 2;
                    if (h % 2 == 0) {
                        if (baseline != nextBaseline) {
                            constraints.centerPadding = 1;
                        }
                    }
                    else if (baseline == nextBaseline){
                        constraints.centerOffset--;
                        constraints.centerPadding = 1;
                    }
                }
            }
            return true;
        }
        else {
            constraints.ascent = -1;
            return false;
        }
    }

    
Adjusts the x, y, width, and height fields to the correct values depending on the constraint geometry and pads. This method should only be used internally by GridBagLayout. 
Params:
  • constraints – the constraints to be applied
  • r – the Rectangle to be adjusted
Since:1.4
/**
     * Adjusts the x, y, width, and height fields to the correct
     * values depending on the constraint geometry and pads.
     * This method should only be used internally by
     * {@code GridBagLayout}.
     *
     * @param constraints the constraints to be applied
     * @param r the {@code Rectangle} to be adjusted
     * @since 1.4
     */
    protected void adjustForGravity(GridBagConstraints constraints,
                                    Rectangle r) {
        AdjustForGravity(constraints, r);
    }

    
Adjusts the x, y, width, and height fields to the correct
values depending on the constraint geometry and pads.

 This method is obsolete and supplied for backwards compatibility only; new code should call 
adjustForGravity instead. This method is the same as adjustForGravity 
Params:
  • constraints – the constraints to be applied
  • r – the Rectangle to be adjusted
/**
     * Adjusts the x, y, width, and height fields to the correct
     * values depending on the constraint geometry and pads.
     * <p>
     * This method is obsolete and supplied for backwards
     * compatibility only; new code should call {@link
     * #adjustForGravity(java.awt.GridBagConstraints, java.awt.Rectangle)
     * adjustForGravity} instead.
     * This method is the same as {@code adjustForGravity}
     *
     * @param  constraints the constraints to be applied
     * @param  r the {@code Rectangle} to be adjusted
     */
    protected void AdjustForGravity(GridBagConstraints constraints,
                                    Rectangle r) {
        int diffx, diffy;
        int cellY = r.y;
        int cellHeight = r.height;

        if (!rightToLeft) {
            r.x += constraints.insets.left;
        } else {
            r.x -= r.width - constraints.insets.right;
        }
        r.width -= (constraints.insets.left + constraints.insets.right);
        r.y += constraints.insets.top;
        r.height -= (constraints.insets.top + constraints.insets.bottom);

        diffx = 0;
        if ((constraints.fill != GridBagConstraints.HORIZONTAL &&
             constraints.fill != GridBagConstraints.BOTH)
            && (r.width > (constraints.minWidth + constraints.ipadx))) {
            diffx = r.width - (constraints.minWidth + constraints.ipadx);
            r.width = constraints.minWidth + constraints.ipadx;
        }

        diffy = 0;
        if ((constraints.fill != GridBagConstraints.VERTICAL &&
             constraints.fill != GridBagConstraints.BOTH)
            && (r.height > (constraints.minHeight + constraints.ipady))) {
            diffy = r.height - (constraints.minHeight + constraints.ipady);
            r.height = constraints.minHeight + constraints.ipady;
        }

