示例#1
0
  /**
   * Draws a double headed arrow with arrow heads of a given width and height.
   *
   * @param aG the canvas to draw on;
   * @param aX1 the starting X position of the arrow;
   * @param aY1 the starting Y position of the arrow;
   * @param aX2 the ending X position of the arrow;
   * @param aY2 the ending Y position of the arrow;
   * @param aArrowWidth the total width of the arrow head;
   * @param aArrowHeight the total height of the arrow head.
   */
  public static final void drawDoubleHeadedArrow(
      final Graphics aG,
      final int aX1,
      final int aY1,
      final int aX2,
      final int aY2,
      final int aArrowWidth,
      final int aArrowHeight) {
    final Graphics2D g2d = (Graphics2D) aG.create();

    final int lineWidth = Math.abs(aX2 - aX1);
    final int threshold = (2 * aArrowWidth) + 2;
    try {
      int x1 = aX1;
      int x2 = aX2;

      if (lineWidth > threshold) {
        drawArrowHead(g2d, aX1, aY1, LEFT_FACING, aArrowWidth, aArrowHeight);
        // why x2 needs to be shifted by one pixel is beyond me...
        drawArrowHead(g2d, aX2 + 1, aY2, RIGHT_FACING, aArrowWidth, aArrowHeight);

        x1 += aArrowWidth - 1;
        x2 -= aArrowWidth + 1;
      }

      g2d.drawLine(x1, aY1, x2, aY2);
    } finally {
      g2d.dispose();
    }
  }
示例#2
0
  /**
   * Draws a single arrow head
   *
   * @param aG the canvas to draw on;
   * @param aXpos the X position of the arrow head;
   * @param aYpos the (center) Y position of the arrow head;
   * @param aFactor +1 to have a left-facing arrow head, -1 to have a right-facing arrow head;
   * @param aArrowWidth the total width of the arrow head;
   * @param aArrowHeight the total height of the arrow head.
   */
  public static final void drawArrowHead(
      final Graphics2D aG,
      final int aXpos,
      final int aYpos,
      final int aFactor,
      final int aArrowWidth,
      final int aArrowHeight) {
    final double halfHeight = aArrowHeight / 2.0;
    final int x1 = aXpos + (aFactor * aArrowWidth);
    final int y1 = (int) Math.ceil(aYpos - halfHeight);
    final int y2 = (int) Math.floor(aYpos + halfHeight);

    final Polygon arrowHead = new Polygon();
    arrowHead.addPoint(aXpos, aYpos);
    arrowHead.addPoint(x1, y1);
    arrowHead.addPoint(x1, y2);

    aG.fill(arrowHead);
  }