Smarty html_image vertical align image - smarty

Question

We currently use the {html_image file='pumpkin.jpg'} which calculates the width/height of a image.
What I would like to do is add an extra parameter to the function so you can pass in the container(parent) height.
The plugin would then calculate the margin-top by calculating: (container_height - image_height) / 2
At the moment we are doing this by JS and because the images are resized dynamically there is a slight delay. If we did this via Smarty the margin-top would be cached.
As an example if the image [foo.jpg] was 50px height and the container height was 100px:
{html_image file="images/foo.jpg" containerHeight=100}
<img src="images/foo.jpg" width="60" height="50" style="margin-top: 25px" alt="" />
http://www.smarty.net/docs/en/language.function.html.image.tpl
<?php
/**
* Smarty plugin
*
* #package Smarty
* #subpackage PluginsFunction
*/
/**
* Smarty {html_image} function plugin
*
* Type: function<br>
* Name: html_image<br>
* Date: Feb 24, 2003<br>
* Purpose: format HTML tags for the image<br>
* Examples: {html_image file="/images/masthead.gif"}
* Output: <img src="/images/masthead.gif" width=400 height=23>
*
* #link http://smarty.php.net/manual/en/language.function.html.image.php {html_image}
* (Smarty online manual)
* #author Monte Ohrt <monte at ohrt dot com>
* #author credits to Duda <duda#big.hu>
* #version 1.0
* #param array $params parameters
* Input:<br>
* - file = file (and path) of image (required)
* - height = image height (optional, default actual height)
* - width = image width (optional, default actual width)
* - basedir = base directory for absolute paths, default
* is environment variable DOCUMENT_ROOT
* - path_prefix = prefix for path output (optional, default empty)
* #param object $template template object
* #return string
* #uses smarty_function_escape_special_chars()
*/
function smarty_function_html_image($params, $template)
{
require_once(SMARTY_PLUGINS_DIR . 'shared.escape_special_chars.php');
$alt = '';
$file = '';
$height = '';
$width = '';
$extra = '';
$prefix = '';
$suffix = '';
$path_prefix = '';
$server_vars = $_SERVER;
$basedir = isset($server_vars['DOCUMENT_ROOT']) ? $server_vars['DOCUMENT_ROOT'] : '';
foreach($params as $_key => $_val) {
switch ($_key) {
case 'file':
case 'height':
case 'width':
case 'dpi':
case 'path_prefix':
case 'basedir':
$$_key = $_val;
break;
case 'alt':
if (!is_array($_val)) {
$$_key = smarty_function_escape_special_chars($_val);
} else {
throw new SmartyException ("html_image: extra attribute '$_key' cannot be an array", E_USER_NOTICE);
}
break;
case 'link':
case 'href':
$prefix = '<a href="' . $_val . '">';
$suffix = '</a>';
break;
default:
if (!is_array($_val)) {
$extra .= ' ' . $_key . '="' . smarty_function_escape_special_chars($_val) . '"';
} else {
throw new SmartyException ("html_image: extra attribute '$_key' cannot be an array", E_USER_NOTICE);
}
break;
}
}
if (empty($file)) {
trigger_error("html_image: missing 'file' parameter", E_USER_NOTICE);
return;
}
if (substr($file, 0, 1) == '/') {
$_image_path = $basedir . $file;
} else {
$_image_path = $file;
}
if (!isset($params['width']) || !isset($params['height'])) {
if (!$_image_data = #getimagesize($_image_path)) {
if (!file_exists($_image_path)) {
trigger_error("html_image: unable to find '$_image_path'", E_USER_NOTICE);
return;
} else if (!is_readable($_image_path)) {
trigger_error("html_image: unable to read '$_image_path'", E_USER_NOTICE);
return;
} else {
trigger_error("html_image: '$_image_path' is not a valid image file", E_USER_NOTICE);
return;
}
}
if (isset($template->security_policy)) {
if (!$template->security_policy->isTrustedResourceDir($_image_path)) {
return;
}
}
if (!isset($params['width'])) {
$width = $_image_data[0];
}
if (!isset($params['height'])) {
$height = $_image_data[1];
}
}
if (isset($params['dpi'])) {
if (strstr($server_vars['HTTP_USER_AGENT'], 'Mac')) {
$dpi_default = 72;
} else {
$dpi_default = 96;
}
$_resize = $dpi_default / $params['dpi'];
$width = round($width * $_resize);
$height = round($height * $_resize);
}
return $prefix . '<img src="' . $path_prefix . $file . '" alt="' . $alt . '" width="' . $width . '" height="' . $height . '"' . $extra . ' />' . $suffix;
}
?>

Answer 1

Try to add this before the plugin function return statement:
if (isset($params['containerHeight'])) {
$containerHeightAttr = ' style="margin-top: ' . intval(($params['containerHeight'] - $height) / 2) . 'px;"';
$extra .= $containerHeightAttr;
}
Here the full file:
http://pastebin.com/raw.php?i=V9eGsXVF
Try it and let me know if there are errors. I've not tested it, but i'm here to eventually fix problems.