        switch (constraints.anchor) {
          case GridBagConstraints.BASELINE:
              r.x += diffx/2;
              alignOnBaseline(constraints, r, cellY, cellHeight);
              break;
          case GridBagConstraints.BASELINE_LEADING:
              if (rightToLeft) {
                  r.x += diffx;
              }
              alignOnBaseline(constraints, r, cellY, cellHeight);
              break;
          case GridBagConstraints.BASELINE_TRAILING:
              if (!rightToLeft) {
                  r.x += diffx;
              }
              alignOnBaseline(constraints, r, cellY, cellHeight);
              break;
          case GridBagConstraints.ABOVE_BASELINE:
              r.x += diffx/2;
              alignAboveBaseline(constraints, r, cellY, cellHeight);
              break;
          case GridBagConstraints.ABOVE_BASELINE_LEADING:
              if (rightToLeft) {
                  r.x += diffx;
              }
              alignAboveBaseline(constraints, r, cellY, cellHeight);
              break;
          case GridBagConstraints.ABOVE_BASELINE_TRAILING:
              if (!rightToLeft) {
                  r.x += diffx;
              }
              alignAboveBaseline(constraints, r, cellY, cellHeight);
              break;
          case GridBagConstraints.BELOW_BASELINE:
              r.x += diffx/2;
              alignBelowBaseline(constraints, r, cellY, cellHeight);
              break;
          case GridBagConstraints.BELOW_BASELINE_LEADING:
              if (rightToLeft) {
                  r.x += diffx;
              }
              alignBelowBaseline(constraints, r, cellY, cellHeight);
              break;
          case GridBagConstraints.BELOW_BASELINE_TRAILING:
              if (!rightToLeft) {
                  r.x += diffx;
              }
              alignBelowBaseline(constraints, r, cellY, cellHeight);
              break;
          case GridBagConstraints.CENTER:
              r.x += diffx/2;
              r.y += diffy/2;
              break;
          case GridBagConstraints.PAGE_START:
          case GridBagConstraints.NORTH:
              r.x += diffx/2;
              break;
          case GridBagConstraints.NORTHEAST:
              r.x += diffx;
              break;
          case GridBagConstraints.EAST:
              r.x += diffx;
              r.y += diffy/2;
              break;
          case GridBagConstraints.SOUTHEAST:
              r.x += diffx;
              r.y += diffy;
              break;
          case GridBagConstraints.PAGE_END:
          case GridBagConstraints.SOUTH:
              r.x += diffx/2;
              r.y += diffy;
              break;
          case GridBagConstraints.SOUTHWEST:
              r.y += diffy;
              break;
          case GridBagConstraints.WEST:
              r.y += diffy/2;
              break;
          case GridBagConstraints.NORTHWEST:
              break;
          case GridBagConstraints.LINE_START:
              if (rightToLeft) {
                  r.x += diffx;
              }
              r.y += diffy/2;
              break;
          case GridBagConstraints.LINE_END:
              if (!rightToLeft) {
                  r.x += diffx;
              }
              r.y += diffy/2;
              break;
          case GridBagConstraints.FIRST_LINE_START:
              if (rightToLeft) {
                  r.x += diffx;
              }
              break;
          case GridBagConstraints.FIRST_LINE_END:
              if (!rightToLeft) {
                  r.x += diffx;
              }
              break;
          case GridBagConstraints.LAST_LINE_START:
              if (rightToLeft) {
                  r.x += diffx;
              }
              r.y += diffy;
              break;
          case GridBagConstraints.LAST_LINE_END:
              if (!rightToLeft) {
                  r.x += diffx;
              }
              r.y += diffy;
              break;
          default:
              throw new IllegalArgumentException("illegal anchor value");
        }
    }

    
Positions on the baseline.

