SpringLayout Utilities : SpringLayout « Swing « Java Tutorial






/*
 * (c) Copyright 2004 by Heng Yuan
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * ITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

import java.awt.*;
import javax.swing.*;

/**
 * This code is from <a href="http://java.sun.com/docs/books/tutorial/index.html">Java Tutorial</a>
 * The source is at http://java.sun.com/docs/books/tutorial/uiswing/layout/example-1dot4/SpringUtilities.java.
 * No copyright or license information was in the source file and it was from the tutorial.  Thus
 * assuming I could use it in this program.  Below is the original file header.  The file is
 * not modified other than reformating white spaces.
 * <p>
 * A 1.4 file that provides utility methods for
 * creating form- or grid-style layouts with SpringLayout.
 * These utilities are used by several programs, such as
 * SpringBox and SpringCompactGrid.
 * </p>
 * TODO: Although algorithm wise is correct, this class fails to address the problem of rounding
 * errors.  As the result, sometimes the last row can be mismatched with other rows.  The solution
 * to the problem is to force the alignment of edges.
 *
 * @see javax.swing.SpringLayout
 * @see cookxml.cookswing.creator.SpringGridCreator
 * @author Heng Yuan
 * @version $Id: SpringLayoutUtilities.java 215 2007-06-06 03:59:41Z coconut $
 * @since CookSwing 1.0
 */
public class SpringLayoutUtilities
{
  /**
   * A debugging utility that prints to stdout the component's
   * minimum, preferred, and maximum sizes.
   */
  public static void printSizes (Component c)
  {
    System.out.println ("minimumSize = " + c.getMinimumSize ());
    System.out.println ("preferredSize = " + c.getPreferredSize ());
    System.out.println ("maximumSize = " + c.getMaximumSize ());
  }

  /**
   * Aligns the first <code>rows</code> * <code>cols</code>
   * components of <code>parent</code> in
   * a grid. Each component is as big as the maximum
   * preferred width and height of the components.
   * The parent is made just big enough to fit them all.
   *
   * @param rows     number of rows
   * @param cols     number of columns
   * @param initialX x location to start the grid at
   * @param initialY y location to start the grid at
   * @param xPad     x padding between cells
   * @param yPad     y padding between cells
   */
  public static void makeGrid (Container parent,
                 int rows, int cols,
                 int initialX, int initialY,
                 int xPad, int yPad)
  {
    SpringLayout layout;
    try
    {
      layout = (SpringLayout)parent.getLayout ();
    }
    catch (ClassCastException exc)
    {
      System.err.println ("The first argument to makeGrid must use SpringLayout.");
      return;
    }

    Spring xPadSpring = Spring.constant (xPad);
    Spring yPadSpring = Spring.constant (yPad);
    Spring initialXSpring = Spring.constant (initialX);
    Spring initialYSpring = Spring.constant (initialY);
    int max = rows * cols;

    //Calculate Springs that are the max of the width/height so that all
    //cells have the same size.
    Spring maxWidthSpring = layout.getConstraints (parent.getComponent (0)).
        getWidth ();
    Spring maxHeightSpring = layout.getConstraints (parent.getComponent (0)).
        getWidth ();
    for (int i = 1; i < max; i++)
    {
      SpringLayout.Constraints cons = layout.getConstraints (parent.getComponent (i));

      maxWidthSpring = Spring.max (maxWidthSpring, cons.getWidth ());
      maxHeightSpring = Spring.max (maxHeightSpring, cons.getHeight ());
    }

    //Apply the new width/height Spring. This forces all the
    //components to have the same size.
    for (int i = 0; i < max; i++)
    {
      SpringLayout.Constraints cons = layout.getConstraints (parent.getComponent (i));

      cons.setWidth (maxWidthSpring);
      cons.setHeight (maxHeightSpring);
    }

    //Then adjust the x/y constraints of all the cells so that they
    //are aligned in a grid.
    SpringLayout.Constraints lastCons = null;
    SpringLayout.Constraints lastRowCons = null;
    for (int i = 0; i < max; i++)
    {
      SpringLayout.Constraints cons = layout.getConstraints (parent.getComponent (i));
      if (i % cols == 0)
      { //start of new row
        lastRowCons = lastCons;
        cons.setX (initialXSpring);
      }
      else
      { //x position depends on previous component
        cons.setX (Spring.sum (lastCons.getConstraint (SpringLayout.EAST),
                     xPadSpring));
      }

      if (i / cols == 0)
      { //first row
        cons.setY (initialYSpring);
      }
      else
      { //y position depends on previous row
        cons.setY (Spring.sum (lastRowCons.getConstraint (SpringLayout.SOUTH),
                     yPadSpring));
      }
      lastCons = cons;
    }

