basicscrollbarui.java

gcc的组建

    Dimension incrDims = incrButton.getPreferredSize();
    Dimension decrDims = decrButton.getPreferredSize();
    
    // calculate and update the track bounds
    SwingUtilities.calculateInnerArea(scrollbar, trackRect);
    trackRect.width -= incrDims.getWidth();
    trackRect.width -= decrDims.getWidth();
    trackRect.x += decrDims.getWidth();

    updateThumbRect();
    
    decrButton.setBounds(vr.x, vr.y, decrDims.width, trackRect.height);
    incrButton.setBounds(trackRect.x + trackRect.width, vr.y, incrDims.width,
                         trackRect.height);
  }

  /**
   * This method lays out the scrollbar vertically.
   *
   * @param sb The JScrollBar to layout.
   */
  protected void layoutVScrollbar(JScrollBar sb)
  {
    Rectangle vr = new Rectangle();
    SwingUtilities.calculateInnerArea(scrollbar, vr);

    Dimension incrDims = incrButton.getPreferredSize();
    Dimension decrDims = decrButton.getPreferredSize();
    
    // Update rectangles
    SwingUtilities.calculateInnerArea(scrollbar, trackRect);
    trackRect.height -= incrDims.getHeight();
    trackRect.height -= decrDims.getHeight();
    trackRect.y += decrDims.getHeight();
    
    updateThumbRect();

    decrButton.setBounds(vr.x, vr.y, trackRect.width, decrDims.height);
    incrButton.setBounds(vr.x, trackRect.y + trackRect.height,
                         trackRect.width, incrDims.height);
  }

  /**
   * Updates the thumb rect.
   */
  void updateThumbRect()
  {
    int max = scrollbar.getMaximum();
    int min = scrollbar.getMinimum();
    int value = scrollbar.getValue();
    int extent = scrollbar.getVisibleAmount();
    if (max - extent <= min)
      {
        if (scrollbar.getOrientation() == JScrollBar.HORIZONTAL)
          {
            thumbRect.x = trackRect.x;
            thumbRect.y = trackRect.y;
            thumbRect.width = getMinimumThumbSize().width;
            thumbRect.height = trackRect.height;
          }
        else
          {
            thumbRect.x = trackRect.x;
            thumbRect.y = trackRect.y;
            thumbRect.width = trackRect.width;
            thumbRect.height = getMinimumThumbSize().height;
          }
      }
    else
      {
        if (scrollbar.getOrientation() == JScrollBar.HORIZONTAL)
          {
            thumbRect.x = trackRect.x;
            thumbRect.width = Math.max(extent * trackRect.width / (max - min),
                getMinimumThumbSize().width);
            int availableWidth = trackRect.width - thumbRect.width;
            thumbRect.x += (value - min) * availableWidth / (max - min - extent);
            thumbRect.y = trackRect.y;
            thumbRect.height = trackRect.height;
          }
        else
          {
            thumbRect.x = trackRect.x;
            thumbRect.height = Math.max(extent * trackRect.height / (max - min),
                    getMinimumThumbSize().height);
            int availableHeight = trackRect.height - thumbRect.height;
            thumbRect.y = trackRect.y 
              + (value - min) * availableHeight / (max - min - extent);
            thumbRect.width = trackRect.width;
          }
      }

  }
  
  /**
   * This method returns the minimum size required for the layout.
   *
   * @param scrollbarContainer The Container that is laid out.
   *
   * @return The minimum size.
   */
  public Dimension minimumLayoutSize(Container scrollbarContainer)
  {
    return preferredLayoutSize(scrollbarContainer);
  }

  /**
   * This method is called when the component is painted.
   *
   * @param g The Graphics object to paint with.
   * @param c The JComponent to paint.
   */
  public void paint(Graphics g, JComponent c)
  {
    paintTrack(g, c, getTrackBounds());
    paintThumb(g, c, getThumbBounds());

    if (trackHighlight == INCREASE_HIGHLIGHT)
      paintIncreaseHighlight(g);
    else if (trackHighlight == DECREASE_HIGHLIGHT)
      paintDecreaseHighlight(g);
  }