Params:
  • cellY – the location of the row, does not include insets
  • cellHeight – the height of the row, does not take into account
       insets
  • r – available bounds for the component, is padded by insets and
       ipady
/**
     * Positions on the baseline.
     *
     * @param cellY the location of the row, does not include insets
     * @param cellHeight the height of the row, does not take into account
     *        insets
     * @param r available bounds for the component, is padded by insets and
     *        ipady
     */
    private void alignOnBaseline(GridBagConstraints cons, Rectangle r,
                                 int cellY, int cellHeight) {
        if (cons.ascent >= 0) {
            if (cons.baselineResizeBehavior == Component.
                    BaselineResizeBehavior.CONSTANT_DESCENT) {
                // Anchor to the bottom.
                // Baseline is at (cellY + cellHeight - maxDescent).
                // Bottom of component (maxY) is at baseline + descent
                // of component. We need to subtract the bottom inset here
                // as the descent in the constraints object includes the
                // bottom inset.
                int maxY = cellY + cellHeight -
                      layoutInfo.maxDescent[cons.tempY + cons.tempHeight - 1] +
                      cons.descent - cons.insets.bottom;
                if (!cons.isVerticallyResizable()) {
                    // Component not resizable, calculate y location
                    // from maxY - height.
                    r.y = maxY - cons.minHeight;
                    r.height = cons.minHeight;
                } else {
                    // Component is resizable. As brb is constant descent,
                    // can expand component to fill region above baseline.
                    // Subtract out the top inset so that components insets
                    // are honored.
                    r.height = maxY - cellY - cons.insets.top;
                }
            }
            else {
                // BRB is not constant_descent
                int baseline; // baseline for the row, relative to cellY
                // Component baseline, includes insets.top
                int ascent = cons.ascent;
                if (layoutInfo.hasConstantDescent(cons.tempY)) {
                    // Mixed ascent/descent in same row, calculate position
                    // off maxDescent
                    baseline = cellHeight - layoutInfo.maxDescent[cons.tempY];
                }
                else {
                    // Only ascents/unknown in this row, anchor to top
                    baseline = layoutInfo.maxAscent[cons.tempY];
                }
                if (cons.baselineResizeBehavior == Component.
                        BaselineResizeBehavior.OTHER) {
                    // BRB is other, which means we can only determine
                    // the baseline by asking for it again giving the
                    // size we plan on using for the component.
                    boolean fits = false;
                    ascent = componentAdjusting.getBaseline(r.width, r.height);
                    if (ascent >= 0) {
                        // Component has a baseline, pad with top inset
                        // (this follows from calculateBaseline which
                        // does the same).
                        ascent += cons.insets.top;
                    }
                    if (ascent >= 0 && ascent <= baseline) {
                        // Components baseline fits within rows baseline.
                        // Make sure the descent fits within the space as well.
                        if (baseline + (r.height - ascent - cons.insets.top) <=
                                cellHeight - cons.insets.bottom) {
                            // It fits, we're good.
                            fits = true;
                        }
                        else if (cons.isVerticallyResizable()) {
                            // Doesn't fit, but it's resizable.  Try
                            // again assuming we'll get ascent again.
                            int ascent2 = componentAdjusting.getBaseline(
                                    r.width, cellHeight - cons.insets.bottom -
                                    baseline + ascent);
                            if (ascent2 >= 0) {
                                ascent2 += cons.insets.top;
                            }
                            if (ascent2 >= 0 && ascent2 <= ascent) {
                                // It'll fit
                                r.height = cellHeight - cons.insets.bottom -
                                        baseline + ascent;
                                ascent = ascent2;
                                fits = true;
                            }
                        }
                    }
                    if (!fits) {
                        // Doesn't fit, use min size and original ascent
                        ascent = cons.ascent;
                        r.width = cons.minWidth;
                        r.height = cons.minHeight;
                    }
                }
                // Reset the components y location based on
                // components ascent and baseline for row. Because ascent
                // includes the baseline
                r.y = cellY + baseline - ascent + cons.insets.top;
                if (cons.isVerticallyResizable()) {
                    switch(cons.baselineResizeBehavior) {
                    case CONSTANT_ASCENT:
                        r.height = Math.max(cons.minHeight,cellY + cellHeight -
                                            r.y - cons.insets.bottom);
                        break;
                    case CENTER_OFFSET:
                        {
                            int upper = r.y - cellY - cons.insets.top;
                            int lower = cellY + cellHeight - r.y -
                                cons.minHeight - cons.insets.bottom;
                            int delta = Math.min(upper, lower);
                            delta += delta;
                            if (delta > 0 &&
                                (cons.minHeight + cons.centerPadding +
                                 delta) / 2 + cons.centerOffset != baseline) {
                                // Off by 1
                                delta--;
                            }
                            r.height = cons.minHeight + delta;
                            r.y = cellY + baseline -
                                (r.height + cons.centerPadding) / 2 -
                                cons.centerOffset;
                        }
                        break;
                    case OTHER:
                        // Handled above
                        break;
                    default:
                        break;
                    }
                }
            }
        }
        else {
            centerVertically(cons, r, cellHeight);
        }
    }

    
Positions the specified component above the baseline. That is
the bottom edge of the component will be aligned along the baseline.
If the row does not have a baseline, this centers the component.

/**
     * Positions the specified component above the baseline. That is
     * the bottom edge of the component will be aligned along the baseline.
     * If the row does not have a baseline, this centers the component.
     */
    private void alignAboveBaseline(GridBagConstraints cons, Rectangle r,
                                    int cellY, int cellHeight) {
        if (layoutInfo.hasBaseline(cons.tempY)) {
            int maxY; // Baseline for the row
            if (layoutInfo.hasConstantDescent(cons.tempY)) {
                // Prefer descent
                maxY = cellY + cellHeight - layoutInfo.maxDescent[cons.tempY];
            }
            else {
                // Prefer ascent
                maxY = cellY + layoutInfo.maxAscent[cons.tempY];
            }
            if (cons.isVerticallyResizable()) {
                // Component is resizable. Top edge is offset by top
                // inset, bottom edge on baseline.
                r.y = cellY + cons.insets.top;
                r.height = maxY - r.y;
            }
            else {
                // Not resizable.
                r.height = cons.minHeight + cons.ipady;
                r.y = maxY - r.height;
            }
        }
        else {
            centerVertically(cons, r, cellHeight);
        }
    }

    
Positions below the baseline.

