PHP – Auto Generate a Photo Gallery from a Directory with pagination

Three year ago I wrote a post on generating image gallery from a given directory. Some of my readers are requested to add pagination to gallery so I have decided to take his tutorial a step further by showing you how to generate pagination for the gallery using PHP.

Creating an photo gallery from a folder or directory of images using PHP is easy. I have added inline comments for each code block, just go through them for better understanding.

isFile() && in_array($fileinfo->getExtension(),array('jpg','png'))) { 
      array_push($allImages,$image_dir.$fileinfo->getBasename());
    }
  }

// total number of images
$total_pages = count($allImages);
	
//how many items to show per page
$page = isset($_GET['page']) ? $_GET['page'] : 1;

//  if no page var is given, set start to 0
$start = $page ?  (($page - 1) * $limit) : 0; 

	
$images = array_slice( $allImages, $start, $limit );;

/* Setup page vars for display. */
if ($page == 0) $page = 1;					//if no page var is given, default to 1.
$prev = $page - 1;							//previous page is page - 1
$next = $page + 1;							//next page is page + 1
$lastpage = ceil($total_pages/$limit);		//lastpage is = total pages / items per page, rounded up.
$lpm1 = $lastpage - 1;						//last page minus 1
	
$pagination = "";
if($lastpage > 1)
{	
  $pagination .= "
";
  //previous button
  if ($page > 1) 
    $pagination.= "Previous";
  else
    $pagination.= "Previous";	
  
  //pages	
  if ($lastpage < 7 + ($adjacents * 2))	//not enough pages to bother breaking it up
  {	
    for ($counter = 1; $counter <= $lastpage; $counter++)
    {
      if ($counter == $page)
        $pagination.= "$counter";
      else
        $pagination.= "$counter";					
    }
  }
  elseif($lastpage > 5 + ($adjacents * 2))	//enough pages to hide some
  {
    //close to beginning; only hide later pages
    if($page < 1 + ($adjacents * 2))		
    {
      for ($counter = 1; $counter < 4 + ($adjacents * 2); $counter++)
      {
        if ($counter == $page)
          $pagination.= "$counter";
        else
          $pagination.= "$counter";					
      }
      $pagination.= "...";
      $pagination.= "$lpm1";
      $pagination.= "$lastpage";		
    }
    //in middle; hide some front and some back
    elseif($lastpage - ($adjacents * 2) > $page && $page > ($adjacents * 2))
    {
      $pagination.= "1";
      $pagination.= "2";
      $pagination.= "...";
      for ($counter = $page - $adjacents; $counter <= $page + $adjacents; $counter++)
      {
        if ($counter == $page)
          $pagination.= "$counter";
        else
          $pagination.= "$counter";					
      }
      $pagination.= "...";
      $pagination.= "$lpm1";
      $pagination.= "$lastpage";		
    }
    //close to end; only hide early pages
    else
    {
      $pagination.= "1";
      $pagination.= "2";
      $pagination.= "...";
      for ($counter = $lastpage - (2 + ($adjacents * 2)); $counter <= $lastpage; $counter++)
      {
        if ($counter == $page)
          $pagination.= "$counter";
        else
          $pagination.= "$counter";					
      }
    }
  }
  
  //next button
  if ($page < $counter - 1) 
    $pagination.= "Next";
  else
    $pagination.= "Next";
  $pagination.= "
\n";		
}

if(count($images) > 0) {
  foreach($images as $image) { ?>