  /**
   * This method is called when repainting and the mouse is  pressed in the
   * track. It paints the track below the thumb with the trackHighlight
   * color.
   *
   * @param g The Graphics object to paint with.
   */
  protected void paintDecreaseHighlight(Graphics g)
  {
    Color saved = g.getColor();

    g.setColor(trackHighlightColor);
    if (scrollbar.getOrientation() == HORIZONTAL)
      g.fillRect(trackRect.x, trackRect.y, thumbRect.x - trackRect.x,
                 trackRect.height);
    else
      g.fillRect(trackRect.x, trackRect.y, trackRect.width,
                 thumbRect.y - trackRect.y);
    g.setColor(saved);
  }

  /**
   * This method is called when repainting and the mouse is  pressed in the
   * track. It paints the track above the thumb with the trackHighlight
   * color.
   *
   * @param g The Graphics objet to paint with.
   */
  protected void paintIncreaseHighlight(Graphics g)
  {
    Color saved = g.getColor();

    g.setColor(trackHighlightColor);
    if (scrollbar.getOrientation() == HORIZONTAL)
      g.fillRect(thumbRect.x + thumbRect.width, trackRect.y,
                 trackRect.x + trackRect.width - thumbRect.x - thumbRect.width,
                 trackRect.height);
    else
      g.fillRect(trackRect.x, thumbRect.y + thumbRect.height, trackRect.width,
                 trackRect.y + trackRect.height - thumbRect.y
                 - thumbRect.height);
    g.setColor(saved);
  }

  /**
   * This method paints the thumb.
   *
   * @param g The Graphics object to paint with.
   * @param c The Component that is being painted.
   * @param thumbBounds The thumb bounds.
   */
  protected void paintThumb(Graphics g, JComponent c, Rectangle thumbBounds)
  {
    g.setColor(thumbColor);
    g.fillRect(thumbBounds.x, thumbBounds.y, thumbBounds.width,
               thumbBounds.height);

    BasicGraphicsUtils.drawBezel(g, thumbBounds.x, thumbBounds.y,
                                 thumbBounds.width, thumbBounds.height,
                                 false, false, thumbDarkShadowColor,
                                 thumbDarkShadowColor, thumbHighlightColor,
                                 thumbHighlightColor);
  }

  /**
   * This method paints the track.
   *
   * @param g The Graphics object to paint with.
   * @param c The JComponent being painted.
   * @param trackBounds The track's bounds.
   */
  protected void paintTrack(Graphics g, JComponent c, Rectangle trackBounds)
  {
    Color saved = g.getColor();
    g.setColor(trackColor);
    g.fill3DRect(trackBounds.x, trackBounds.y, trackBounds.width,
                 trackBounds.height, false);
    g.setColor(saved);
  }

  /**
   * This method returns the preferred size for the layout.
   *
   * @param scrollbarContainer The Container to find a size for.
   *
   * @return The preferred size for the layout.
   */
  public Dimension preferredLayoutSize(Container scrollbarContainer)
  {
    if (scrollbarContainer instanceof JComponent)
      return getPreferredSize((JComponent) scrollbarContainer);
    else
      return null;
  }

  /**
   * This method removes a child component from the layout.
   *
   * @param child The child to remove.
   */
  public void removeLayoutComponent(Component child)
  {
    // You should not be removing stuff from this component.
  }

  /**
   * The method scrolls the thumb by a block in the  direction specified.
   *
   * @param direction The direction to scroll.
   */
  protected void scrollByBlock(int direction)
  {
    scrollbar.setValue(scrollbar.getValue()
                       + scrollbar.getBlockIncrement(direction));
  }

  /**
   * The method scrolls the thumb by a unit in the direction specified.
   *
   * @param direction The direction to scroll.
   */
  protected void scrollByUnit(int direction)
  {
    scrollbar.setValue(scrollbar.getValue()
                       + scrollbar.getUnitIncrement(direction));
  }

  /**
   * This method sets the thumb's bounds.
   *
   * @param x The X position of the thumb.
   * @param y The Y position of the thumb.
   * @param width The width of the thumb.
   * @param height The height of the thumb.
   */
  protected void setThumbBounds(int x, int y, int width, int height)
  {
    thumbRect.x = x;
    thumbRect.y = y;
    thumbRect.width = width;
    thumbRect.height = height;
  }

