<?php
/**
 * SVG base gradient abstract class
 *
 * @author     Nicolas Perriault <nperriault@gmail.com>
 * @package    cleversvg
 * @subpackage gradients
 */
class csBaseGradient extends csBaseElement
{

  protected
    $stops         = array(),
    $xml_node_name = 'unknown';

  /**
   * Adds a &lt;stop/&gt; elementto specify gradient marker points
   *
   * @param  mixed   $offset       Stop offset (can be percentage)
   * @param  string  $stop_color   (optional, default=black)
   * @param  string  $stop_opacity (optional, default=1)
   */
  public function addStop($offset, $stop_color='black', $stop_opacity=1)
  {
    $this->stops[] = array('offset'       => $offset,
                           'stop-color'   => $stop_color,
                           'stop-opacity' => $stop_opacity);
  }

  /**
   * Computes DOMXML Node
   *
   * @param  boolean  $embedded  Is SVG element embedded ?
   * @return DOMElement
   */
  public function compile($embedded=false)
  {
    $dom = $this->getDomDocument();
    $element_node = parent::compile($embedded);

    // Add stops
    if (count($this->stops) > 0)
    {
      foreach ($this->stops as $stop)
      {
        $stop_node = $dom->createElement($this->getStopNodeName($embedded));
        foreach ($stop as $attr_name => $attr_value)
        {
          $stop_node->setAttribute($attr_name, $attr_value);
        }
        $element_node->appendChild($stop_node);
      }
    }

    return $element_node;
  }

  /**
   * Gets the node name of current SVG element
   *
   * @param  boolean  $embedded
   * @return string
   */
  protected function getStopNodeName($embedded)
  {
    return $embedded === true ? 'svg:stop' : 'stop';
  }

}