    //Set the parent's size.
    SpringLayout.Constraints pCons = layout.getConstraints (parent);
    pCons.setConstraint (SpringLayout.SOUTH,
               Spring.sum (Spring.constant (yPad),
                     lastCons.getConstraint (SpringLayout.SOUTH)));
    pCons.setConstraint (SpringLayout.EAST,
               Spring.sum (Spring.constant (xPad),
                     lastCons.getConstraint (SpringLayout.EAST)));
  }

  /* Used by makeCompactGrid. */
  private static SpringLayout.Constraints getConstraintsForCell (int row, int col,
                                   Container parent,
                                   int cols)
  {
    SpringLayout layout = (SpringLayout)parent.getLayout ();
    Component c = parent.getComponent (row * cols + col);
    return layout.getConstraints (c);
  }

  /**
   * Aligns the first <code>rows</code> * <code>cols</code>
   * components of <code>parent</code> in
   * a grid. Each component in a column is as wide as the maximum
   * preferred width of the components in that column;
   * height is similarly determined for each row.
   * The parent is made just big enough to fit them all.
   *
   * @param rows     number of rows
   * @param cols     number of columns
   * @param initialX x location to start the grid at
   * @param initialY y location to start the grid at
   * @param xPad     x padding between cells
   * @param yPad     y padding between cells
   */
  public static void makeCompactGrid (Container parent,
                    int rows, int cols,
                    int initialX, int initialY,
                    int xPad, int yPad)
  {
    SpringLayout layout;
    try
    {
      layout = (SpringLayout)parent.getLayout ();
    }
    catch (ClassCastException exc)
    {
      System.err.println ("The first argument to makeCompactGrid must use SpringLayout.");
      return;
    }

    //Align all cells in each column and make them the same width.
    Spring x = Spring.constant (initialX);
    for (int c = 0; c < cols; c++)
    {
      Spring width = Spring.constant (0);
      for (int r = 0; r < rows; r++)
      {
        width = Spring.max (width,
                  getConstraintsForCell (r, c, parent, cols).
                  getWidth ());
      }
      for (int r = 0; r < rows; r++)
      {
        SpringLayout.Constraints constraints =
            getConstraintsForCell (r, c, parent, cols);
        constraints.setX (x);
        constraints.setWidth (width);
      }
      x = Spring.sum (x, Spring.sum (width, Spring.constant (xPad)));
    }

    //Align all cells in each row and make them the same height.
    Spring y = Spring.constant (initialY);
    for (int r = 0; r < rows; r++)
    {
      Spring height = Spring.constant (0);
      for (int c = 0; c < cols; c++)
      {
        height = Spring.max (height,
                   getConstraintsForCell (r, c, parent, cols).
                   getHeight ());
      }
      for (int c = 0; c < cols; c++)
      {
        SpringLayout.Constraints constraints =
            getConstraintsForCell (r, c, parent, cols);
        constraints.setY (y);
        constraints.setHeight (height);
      }
      y = Spring.sum (y, Spring.sum (height, Spring.constant (yPad)));
    }

    //Set the parent's size.
    SpringLayout.Constraints pCons = layout.getConstraints (parent);
    pCons.setConstraint (SpringLayout.SOUTH, y);
    pCons.setConstraint (SpringLayout.EAST, x);
  }
}








14.92.SpringLayout
14.92.1.SpringLayoutSpringLayout
14.92.2.How to Use SpringLayoutHow to Use SpringLayout
14.92.3.Specifying locations for each componentSpecifying locations for each component
14.92.4.Define the right (east) and bottom (south) edges of the containerDefine the right (east) and bottom (south) edges of the container
14.92.5.Using SpringLayout to lay out a gridUsing SpringLayout to lay out a grid
14.92.6.Using SpringLayout to create a compact gridUsing SpringLayout to create a compact grid
14.92.7.using SpringLayout to create a forms-type layoutusing SpringLayout to create a forms-type layout
14.92.8.Using SpringLayout to create a single rowUsing SpringLayout to create a single row
14.92.9.Using a SpringLayout ManagerUsing a SpringLayout Manager
14.92.10.Springs and Component SizeSprings and Component Size
14.92.11.SpringLayout Utilities