path: root/libjava/classpath/javax/swing/plaf/basic/BasicArrowButton.java

/* BasicArrowButton.java --
   Copyright (C) 2004, 2005, 2006 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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General Public License for more details.

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02110-1301 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
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package javax.swing.plaf.basic;

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Polygon;

import javax.swing.ButtonModel;
import javax.swing.JButton;
import javax.swing.SwingConstants;

/**
 * A button that displays an arrow (triangle) that points {@link #NORTH},
 * {@link #SOUTH}, {@link #EAST} or {@link #WEST}.  This button is used by
 * the {@link BasicComboBoxUI} class.
 *
 * @see BasicComboBoxUI#createArrowButton
 */
public class BasicArrowButton extends JButton implements SwingConstants
{

  /**
   * The direction that the arrow points.
   *
   * @see #getDirection()
   */
  protected int direction;

  /**
   * The color the arrow is painted in if disabled and the bottom and right
   * edges of the button.
   * This is package-private to avoid an accessor method.
   */
  transient Color shadow = Color.GRAY;

  /**
   * The color the arrow is painted in if enabled and the bottom and right
   * edges of the button.
   * This is package-private to avoid an accessor method.
   */
  transient Color darkShadow = new Color(102, 102, 102);

  /**
   * The top and left edges of the button.
   * This is package-private to avoid an accessor method.
   */
  transient Color highlight = Color.WHITE;

  /**
   * Creates a new <code>BasicArrowButton</code> object with an arrow pointing
   * in the specified direction.  If the <code>direction</code> is not one of
   * the specified constants, no arrow is drawn.
   *
   * @param direction The direction the arrow points in (one of:
   * {@link #NORTH}, {@link #SOUTH}, {@link #EAST} and {@link #WEST}).
   */
  public BasicArrowButton(int direction)
  {
    super();
    setDirection(direction);
    setFocusable(false);
  }

  /**
   * Creates a new BasicArrowButton object with the given colors and
   * direction.
   *
   * @param direction The direction to point in (one of:
   * {@link #NORTH}, {@link #SOUTH}, {@link #EAST} and {@link #WEST}).
   * @param background The background color.
   * @param shadow The shadow color.
   * @param darkShadow The dark shadow color.
   * @param highlight The highlight color.
   */
  public BasicArrowButton(int direction, Color background, Color shadow,
                          Color darkShadow, Color highlight)
  {
    this(direction);
    setBackground(background);
    this.shadow = shadow;
    this.darkShadow = darkShadow;
    this.highlight = highlight;
    setFocusable(false);
  }

  /**
   * Returns whether the focus can traverse to this component.  This method
   * always returns <code>false</code>.
   *
   * @return <code>false</code>.
   */
  public boolean isFocusTraversable()
  {
    return false;
  }

  /**
   * Returns the direction of the arrow (one of: {@link #NORTH},
   * {@link #SOUTH}, {@link #EAST} and {@link #WEST}).
   *
   * @return The direction of the arrow.
   */
  public int getDirection()
  {
    return direction;
  }

  /**
   * Sets the direction of the arrow.
   *
   * @param dir The new direction of the arrow (one of: {@link #NORTH},
   *            {@link #SOUTH}, {@link #EAST} and {@link #WEST}).
   */
  public void setDirection(int dir)
  {
    this.direction = dir;
  }

  /**
   * Paints the arrow button. The painting is delegated to the
   * paintTriangle method.
   *
   * @param g The Graphics object to paint with.
   */
  public void paint(Graphics g)
  {
    super.paint(g);

    int height = getHeight();
    int size = height / 4;

    int x = (getWidth() - size) / 2;
    int y = (height - size) / 2;

    ButtonModel m = getModel();
    if (m.isArmed())
      {
        x++;
        y++;
      }

    paintTriangle(g, x, y, size, direction, isEnabled());
  }

  /**
   * Returns the preferred size of the arrow button.
   *
   * @return The preferred size (always 16 x 16).
   */
  public Dimension getPreferredSize()
  {
    // since Dimension is NOT immutable, we must return a new instance
    // every time (if we return a cached value, the caller might modify it)
    // - tests show that the reference implementation does the same.
    return new Dimension(16, 16);
  }

