// --------------------- RowHeightResizer.java --------------------------

/************************************************************************
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
************************************************************************/
// awt
import java.awt.Cursor;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.event.MouseEvent;
// swingx
import javax.swing.JTable;
import javax.swing.event.MouseInputAdapter;

/**
 * <code>RowHeightResizer</code> class provides support for resizing rows
 * in a <code>javax.swing.JTable</code> and extends
 * <code>javax.swing.event.MouseInputAdapter</code>.
 *
 * @author Thomas Kellerer
 * @see    Sun Java Developer's Forum Member[thomas.kellerer]
 * @see    <a href="http://forum.java.sun.com/thread.jspa?threadID=453665&messageID=2144116">See post</a>
 */
public class RowHeightResizer extends MouseInputAdapter
{
  private JTable table;
  private boolean active;
  private boolean rowSelectionAllowed;
  private int row;
  private int startY;
  private int startHeight;

  private static final int PIXELS = 5;
  private Cursor lastCursor;
  private static Cursor resizeCursor = Cursor.getPredefinedCursor(Cursor.S_RESIZE_CURSOR);

  /**
   * Class constructor sets the reference to this table and adds
   * mouse listeners to this component.
   *
   * @param table <code>javax.swing.JTable</code> reference for this instance.
   */
  public RowHeightResizer(JTable table)
  {
    this.table = table;
    this.table.addMouseListener(this);
    this.table.addMouseMotionListener(this);
    this.row = -1;
  }

  /**
   * Checks for <code>null</code> table reference, returns
   * and does nothing if true; otherwise, the mouse listeners are
   * removed.
   */
  public void done()
  {
    if (this.table == null) return;
    this.table.removeMouseListener(this);
    this.table.removeMouseMotionListener(this);
  }

  /**
   * Detects mouse movements.
   *
   * @param e <code>java.awt.event.MouseEvent</code>
   *
   */
  public void mouseMoved(MouseEvent e)
  {
    Point p = e.getPoint();

    if (this.isMouseOverRowMargin(p))
    {
      if (this.lastCursor == null)
      {
        this.lastCursor = this.table.getCursor();
      }
      this.table.setCursor(resizeCursor);
    }
    else
    {
      this.table.setCursor(this.lastCursor);
    }
  }

  /**
   * Detects mouse-pressed events.
   *
   * @param e <code>java.awt.event.MouseEvent</code> reference of this event.
   *
   */
  public void mousePressed(MouseEvent e)
  {
    Point p = e.getPoint();

    if (this.isMouseOverRowMargin(p))
    {
      this.active = true;
      this.startY = p.y;
      this.startHeight = table.getRowHeight(row);
      this.rowSelectionAllowed = this.table.getRowSelectionAllowed();
      this.table.setRowSelectionAllowed(false);
    }
  }

  /**
   * Detects dragged event for this mouse event.
   *
   * @param e <code>java.awt.event.MouseEvent</code> reference of this event.
   */
  public void mouseDragged(MouseEvent e)
  {
    if (!active) return;

    int newHeight = startHeight + e.getY() - startY;
    newHeight = Math.max(1, newHeight);
    this.table.setRowHeight(row, newHeight);
  }

  /**
   * Detects mouse released event.
   *
   * @param e <code>java.awt.event.MouseEvent</code> reference of this event.
   */
  public void mouseReleased(MouseEvent e)
  {
    if (!active) return;

    this.table.setRowSelectionAllowed(this.rowSelectionAllowed);
    this.active = false;
    this.row = -1;
  }

  /**
   * Indicates whether mouse is over the row margin.
   *
   * @param  e <code>java.util.Point</code> location of this row margin.
   * @return   boolean value indicating whether this mouse is over the row margin.
   */
  private boolean isMouseOverRowMargin(Point p)
  {
    if (!table.isEnabled()) return false;
    this.row = table.rowAtPoint(p);
    int column = table.columnAtPoint(p);

    if (row == -1 || column == -1) return false;

    Rectangle r = table.getCellRect(row, column, true);

    if (p.y >= r.y + r.height - PIXELS)
    {
      return true;
    }
    return false;
  }

}