How to obscure email and other text using signwriter and a cck formatter

Here is an example on how to obscure email addresse (or other tekst) using http://drupal.org/project/signwriter in a formatter. You can use it on the cck field overview as a formatter (or in display suite).

<?php
//cck formatters
/**
 * Implementation of hook_field_formatter_info(),.
 */
function your_module_field_formatter_info() {
  return array(
    'text_as_image' => array(
      'label' => t('Text as image'),
      'field types' => array('email', 'text'),
      'multiple values' => CONTENT_HANDLE_MODULE,
    ),
  );
}

/**
 * Implementation of hook_theme().
 */
function your_module_theme() {
  $theme_functions['your_module_formatter_text_as_image'] = array (
    'arguments' => array('element' => NULL),
  );

  return $theme_functions;
}

/**
 * Themes an image from text
 */
function theme_your_module_formatter_text_as_image($element) {
  // Set up signwriter profile    
  $profile->fontfile = drupal_get_path('module', 'signwriter'). '/Arial.TTF';//See this issue why its like this (http://drupal.org/node/606670)
  $profile->fontsize = 10;
  $profile->foreground = '000000';
  $profile->background = 'ffffff';
  $profile->maxwidth = 600;
  $profile->transparent = true;
  $profile->imagetype = 'png';
  $profile->disable_span = true;
  
  $string_to_obscure = $element[0]['#item']['safe']; 
    
  $text= signwriter_title_convert($string_to_obscure, $profile);
  //Some extra logic if it is an email    
  $output = preg_replace('/alt="[0-9a-zA-Z!@#\$%^&\*~\-\.\+\_\/=\?\|\{\}}]+"/','alt="Email Address"',$text);
    
  return $output;
}
?>

The code in the formatter is taken from this example http://dominiquedecooman.com/bookmark/obscure-email-adresses-drupal-usin...

Submitted by Dominique De Cooman on Wed, 2010-08-11 13:19
cck email formatters security spam

For big sites

Submitted by Dominique De Cooman on Wed, 2010-08-11 14:24.

To use signwritter on sites with lots of nodes, meaning lots of images check out this issue http://drupal.org/node/880006

Empty element

Submitted by svdhout (not verified) on Tue, 2010-09-21 10:28.

If the element has no data, this wil create an empty image.
This means the label for this field will always be shown.
You should check for data before you create the image

That indeed correct. A check

Submitted by Dominique De Cooman on Tue, 2010-09-21 12:06.

That indeed correct. A check should be performed. Above function should be.

<?php

/**
 * Themes an image from text
 */
function theme_your_module_formatter_text_as_image($element) {
  //Validation
  $string_to_obscure = $element[0]['#item']['safe'];
  if (!$string_to_obscure) {
    return;
  }

  // Set up signwriter profile    
  $profile->fontfile = drupal_get_path('module', 'signwriter'). '/Arial.TTF';//See this issue why its like this (<a href="http://drupal.org/node/606670" title="http://drupal.org/node/606670">http://drupal.org/node/606670</a>)
  $profile->fontsize = 10;
  $profile->foreground = '000000';
  $profile->background = 'ffffff';
  $profile->maxwidth = 600;
  $profile->transparent = true;
  $profile->imagetype = 'png';
  $profile->disable_span = true; 
    
  $text= signwriter_title_convert($string_to_obscure, $profile);
  //Some extra logic if it is an email    
  $output = preg_replace('/alt="[0-9a-zA-Z!@#\$%^&\*~\-\.\+\_\/=\?\|\{\}}]+"/','alt="Email Address"',$text);
    
  return $output;
}
?>