  /**
   * This method uninstalls any components that  are a part of or related to
   * this scrollbar.
   */
  protected void uninstallComponents()
  {
    if (incrButton != null)
      scrollbar.remove(incrButton);
    if (decrButton != null)
      scrollbar.remove(decrButton);
  }

  /**
   * This method uninstalls any defaults that this scrollbar acquired from the
   * Basic Look and Feel defaults.
   */
  protected void uninstallDefaults()
  {
    scrollbar.setForeground(null);
    scrollbar.setBackground(null);
    LookAndFeel.uninstallBorder(scrollbar);
    incrButton = null;
    decrButton = null;
  }

  /**
   * This method uninstalls any keyboard actions this scrollbar acquired
   * during install.
   */
  protected void uninstallKeyboardActions()
  {
    // FIXME: implement.
  }

  /**
   * This method uninstalls any listeners that were registered during install.
   */
  protected void uninstallListeners()
  {
    if (scrollTimer != null)
      scrollTimer.removeActionListener(scrollListener);

    if (scrollbar != null)
      {
        scrollbar.getModel().removeChangeListener(modelListener);
        scrollbar.removePropertyChangeListener(propertyChangeListener);
        scrollbar.removeMouseListener(trackListener);
        scrollbar.removeMouseMotionListener(trackListener);
      }

    if (decrButton != null)
      decrButton.removeMouseListener(buttonListener);
    if (incrButton != null)
      incrButton.removeMouseListener(buttonListener);
    
    propertyChangeListener = null;
    modelListener = null;
    buttonListener = null;
    trackListener = null;
    scrollListener = null;
  }

  /**
   * This method uninstalls the UI. This includes removing any defaults,
   * listeners, and components that this UI may have initialized. It also
   * nulls any instance data.
   *
   * @param c The Component to uninstall for.
   */
  public void uninstallUI(JComponent c)
  {
    uninstallListeners();
    uninstallDefaults();
    uninstallComponents();

    scrollTimer = null;

    thumbRect = null;
    trackRect = null;

    trackColor = null;
    trackHighlightColor = null;
    thumbColor = null;
    thumbHighlightColor = null;
    thumbDarkShadowColor = null;
    thumbLightShadowColor = null;

    scrollbar = null;
  }

  /**
   * This method returns the value in the scrollbar's range given the y
   * coordinate. If the value is out of range, it will return the closest
   * legal value.
   * This is package-private to avoid an accessor method.
   *
   * @param yPos The y coordinate to calculate a value for.
   *
   * @return The value for the y coordinate.
   */
  int valueForYPosition(int yPos)
  {
    int min = scrollbar.getMinimum();
    int max = scrollbar.getMaximum();
    int len = trackRect.height;

    int value;

    // If the length is 0, you shouldn't be able to even see where the thumb is.
    // This really shouldn't ever happen, but just in case, we'll return the middle.
    if (len == 0)
      return ((max - min) / 2);

    value = ((yPos - trackRect.y) * (max - min) / len + min);

    // If this isn't a legal value, then we'll have to move to one now.
    if (value > max)
      value = max;
    else if (value < min)
      value = min;
    return value;
  }

  /**
   * This method returns the value in the scrollbar's range given the x
   * coordinate. If the value is out of range, it will return the closest
   * legal value.
   * This is package-private to avoid an accessor method.
   *
   * @param xPos The x coordinate to calculate a value for.
   *
   * @return The value for the x coordinate.
   */
  int valueForXPosition(int xPos)
  {
    int min = scrollbar.getMinimum();
    int max = scrollbar.getMaximum();
    int len = trackRect.width;

    int value;

    // If the length is 0, you shouldn't be able to even see where the slider is.
    // This really shouldn't ever happen, but just in case, we'll return the middle.
    if (len == 0)
      return ((max - min) / 2);

    value = ((xPos - trackRect.x) * (max - min) / len + min);

    // If this isn't a legal value, then we'll have to move to one now.
    if (value > max)
      value = max;
    else if (value < min)
      value = min;
    return value;
  }
}