  /**
   * Returns the minimum size of the arrow button.
   *
   * @return The minimum size (always 5 x 5).
   */
  public Dimension getMinimumSize()
  {
    // since Dimension is NOT immutable, we must return a new instance
    // every time (if we return a cached value, the caller might modify it)
    // - tests show that the reference implementation does the same.
    return new Dimension(5, 5);
  }

  /**
   * Returns the maximum size of the arrow button.
   *
   * @return The maximum size (always Integer.MAX_VALUE x Integer.MAX_VALUE).
   */
  public Dimension getMaximumSize()
  {
    // since Dimension is NOT immutable, we must return a new instance
    // every time (if we return a cached value, the caller might modify it)
    // - tests show that the reference implementation does the same.
    return new Dimension(Integer.MAX_VALUE, Integer.MAX_VALUE);
  }

  /**
   * Paints a triangle with the given size, location and direction.  It is
   * difficult to explain the rationale behind the positioning of the triangle
   * relative to the given (x, y) position - by trial and error we seem to
   * match the behaviour of the reference implementation (which is missing a
   * specification for this method).
   *
   * @param g  the graphics device.
   * @param x  the x-coordinate for the triangle's location.
   * @param y  the y-coordinate for the triangle's location.
   * @param size  the arrow size (depth).
   * @param direction  the direction of the arrow (one of: {@link #NORTH},
   *            {@link #SOUTH}, {@link #EAST} and {@link #WEST}).
   * @param isEnabled  if <code>true</code> the arrow is drawn in the enabled
   *                   state, otherwise it is drawn in the disabled state.
   */
  public void paintTriangle(Graphics g, int x, int y, int size, int direction,
                            boolean isEnabled)
  {
    Color savedColor = g.getColor();
    switch (direction)
      {
      case NORTH:
        paintTriangleNorth(g, x, y, size, isEnabled);
        break;
      case SOUTH:
        paintTriangleSouth(g, x, y, size, isEnabled);
        break;
      case LEFT:
      case WEST:
        paintTriangleWest(g, x, y, size, isEnabled);
        break;
      case RIGHT:
      case EAST:
        paintTriangleEast(g, x, y, size, isEnabled);
        break;
      }
    g.setColor(savedColor);
  }

  /**
   * Paints an upward-pointing triangle.  This method is called by the
   * {@link #paintTriangle(Graphics, int, int, int, int, boolean)} method.
   *
   * @param g  the graphics device.
   * @param x  the x-coordinate for the anchor point.
   * @param y  the y-coordinate for the anchor point.
   * @param size  the arrow size (depth).
   * @param isEnabled  if <code>true</code> the arrow is drawn in the enabled
   *                   state, otherwise it is drawn in the disabled state.
   */
  private void paintTriangleNorth(Graphics g, int x, int y, int size,
          boolean isEnabled)
  {
    int tipX = x + (size - 2) / 2;
    int tipY = y;
    int baseX1 = tipX - (size - 1);
    int baseX2 = tipX + (size - 1);
    int baseY = y + (size - 1);
    Polygon triangle = new Polygon();
    triangle.addPoint(tipX, tipY);
    triangle.addPoint(baseX1, baseY);
    triangle.addPoint(baseX2, baseY);
    if (isEnabled)
     {
       g.setColor(Color.DARK_GRAY);
       g.fillPolygon(triangle);
       g.drawPolygon(triangle);
     }
    else
     {
       g.setColor(Color.GRAY);
       g.fillPolygon(triangle);
       g.drawPolygon(triangle);
       g.setColor(Color.WHITE);
       g.drawLine(baseX1 + 1, baseY + 1, baseX2 + 1, baseY + 1);
     }
  }

