Wordpress: Post lists base on category

gistfile1.txt

/* Posts List base on category*/
function imediapixel_postslist($category, $num, $orderby="date",$style="2col") {  
  global $post;
  
  $category_id = get_cat_ID($category);
  
  $cat_num = ($num) ? $num : 4;
  $counter = 0;
  $out = "";
  query_posts('cat='.$category_id.'&showposts='.$cat_num.'&orderby='.$orderby);
  
  while (have_posts()) : the_post();
    $counter++;
    
    if ($style == "2col") {
      if ($counter %2 ==0) {
        $out .= '<div class="mainbox box-last">'; 
      } else {
        $out .= '<div class="mainbox">';
      }
      $out .= '<h4><a href="'.get_permalink().'">'.get_the_title().'</a></h4>';
      $out .= '<div class="boximg">';
      if (function_exists('has_post_thumbnail') && has_post_thumbnail()) {
        $out .= '<img src="'.get_template_directory_uri().'/timthumb.php?src='.thumb_url().'&amp;h=84&amp;w=84&amp;zc=1" alt="" class="boximg-pad" />'."\n";
      }
      $out .= '</div>';
      $out .= '<p>'.excerpt(25).'</p>';
      $out .= '<a href="'.get_permalink().'" class="button"><span>'.__('VIEW MORE DETAIL ','ecobiz').'<img src="'.get_template_directory_uri().'/images/arrow_grey.png" alt="" class="readmore"/></span></a>';
      $out .= '</div>';         
      if ($counter %2 ==0) {
        $out .= '<div class="spacer"></div>'; 
      }      
    } else if ($style == "3col"){
     if ($counter %3 ==0) {
        $out .= '<div class="mainbox2 box-last">'; 
      } else {
        $out .= '<div class="mainbox2">';
      }
      $out .= '<h4><a href="'.get_permalink().'">'.get_the_title().'</a></h4>';
      $out .= '<div class="boximg2">';
      if (function_exists('has_post_thumbnail') && has_post_thumbnail()) {
        $out .= '<img src="'.get_template_directory_uri().'/timthumb.php?src='.thumb_url().'&amp;h=78&amp;w=182&amp;zc=1" alt="" class="boximg-pad" />'."\n";
      }
      $out .= '</div>';
      $out .= '<p>'.excerpt(8).'</p>';
      $out .= '<a href="'.get_permalink().'" class="button"><span>'.__('VIEW MORE DETAIL ','ecobiz').'<img src="'.get_template_directory_uri().'/images/arrow_grey.png" alt="" class="readmore"/></span></a>';
      $out .= '</div>';         
      if ($counter %3 ==0) {
        $out .= '<div class="spacer"></div>'; 
      } 
    }
    endwhile;
    wp_reset_query();
  return $out;
}

/* ======================================
   Post list base on category
   [postlist $category, $num, $orderby="date",$style="2col"]
   ======================================*/
function imediapixel_postlist_shortcode($atts,$content=null) {
  global $post;
  
  extract(shortcode_atts(array(
    "category" => '',
    "num" => '',
    "orderby" => '',
    "style" => ''
  ),$atts));
  
  if ($style == "") $style = "2col";
  if ($orderby == "") $orderby = "date";
  return imediapixel_postslist($category, $num, $orderby,$style);
}
add_shortcode('postlist','imediapixel_postlist_shortcode');