/**
     * Positions below the baseline.
     */
    private void alignBelowBaseline(GridBagConstraints cons, Rectangle r,
                                    int cellY, int cellHeight) {
        if (layoutInfo.hasBaseline(cons.tempY)) {
            if (layoutInfo.hasConstantDescent(cons.tempY)) {
                // Prefer descent
                r.y = cellY + cellHeight - layoutInfo.maxDescent[cons.tempY];
            }
            else {
                // Prefer ascent
                r.y = cellY + layoutInfo.maxAscent[cons.tempY];
            }
            if (cons.isVerticallyResizable()) {
                r.height = cellY + cellHeight - r.y - cons.insets.bottom;
            }
        }
        else {
            centerVertically(cons, r, cellHeight);
        }
    }

    private void centerVertically(GridBagConstraints cons, Rectangle r,
                                  int cellHeight) {
        if (!cons.isVerticallyResizable()) {
            r.y += Math.max(0, (cellHeight - cons.insets.top -
                                cons.insets.bottom - cons.minHeight -
                                cons.ipady) / 2);
        }
    }

    
Figures out the minimum size of the master based on the information from getLayoutInfo. This method should only be used internally by GridBagLayout. 
Params:
  • parent – the layout container
  • info – the layout info for this parent
Returns:a Dimension object containing the minimum size
Since:1.4
/**
     * Figures out the minimum size of the
     * master based on the information from {@code getLayoutInfo}.
     * This method should only be used internally by
     * {@code GridBagLayout}.
     *
     * @param parent the layout container
     * @param info the layout info for this parent
     * @return a {@code Dimension} object containing the
     *   minimum size
     * @since 1.4
     */
    protected Dimension getMinSize(Container parent, GridBagLayoutInfo info) {
        return GetMinSize(parent, info);
    }

    
This method is obsolete and supplied for backwards compatibility only; new code should call getMinSize instead. This method is the same as getMinSize 
Params:
  • parent – the layout container
  • info – the layout info for this parent
Returns:a Dimension object containing the minimum size
/**
     * This method is obsolete and supplied for backwards
     * compatibility only; new code should call {@link
     * #getMinSize(java.awt.Container, GridBagLayoutInfo) getMinSize} instead.
     * This method is the same as {@code getMinSize}
     *
     * @param  parent the layout container
     * @param  info the layout info for this parent
     * @return a {@code Dimension} object containing the
     *         minimum size
     */
    protected Dimension GetMinSize(Container parent, GridBagLayoutInfo info) {
        Dimension d = new Dimension();
        int i, t;
        Insets insets = parent.getInsets();

        t = 0;
        for(i = 0; i < info.width; i++)
            t += info.minWidth[i];
        d.width = t + insets.left + insets.right;

        t = 0;
        for(i = 0; i < info.height; i++)
            t += info.minHeight[i];
        d.height = t + insets.top + insets.bottom;

        return d;
    }

    transient boolean rightToLeft = false;

    
Lays out the grid. This method should only be used internally by GridBagLayout. 
Params:
  • parent – the layout container
Since:1.4
/**
     * Lays out the grid.
     * This method should only be used internally by
     * {@code GridBagLayout}.
     *
     * @param parent the layout container
     * @since 1.4
     */
    protected void arrangeGrid(Container parent) {
        ArrangeGrid(parent);
    }

    
This method is obsolete and supplied for backwards compatibility only; new code should call arrangeGrid instead. This method is the same as arrangeGrid 
Params:
  • parent – the layout container
/**
     * This method is obsolete and supplied for backwards
     * compatibility only; new code should call {@link
     * #arrangeGrid(Container) arrangeGrid} instead.
     * This method is the same as {@code arrangeGrid}
     *
     * @param  parent the layout container
     */
    protected void ArrangeGrid(Container parent) {
        Component comp;
        int compindex;
        GridBagConstraints constraints;
        Insets insets = parent.getInsets();
        Component components[] = parent.getComponents();
        Dimension d;
        Rectangle r = new Rectangle();
        int i, diffw, diffh;
        double weight;
        GridBagLayoutInfo info;

        rightToLeft = !parent.getComponentOrientation().isLeftToRight();

        /*
         * If the parent has no slaves anymore, then don't do anything
         * at all:  just leave the parent's size as-is.
         */
        if (components.length == 0 &&
            (columnWidths == null || columnWidths.length == 0) &&
            (rowHeights == null || rowHeights.length == 0)) {
            return;
        }

