CompoundBorder.java

/* CompoundBorder.java -- 
   Copyright (C) 2003 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath 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 2, or (at your option)
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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package javax.swing.border;

import java.awt.Component;
import java.awt.Graphics;
import java.awt.Insets;

/**
 * A Border that is composed of an interior and an exterior border,
 * where the interior border is tightly nested into the exterior.
 *
 * @author Sascha Brawer (brawer@dandelis.ch)
 */
public class CompoundBorder
  extends AbstractBorder
{
  /**
   * Determined using the <code>serialver</code> tool
   * of Apple/Sun JDK 1.3.1 on MacOS X 10.1.5.
   */
  static final long serialVersionUID = 9054540377030555103L;


  /**
   * The inside border, which is painted between the bordered
   * Component and the outside border. It is valid for
   * <code>insideBorder</code> to be <code>null</code>.
   */
  protected Border insideBorder;


  /**
   * The outside border, which is painted outside both the
   * bordered Component and the inside border. It is valid for
   * <code>outsideBorder</code> to be <code>null</code>.
   */
  protected Border outsideBorder;


  /**
   * Constructs a CompoundBorder whose inside and outside borders
   * are both <code>null</code>. While this does not really make
   * any sense (there exists a class EmptyBorder as well, and not
   * every Component needs to have a border at all), the API
   * specification requires the existence of this constructor.
   *
   * @see EmptyBorder
   */
  public CompoundBorder ()
  {
    this (null, null);
  }


  /**
   * Constructs a CompoundBorder with the specified inside and
   * outside borders.
   *
   * @param outsideBorder the outside border, which is painted to the
   *        outside of both <code>insideBorder</code> and the enclosed
   *        component. It is acceptable to pass <code>null</code>, in
   *        which case no outside border is painted.
   *
   * @param insideBorder the inside border, which is painted to
   *        between <code>outsideBorder</code> and the enclosed
   *        component. It is acceptable to pass <code>null</code>, in
   *        which case no inside border is painted.
   */
  public CompoundBorder (Border outsideBorder, Border insideBorder)
  {
    this.outsideBorder = outsideBorder;
    this.insideBorder = insideBorder;
  }


  /**
   * Determines whether or not this border is opaque. An opaque
   * border fills every pixel in its area when painting. Partially
   * translucent borders must return <code>false</code>, or ugly
   * artifacts can appear on screen.
   *
   * @return <code>true</code> if both the inside and outside borders
   *         are opaque, or <code>false</code> otherwise.
   */
  public boolean isBorderOpaque ()
  {
    /* While it would be safe to assume true for the opacity of
     * a null border, this behavior would not be according to
     * the API specification. Also, it is pathological to have
     * null borders anyway.
     */
    if ((insideBorder == null) || (outsideBorder == null))
      return false;

    return insideBorder.isBorderOpaque()
      && outsideBorder.isBorderOpaque();
  }
    

  /**
   * Paints the compound border by first painting the outside border,
   * then painting the inside border tightly nested into the outside. 
   *
   * @param c the component whose border is to be painted.
   * @param g the graphics for painting.
   * @param x the horizontal position for painting the border.
   * @param y the vertical position for painting the border.
   * @param width the width of the available area for painting the border.
   * @param height the height of the available area for painting the border.
   */
  public void paintBorder(Component c, Graphics g,
                          int x, int y, int width, int height)
  {
    /* If there is an outside border, paint it and reduce the
     * bounding box by its insets.
     */
    if (outsideBorder != null)
    {
      Insets outsideInsets;

      outsideBorder.paintBorder(c, g, x, y, width, height);
      outsideInsets = outsideBorder.getBorderInsets(c);

      x += outsideInsets.left;
      y += outsideInsets.top;

      /* Reduce width and height by the respective extent of the
       * outside border.
       */
      width -= outsideInsets.left + outsideInsets.right;
      height -= outsideInsets.top + outsideInsets.bottom;
    }

    if (insideBorder != null)
      insideBorder.paintBorder(c, g, x, y, width, height);
  }


  /**
   * Changes the specified insets to the insets of this border,
   * which is the sum of the insets of the inside and the outside
   * border.
   *
   * @param c the component in the center of this border.
   * @param insets an Insets object for holding the added insets.
   *
   * @return the <code>insets</code> object.
   */
  public Insets getBorderInsets(Component c, Insets insets)
  {
    Insets borderInsets;

    if (insets == null)
      insets = new Insets (0,0,0,0);
    else
      insets.left = insets.right = insets.top = insets.bottom = 0;

    /* If there is an outside border, add it to insets. */
    if (outsideBorder != null)
    {
      borderInsets = outsideBorder.getBorderInsets(c);
      insets.left += borderInsets.left;
      insets.right += borderInsets.right;
      insets.top += borderInsets.top;
      insets.bottom += borderInsets.bottom;
    }

    /* If there is an inside border, add it to insets. */
    if (insideBorder != null)
    {
      borderInsets = insideBorder.getBorderInsets(c);
      insets.left += borderInsets.left;
      insets.right += borderInsets.right;
      insets.top += borderInsets.top;
      insets.bottom += borderInsets.bottom;
    }

    return insets;
  }


  /**
   * Determines the insets of this border, which is the sum of the
   * insets of the inside and the outside border.
   *
   * @param c the component in the center of this border.
   */
  public Insets getBorderInsets (Component c)
  {
    /* It is not clear why CompoundBorder does not simply inherit
     * the implementation from AbstractBorder. However, we want
     * to be compatible with the API specification, which overrides
     * the getBorderInsets(Component) method.
     */
    return getBorderInsets (c, null);
  }


  /**
   * Returns the outside border, which is painted outside both the
   * bordered Component and the inside border. It is valid for the
   * result to be <code>null</code>.
   */
  public Border getOutsideBorder ()
  {
    return outsideBorder;
  }


  /**
   * Returns the inside border, which is painted between the bordered
   * Component and the outside border. It is valid for the result to
   * be <code>null</code>.
   */
  public Border getInsideBorder ()
  {
    return insideBorder;
  }
}