org.jorigin.gui.layout.WrapLayout Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of jcommon Show documentation
A java common package that enable to deal with various functionalities
There is a newer version: 1.0.14
package org.jorigin.gui.layout;

import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Insets;

import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;

import org.jorigin.Common;

/**
 *  {@link java.awt.FlowLayout FlowLayout} subclass that fully supports wrapping of components. 
 *  This code was originally published by Rob Camick (http://tips4java.wordpress.com/)
 *  @author Rob Camick
 *  @version 1.0.8
 *  @since 1.0.8
 */
public class WrapLayout extends FlowLayout {

  private static final long serialVersionUID = Common.BUILD;

  /**
  * Constructs a new WrapLayout with a left
  * alignment and a default 5-unit horizontal and vertical gap.
  */
  public WrapLayout(){
    super();
  }

  /**
  * Constructs a new FlowLayout with the specified
  * alignment and a default 5-unit horizontal and vertical gap.
  * The value of the alignment argument must be one of
  * {@link java.awt.FlowLayout#LEFT FlowLayout.LEFT}, {@link java.awt.FlowLayout#RIGHT FlowLayout.RIGHT}, 
  * {@link java.awt.FlowLayout#CENTER FlowLayout.CENTER}, {@link java.awt.FlowLayout#LEADING FlowLayout.LEADING}
  * or {@link java.awt.FlowLayout#TRAILING FlowLayout.TRAILING}
  * @param align the alignment value.
  */
  public WrapLayout(int align){
    super(align);
  }

  /**
  * Creates a new flow layout manager with the indicated alignment
  * and the indicated horizontal and vertical gaps.
  * 
  * The value of the alignment argument must be one of
  * {@link java.awt.FlowLayout#LEFT FlowLayout.LEFT}, {@link java.awt.FlowLayout#RIGHT FlowLayout.RIGHT}, 
  * {@link java.awt.FlowLayout#CENTER FlowLayout.CENTER}, {@link java.awt.FlowLayout#LEADING FlowLayout.LEADING}
  * or {@link java.awt.FlowLayout#TRAILING FlowLayout.TRAILING}
  * @param align the alignment value.
  * @param hgap the horizontal gap between components.
  * @param vgap the vertical gap between components.
  */
  public WrapLayout(int align, int hgap, int vgap){
    super(align, hgap, vgap);
  }

  /**
  * Returns the preferred dimensions for this layout given the
  * visible components in the specified target container.
  * @param target the component which needs to be laid out
  * @return the preferred dimensions to lay out the
  * subcomponents of the specified container
  */
  @Override
  public Dimension preferredLayoutSize(Container target){
    return layoutSize(target, true);
  }

  /**
  * Returns the minimum dimensions needed to layout the visible
  * components contained in the specified target container.
  * @param target the component which needs to be laid out
  * @return the minimum dimensions to lay out the
  * subcomponents of the specified container
  */
  @Override
  public Dimension minimumLayoutSize(Container target){
    Dimension minimum = layoutSize(target, false);
    minimum.width -= (getHgap() + 1);
    return minimum;
  }

  /**
  * Returns the minimum or preferred dimension needed to layout the target
  * container.
  *
  * @param target target to get layout size for
  * @param preferred should preferred size be calculated
  * @return the dimension to layout the target container
  */
  private Dimension layoutSize(Container target, boolean preferred){
    synchronized (target.getTreeLock()){
      //  Each row must fit with the width allocated to the containter.
      //  When the container width = 0, the preferred width of the container
      //  has not yet been calculated so lets ask for the maximum.

      int targetWidth = target.getSize().width;

      if (targetWidth == 0){
        targetWidth = Integer.MAX_VALUE;
      }

      int hgap = getHgap();
      int vgap = getVgap();
      Insets insets = target.getInsets();
      int horizontalInsetsAndGap = insets.left + insets.right + (hgap * 2);
      int maxWidth = targetWidth - horizontalInsetsAndGap;

      //  Fit components into the allowed width

      Dimension dim = new Dimension(0, 0);
      int rowWidth = 0;
      int rowHeight = 0;

      int nmembers = target.getComponentCount();

      for (int i = 0; i < nmembers; i++){
        Component m = target.getComponent(i);

        if (m.isVisible()){
          Dimension d = preferred ? m.getPreferredSize() : m.getMinimumSize();

          //  Can't add the component to current row. Start a new row.
          if (rowWidth + d.width > maxWidth){
            addRow(dim, rowWidth, rowHeight);
            rowWidth = 0;
            rowHeight = 0;
          }

          //  Add a horizontal gap for all components after the first

          if (rowWidth != 0){
            rowWidth += hgap;
          }

          rowWidth += d.width;
          rowHeight = Math.max(rowHeight, d.height);
        }
      }

      addRow(dim, rowWidth, rowHeight);

      dim.width += horizontalInsetsAndGap;
      dim.height += insets.top + insets.bottom + vgap * 2;

      //  When using a scroll pane or the DecoratedLookAndFeel we need to
      //  make sure the preferred size is less than the size of the
      //  target containter so shrinking the container size works
      //  correctly. Removing the horizontal gap is an easy way to do this.

      Container scrollPane = SwingUtilities.getAncestorOfClass(JScrollPane.class, target);

      if (scrollPane != null && target.isValid()){
        dim.width -= (hgap + 1);
      }

      return dim;
    }
  }

  /*
   *  A new row has been completed. Use the dimensions of this row
   *  to update the preferred size for the container.
   *
   *  @param dim update the width and height when appropriate
   *  @param rowWidth the width of the row to add
   *  @param rowHeight the height of the row to add
   */
  private void addRow(Dimension dim, int rowWidth, int rowHeight){
    dim.width = Math.max(dim.width, rowWidth);

    if (dim.height > 0)
    {
      dim.height += getVgap();
    }

    dim.height += rowHeight;
  }
}