        /*
         * Pass #1: scan all the slaves to figure out the total amount
         * of space needed.
         */

        info = getLayoutInfo(parent, PREFERREDSIZE);
        d = getMinSize(parent, info);

        if (parent.width < d.width || parent.height < d.height) {
            info = getLayoutInfo(parent, MINSIZE);
            d = getMinSize(parent, info);
        }

        layoutInfo = info;
        r.width = d.width;
        r.height = d.height;

        /*
         * DEBUG
         *
         * DumpLayoutInfo(info);
         * for (compindex = 0 ; compindex < components.length ; compindex++) {
         * comp = components[compindex];
         * if (!comp.isVisible())
         *      continue;
         * constraints = lookupConstraints(comp);
         * DumpConstraints(constraints);
         * }
         * System.out.println("minSize " + r.width + " " + r.height);
         */

        /*
         * If the current dimensions of the window don't match the desired
         * dimensions, then adjust the minWidth and minHeight arrays
         * according to the weights.
         */

        diffw = parent.width - r.width;
        if (diffw != 0) {
            weight = 0.0;
            for (i = 0; i < info.width; i++)
                weight += info.weightX[i];
            if (weight > 0.0) {
                for (i = 0; i < info.width; i++) {
                    int dx = (int)(( ((double)diffw) * info.weightX[i]) / weight);
                    info.minWidth[i] += dx;
                    r.width += dx;
                    if (info.minWidth[i] < 0) {
                        r.width -= info.minWidth[i];
                        info.minWidth[i] = 0;
                    }
                }
            }
            diffw = parent.width - r.width;
        }

        else {
            diffw = 0;
        }

        diffh = parent.height - r.height;
        if (diffh != 0) {
            weight = 0.0;
            for (i = 0; i < info.height; i++)
                weight += info.weightY[i];
            if (weight > 0.0) {
                for (i = 0; i < info.height; i++) {
                    int dy = (int)(( ((double)diffh) * info.weightY[i]) / weight);
                    info.minHeight[i] += dy;
                    r.height += dy;
                    if (info.minHeight[i] < 0) {
                        r.height -= info.minHeight[i];
                        info.minHeight[i] = 0;
                    }
                }
            }
            diffh = parent.height - r.height;
        }

        else {
            diffh = 0;
        }

        /*
         * DEBUG
         *
         * System.out.println("Re-adjusted:");
         * DumpLayoutInfo(info);
         */

        /*
         * Now do the actual layout of the slaves using the layout information
         * that has been collected.
         */

        info.startx = diffw/2 + insets.left;
        info.starty = diffh/2 + insets.top;

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

            if (!rightToLeft) {
                r.x = info.startx;
                for(i = 0; i < constraints.tempX; i++)
                    r.x += info.minWidth[i];
            } else {
                r.x = parent.width - (diffw/2 + insets.right);
                for(i = 0; i < constraints.tempX; i++)
                    r.x -= info.minWidth[i];
            }

            r.y = info.starty;
            for(i = 0; i < constraints.tempY; i++)
                r.y += info.minHeight[i];

            r.width = 0;
            for(i = constraints.tempX;
                i < (constraints.tempX + constraints.tempWidth);
                i++) {
                r.width += info.minWidth[i];
            }

            r.height = 0;
            for(i = constraints.tempY;
                i < (constraints.tempY + constraints.tempHeight);
                i++) {
                r.height += info.minHeight[i];
            }

            componentAdjusting = comp;
            adjustForGravity(constraints, r);

            /* fix for 4408108 - components were being created outside of the container */
            /* fix for 4969409 "-" replaced by "+"  */
            if (r.x < 0) {
                r.width += r.x;
                r.x = 0;
            }

            if (r.y < 0) {
                r.height += r.y;
                r.y = 0;
            }

            /*
             * If the window is too small to be interesting then
             * unmap it.  Otherwise configure it and then make sure
             * it's mapped.
             */

            if ((r.width <= 0) || (r.height <= 0)) {
                comp.setBounds(0, 0, 0, 0);
            }
            else {
                if (comp.x != r.x || comp.y != r.y ||
                    comp.width != r.width || comp.height != r.height) {
                    comp.setBounds(r.x, r.y, r.width, r.height);
                }
            }
        }
    }

    // Added for serial backwards compatibility (4348425)
    static final long serialVersionUID = 8838754796412211005L;
}