gcc/libjava/javax/swing/border/MatteBorder.java

/* MatteBorder.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
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02111-1307 USA.

Linking this library statically or dynamically with other modules is
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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.Color;
import java.awt.Component;
import java.awt.Graphics;
import java.awt.Insets;
import javax.swing.Icon;


/**
 * A border that is filled with either a solid color or with repeated
 * icon tiles.
 *
 * <p><img src="doc-files/MatteBorder-1.png" width="500" height="150"
 * alt="[Two MatteBorders]" />
 *
 * @author Sascha Brawer (brawer@dandelis.ch)
 */
public class MatteBorder
  extends EmptyBorder
{
  /**
   * Determined using the <code>serialver</code> tool
   * of Apple/Sun JDK 1.3.1 on MacOS X 10.1.5.
   */
  static final long serialVersionUID = 4422248989617298224L;
  
  
  /**
   * The color that is used for filling the border, or
   * <code>null</code> if the border is filled with repetitions of a
   * tile icon.
   *
   * @see #tileIcon
   */
  protected Color color;
  
  
  /**
   * The icon is used for filling the border with a tile, or
   * <code>null</code> if the border is filled with a solid
   * color.
   *
   * @see #color
   */
  protected Icon tileIcon;
  
  
  /**
   * Constructs a MatteBorder given the width on each side
   * and a fill color.
   *
   * <p><img src="doc-files/MatteBorder-2.png" width="500" height="150"
   * alt="[A picture of a MatteBorder made by this constructor]" />
   *
   * @param top the width of the border at its top edge.
   * @param left the width of the border at its left edge.
   * @param bottom the width of the border at its bottom edge.
   * @param right the width of the border at its right edge.
   * @param matteColor the color for filling the border.
   */
  public MatteBorder(int top, int left, int bottom, int right,
                     Color matteColor)
  {
    super(top, left, bottom, right);

    if (matteColor == null)
      throw new IllegalArgumentException();

    this.color = matteColor;
  }


  /**
   * Constructs a MatteBorder given its insets and fill color.
   *
   * <p><img src="doc-files/MatteBorder-3.png" width="500" height="150"
   * alt="[A picture of a MatteBorder made by this constructor]" />
   *
   * @param borderInsets an Insets object whose <code>top</code>,
   *        <code>left</code>, <code>bottom</code> and <code>right</code>
   *        fields indicate the with of the border at the respective
   *        edge.
   *
   * @param matteColor the color for filling the border.
   */
  public MatteBorder(Insets borderInsets, Color matteColor)
  {
    this(borderInsets.top, borderInsets.left,
         borderInsets.bottom, borderInsets.right,
         matteColor);
  }


  /**
   * Constructs a MatteBorder given the width on each side
   * and an icon for tiling the border area.
   *
   * <p><img src="doc-files/MatteBorder-4.png" width="500" height="150"
   * alt="[A picture of a MatteBorder made by this constructor]" />
   *
   * @param top the width of the border at its top edge.
   * @param left the width of the border at its left edge.
   * @param bottom the width of the border at its bottom edge.
   * @param right the width of the border at its right edge.
   * @param tileIcon an icon for tiling the border area.
   */
  public MatteBorder(int top, int left, int bottom, int right,
                     Icon tileIcon)
  {
    super(top, left, bottom, right);

    if (tileIcon == null)
      throw new IllegalArgumentException();

    this.tileIcon = tileIcon;
  }


  /**
   * Constructs a MatteBorder given its insets and an icon
   * for tiling the border area.
   *
   * <p><img src="doc-files/MatteBorder-5.png" width="500" height="150"
   * alt="[A picture of a MatteBorder made by this constructor]" />
   *
   * @param borderInsets an Insets object whose <code>top</code>,
   *        <code>left</code>, <code>bottom</code> and <code>right</code>
   *        fields indicate the with of the border at the respective
   *        edge.
   *
   * @param tileIcon an icon for tiling the border area.
   */
  public MatteBorder(Insets borderInsets, Icon tileIcon)
  {
    this(borderInsets.top, borderInsets.left,
         borderInsets.bottom, borderInsets.right,
         tileIcon);
  }
  
  
  /**
   * Constructs a MatteBorder given an icon for tiling the
   * border area. The icon width is used for the border insets
   * at the left and right edge, the icon height for the top and
   * bottom edge.
   *
   * <p><img src="doc-files/MatteBorder-6.png" width="500" height="150"
   * alt="[A picture of a MatteBorder made by this constructor]" />
   *
   * @param tileIcon an icon for tiling the border area.
   */
  public MatteBorder(Icon tileIcon)
  {
    this(-1, -1, -1, -1, tileIcon);
  }
  
  
  /**
   * Paints the border for a given component.
   *
   * @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)
  {
    Insets i = getBorderInsets();
    paintEdge(c, g, x, y, width, i.top, 0, 0);      // top edge
    paintEdge(c, g, x, y + height - i.bottom,       // bottom edge
              width, i.bottom,
              0, height - i.bottom);
    paintEdge(c, g, x, y + i.top,                   // left edge
              i.left, height - i.top,
              0, i.top);
    paintEdge(c, g, x + width - i.right, y + i.top, // right edge
              i.right, height - i.bottom,
              width - i.right, i.top);
  }
  
