<?php
  /**
   * @package php-font-lib
   * @link    http://php-font-lib.googlecode.com/
   * @author  Fabien Ménager <fabien.menager@gmail.com>
   * @license http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
   * @version $Id: font_table_hmtx.cls.php 40 2012-01-22 21:48:41Z fabien.menager $
   */
  
  /**
   * `hmtx` font table.
   * 
   * @package php-font-lib
   */
  class Font_Table_hmtx extends Font_Table {
    protected function _parse(){
      $font = $this->getFont();
      $offset = $font->pos();
      
      $numOfLongHorMetrics = $font->getData("hhea", "numOfLongHorMetrics");
      $numGlyphs = $font->getData("maxp", "numGlyphs");
      
      $font->seek($offset);
      
      $data = array();
      for($gid = 0; $gid < $numOfLongHorMetrics; $gid++) {
        $advanceWidth = $font->readUInt16();
        $leftSideBearing = $font->readUInt16();
        $data[$gid] = array($advanceWidth, $leftSideBearing);
      }
      
      if($numOfLongHorMetrics < $numGlyphs){
        $lastWidth = end($data);
        $data = array_pad($data, $numGlyphs, $lastWidth);
      }
      
      $this->data = $data;
    }
    
    protected function _encode() {
      $font = $this->getFont();
      $subset = $font->getSubset();
      $data = $this->data;
      
      $length = 0;
      
      foreach($subset as $gid) {
        $length += $font->writeUInt16($data[$gid][0]);
        $length += $font->writeUInt16($data[$gid][1]);
      }
      
      return $length;
    }
  }