  /**
   * Paints an downward-pointing triangle.  This method is called by the
   * {@link #paintTriangle(Graphics, int, int, int, int, boolean)} method.
   *
   * @param g  the graphics device.
   * @param x  the x-coordinate for the anchor point.
   * @param y  the y-coordinate for the anchor point.
   * @param size  the arrow size (depth).
   * @param isEnabled  if <code>true</code> the arrow is drawn in the enabled
   *                   state, otherwise it is drawn in the disabled state.
   */
  private void paintTriangleSouth(Graphics g, int x, int y, int size,
          boolean isEnabled)
  {
    int tipX = x + (size - 2) / 2;
    int tipY = y + (size - 1);
    int baseX1 = tipX - (size - 1);
    int baseX2 = tipX + (size - 1);
    int baseY = y;
    Polygon triangle = new Polygon();
    triangle.addPoint(tipX, tipY);
    triangle.addPoint(baseX1, baseY);
    triangle.addPoint(baseX2, baseY);
    if (isEnabled)
     {
       g.setColor(Color.DARK_GRAY);
       g.fillPolygon(triangle);
       g.drawPolygon(triangle);
     }
    else
     {
       g.setColor(Color.GRAY);
       g.fillPolygon(triangle);
       g.drawPolygon(triangle);
       g.setColor(Color.WHITE);
       g.drawLine(tipX + 1, tipY, baseX2, baseY + 1);
       g.drawLine(tipX + 1, tipY + 1, baseX2 + 1, baseY + 1);
     }
  }

  /**
   * Paints a right-pointing triangle.  This method is called by the
   * {@link #paintTriangle(Graphics, int, int, int, int, boolean)} method.
   *
   * @param g  the graphics device.
   * @param x  the x-coordinate for the anchor point.
   * @param y  the y-coordinate for the anchor point.
   * @param size  the arrow size (depth).
   * @param isEnabled  if <code>true</code> the arrow is drawn in the enabled
   *                   state, otherwise it is drawn in the disabled state.
   */
  private void paintTriangleEast(Graphics g, int x, int y, int size,
          boolean isEnabled)
  {
    int tipX = x + (size - 1);
    int tipY = y + (size - 2) / 2;
    int baseX = x;
    int baseY1 = tipY - (size - 1);
    int baseY2 = tipY + (size - 1);

    Polygon triangle = new Polygon();
    triangle.addPoint(tipX, tipY);
    triangle.addPoint(baseX, baseY1);
    triangle.addPoint(baseX, baseY2);
    if (isEnabled)
     {
       g.setColor(Color.DARK_GRAY);
       g.fillPolygon(triangle);
       g.drawPolygon(triangle);
     }
    else
     {
       g.setColor(Color.GRAY);
       g.fillPolygon(triangle);
       g.drawPolygon(triangle);
       g.setColor(Color.WHITE);
       g.drawLine(baseX + 1, baseY2, tipX, tipY + 1);
       g.drawLine(baseX + 1, baseY2 + 1, tipX + 1, tipY + 1);
     }
  }

  /**
   * Paints a left-pointing triangle.  This method is called by the
   * {@link #paintTriangle(Graphics, int, int, int, int, boolean)} method.
   *
   * @param g  the graphics device.
   * @param x  the x-coordinate for the anchor point.
   * @param y  the y-coordinate for the anchor point.
   * @param size  the arrow size (depth).
   * @param isEnabled  if <code>true</code> the arrow is drawn in the enabled
   *                   state, otherwise it is drawn in the disabled state.
   */
  private void paintTriangleWest(Graphics g, int x, int y, int size,
          boolean isEnabled)
  {
    int tipX = x;
    int tipY = y + (size - 2) / 2;
    int baseX = x + (size - 1);
    int baseY1 = tipY - (size - 1);
    int baseY2 = tipY + (size - 1);

    Polygon triangle = new Polygon();
    triangle.addPoint(tipX, tipY);
    triangle.addPoint(baseX, baseY1);
    triangle.addPoint(baseX, baseY2);
    if (isEnabled)
     {
       g.setColor(Color.DARK_GRAY);
       g.fillPolygon(triangle);
       g.drawPolygon(triangle);
     }
    else
     {
       g.setColor(Color.GRAY);
       g.fillPolygon(triangle);
       g.drawPolygon(triangle);
       g.setColor(Color.WHITE);
       g.drawLine(baseX + 1, baseY1 + 1, baseX + 1, baseY2 + 1);
     }
  }

}