  
  /**
   * Measures the width of this border.
   *
   * @param c the component whose border is to be measured.
   *
   * @return an Insets object whose <code>left</code>, <code>right</code>,
   *         <code>top</code> and <code>bottom</code> fields indicate the
   *         width of the border at the respective edge.
   *
   * @see #getBorderInsets(java.awt.Component, java.awt.Insets)
   */
  public Insets getBorderInsets(Component c)
  {
    /* There is no obvious reason for overriding this method, but we
     * try to have exactly the same API as the Sun reference
     * implementation.
     */
    return this.getBorderInsets(c, null);
  }
  
  
  /**
   * Measures the width of this border, storing the results into a
   * pre-existing Insets object.
   *
   * @param insets an Insets object for holding the result values.
   *        After invoking this method, the <code>left</code>,
   *        <code>right</code>, <code>top</code> and
   *        <code>bottom</code> fields indicate the width of the
   *        border at the respective edge.
   *
   * @return the same object that was passed for <code>insets</code>.
   *
   * @see #getBorderInsets()
   */
  public Insets getBorderInsets(Component c, Insets insets)
  {
    if (insets == null)
      insets = new Insets(0, 0, 0, 0);

    if ((tileIcon != null)
        && (top < 0) && (left < 0)
        && (right < 0) && (bottom < 0))
    {
      insets.left = insets.right = tileIcon.getIconWidth();
      insets.top = insets.bottom = tileIcon.getIconHeight();
      return insets;
    }

    /* Copy top, left, bottom and right into the respective
     * field of insets.
     */
    return super.getBorderInsets(c, insets);
  }
  
  
  /**
   * Measures the width of this border.
   *
   * @return an Insets object whose <code>left</code>, <code>right</code>,
   *         <code>top</code> and <code>bottom</code> fields indicate the
   *         width of the border at the respective edge.
   *
   * @see #getBorderInsets(java.awt.Component, java.awt.Insets)
   */
  public Insets getBorderInsets()
  {
    /* The inherited implementation of EmptyBorder.isBorderOpaque()
     * would do the same. It is not clear why this is overriden in the
     * Sun implementation, at least not from just reading the JavaDoc.
     */
    return this.getBorderInsets(null, null);
  }
  
  
  /**
   * Returns the color that is used for filling the border, or
   * <code>null</code> if the border is filled with repetitions of a
   * tile icon.
   */
  public Color getMatteColor()
  {
    return color;
  }
  
  
  /**
   * Returns the icon is used for tiling the border, or
   * <code>null</code> if the border is filled with a color instead of
   * an icon.
   */
  public Icon getTileIcon()
  {
    return tileIcon;
  }
  
  
  /**
   * Determines whether this border fills every pixel in its area
   * when painting.
   *
   * @return <code>true</code> if the border is filled with an
   *         opaque color; <code>false</code> if it is filled with
   *         a semi-transparent color or with an icon.
   */
  public boolean isBorderOpaque()
  {
    return (color != null) && (color.getAlpha() == 255);
  }
  

  /**
   * Paints a rectangular area of the border. This private helper
   * method is called once for each of the border edges
   * by {@link #paintBorder}.
   *
   * @param c the component whose border is being painted.
   * @param g the graphics for painting.
   * @param x the horizontal position of the rectangular area.
   * @param y the vertical position of the rectangular area.
   * @param width the width of the rectangular area.
   * @param height the height of the rectangular area.
   * @param dx the x displacement for repeating the tile.
   * @param dy the y displacement for repeating the tile.
   */
  private void paintEdge(Component c, Graphics g,
                         int x, int y, int width, int height,
                         int dx, int dy)
  {
    Color oldColor;
    int iconWidth, iconHeight;
    Graphics clipped;

    if ((width <= 0) || (height <= 0))
      return;

    /* Paint a colored rectangle if desired. */
    if (color != null)
    {
      oldColor = g.getColor();
      try
      {
        g.setColor(color);
        g.fillRect(x, y, width, height);
      }
      finally
      {
        g.setColor(oldColor);
      }
      return;
    }

    /* Determine the width and height of the icon. Some icons return
     * -1 if it is an image whose dimensions have not yet been
     * retrieved. There is not much we can do about this, but we
     * should at least avoid entering the paint loop below
     * with negative increments.
     */
    iconWidth = tileIcon.getIconWidth();
    iconHeight = tileIcon.getIconHeight();
    if ((iconWidth <= 0) || (iconHeight <= 0))
      return;

    dx = dx % iconWidth;
    dy = dy % iconHeight;

    clipped = g.create();
    try
    {
      clipped.setClip(x, y, width, height);
      for (int ty = y - dy; ty < y + height; ty += iconHeight)
        for (int tx = x - dx; tx < x + width; tx += iconWidth)
          tileIcon.paintIcon(c, clipped, tx, ty);
    }
    finally
    {
      clipped.dispose();
    }
  }
}