/**
 * Constructs a new rule with default properties. Rules are not typically
 * constructed directly, but by adding to a panel or an existing mark via
 * {@link pv.Mark#add}.
 *
 * @class Represents a horizontal or vertical rule. Rules are frequently used
 * for axes and grid lines. For example, specifying only the bottom property
 * draws horizontal rules, while specifying only the left draws vertical
 * rules. Rules can also be used as thin bars. The visual style is controlled in
 * the same manner as lines.
 *
 * <p>Rules are positioned exclusively the standard box model properties. The
 * following combinations of properties are supported:
 *
 * <table>
 * <thead><th style="width:12em;">Properties</th><th>Orientation</th></thead>
 * <tbody>
 * <tr><td>left</td><td>vertical</td></tr>
 * <tr><td>right</td><td>vertical</td></tr>
 * <tr><td>left, bottom, top</td><td>vertical</td></tr>
 * <tr><td>right, bottom, top</td><td>vertical</td></tr>
 * <tr><td>top</td><td>horizontal</td></tr>
 * <tr><td>bottom</td><td>horizontal</td></tr>
 * <tr><td>top, left, right</td><td>horizontal</td></tr>
 * <tr><td>bottom, left, right</td><td>horizontal</td></tr>
 * <tr><td>left, top, height</td><td>vertical</td></tr>
 * <tr><td>left, bottom, height</td><td>vertical</td></tr>
 * <tr><td>right, top, height</td><td>vertical</td></tr>
 * <tr><td>right, bottom, height</td><td>vertical</td></tr>
 * <tr><td>left, top, width</td><td>horizontal</td></tr>
 * <tr><td>left, bottom, width</td><td>horizontal</td></tr>
 * <tr><td>right, top, width</td><td>horizontal</td></tr>
 * <tr><td>right, bottom, width</td><td>horizontal</td></tr>
 * </tbody>
 * </table>
 *
 * <p>Small rules can be used as tick marks; alternatively, a {@link Dot} with
 * the "tick" shape can be used.
 *
 * <p>See also the <a href="../../api/Rule.html">Rule guide</a>.
 *
 * @see pv.Line
 * @extends pv.Mark
 */
pv.Rule = function() {
  pv.Mark.call(this);
};

pv.Rule.prototype = pv.extend(pv.Mark)
    .property("width", Number)
    .property("height", Number)
    .property("lineWidth", Number)
    .property("strokeStyle", pv.color);

pv.Rule.prototype.type = "rule";

/**
 * The width of the rule, in pixels. If the left position is specified, the rule
 * extends rightward from the left edge; if the right position is specified, the
 * rule extends leftward from the right edge.
 *
 * @type number
 * @name pv.Rule.prototype.width
 */

/**
 * The height of the rule, in pixels. If the bottom position is specified, the
 * rule extends upward from the bottom edge; if the top position is specified,
 * the rule extends downward from the top edge.
 *
 * @type number
 * @name pv.Rule.prototype.height
 */

/**
 * The width of stroked lines, in pixels; used in conjunction with
 * <tt>strokeStyle</tt> to stroke the rule. The default value is 1 pixel.
 *
 * @type number
 * @name pv.Rule.prototype.lineWidth
 */

/**
 * The style of stroked lines; used in conjunction with <tt>lineWidth</tt> to
 * stroke the rule. The default value of this property is black.
 *
 * @type string
 * @name pv.Rule.prototype.strokeStyle
 * @see pv.color
 */

/**
 * Default properties for rules. By default, a single-pixel black line is
 * stroked.
 *
 * @type pv.Rule
 */
pv.Rule.prototype.defaults = new pv.Rule()
    .extend(pv.Mark.prototype.defaults)
    .lineWidth(1)
    .strokeStyle("black")
    .antialias(false);

/**
 * Constructs a new rule anchor with default properties. Rules support five
 * different anchors:<ul>
 *
 * <li>top
 * <li>left
 * <li>center
 * <li>bottom
 * <li>right
 *
 * </ul>In addition to positioning properties (left, right, top bottom), the
 * anchors support text rendering properties (text-align, text-baseline). Text is
 * rendered to appear outside the rule. Note that this behavior is different
 * from other mark anchors, which default to rendering text <i>inside</i> the
 * mark.
 *
 * <p>For consistency with the other mark types, the anchor positions are
 * defined in terms of their opposite edge. For example, the top anchor defines
 * the bottom property, such that a bar added to the top anchor grows upward.
 *
 * @param {string} name the anchor name; either a string or a property function.
 * @returns {pv.Anchor}
 */
pv.Rule.prototype.anchor = pv.Line.prototype.anchor;

/** @private Sets width or height based on orientation. */
pv.Rule.prototype.buildImplied = function(s) {
  var l = s.left, r = s.right, t = s.top, b = s.bottom;

  /* Determine horizontal or vertical orientation. */
  if ((s.width != null)
      || ((l == null) && (r == null))
      || ((r != null) && (l != null))) {
    s.height = 0;
  } else {
    s.width = 0;
  }

  pv.Mark.prototype.buildImplied.call(this, s);
};