simple_icons.module

<?php

function simple_icons_init() {
    	define('FILES_DIR', 'sites/default/files'); 
	define('ICONS_DIR', drupal_get_path('module', 'simple_icons') . "/" . 'icons');
}

function simple_icons_icon($value, $type="png") {
	/*************************************
	*
	* General purpose: return an image name corresponding to the select value
	* For more detailed implementations this function could be changed
	*
	*************************************/
	return ICONS_DIR . "/" . $value . "." . $type;
}

/**
* Implements hook_field_formatter_info().
*/
function simple_icons_field_formatter_info() {
  $info = array(
    'simple_icons_icon' => array(
      'label' => t('Simple Icons'), 
      'field types' => array('list_text'),
      'description' => t('Displays an icon instead of text for a select list.'),
      'settings' => array(
        'link' => 0,
	   'wrapper' => 'div',
      ),
    ), 
  );
  return $info;
}

/**
 * Implements hook_field_formatter_settings_form().
 */
function simple_icons_field_formatter_settings_form($field, $instance, $view_mode, $form, &$form_state) {
  $display = $instance['display'][$view_mode];
  $settings = $display['settings'];

  $element['link'] = array(
    '#title' => t('Link to content'),
    '#type' => 'checkbox',
    '#default_value' => $settings['link'],
  );

  $element['wrapper'] = array(
    '#title' => t('Wrapper'),
    '#type' => 'select',
    '#options' => array('div'=>'div', 'span'=>'span', 'none'=>'none'),
    '#default_value' => $settings['wrapper'],
  );

  return $element;
}

/**
 * Implements hook_field_formatter_settings_summary().
 */
function simple_icons_field_formatter_settings_summary($field, $instance, $view_mode) {
  	$display = $instance['display'][$view_mode];
  	$settings = $display['settings'];

  	$summary = 'Link to content: ' . ($settings['link'] == 1 ? 'YES' : 'NO');
	$summary .= '<br />Wrapper: ' . $settings['wrapper'];
  	return $summary;
}

/**
* Implements hook_field_formatter_view().
*/
function simple_icons_field_formatter_view($entity_type, $entity, $field, $instance, $langcode, $items, $display) {
	$settings = $display['settings'];
  	$element = array();
	$curi = entity_uri($entity_type, $entity);
	$content_path = $curi['path'];

	  switch ($display['type']) {
	    case 'simple_icons_icon':
		$allowed_values = list_allowed_values($field, $instance, $entity_type, $entity);
		 foreach ($items as $delta => $item) {
		   if (isset($allowed_values[$item['value']])) {
		     $alt = field_filter_xss($allowed_values[$item['value']]);
		   }
		   else {
		     // If no match was found in allowed values, fall back to the key.
		     $alt = field_filter_xss($item['value']);
		   }
			$val = field_filter_xss($item['value']);
		   $element[$delta] = array(
		     '#theme' => 'simple_icons_icon', 
		     '#alt' => $alt, 
		     '#icon' => simple_icons_icon($val), 
			'#link' => $settings['link'],
			'#cpath' => $content_path,
			'#wrapper' => $settings['wrapper'],
		   );
		 }
		 break;
	  }
	  return $element;
}

/**
* Implements hook_theme().
*/
function simple_icons_theme() {
  return array(
    'simple_icons_icon' => array(
      'template' => 'simple_icons_icon',
      'variables' => array(
        'alt' => NULL,
        'icon' => NULL,
	   'link' => NULL,
	   'cpath' => NULL,
	   'wrapper' => NULL,
      ),
	'path' => drupal_get_path('module', 'simple_icons'),
    ),
  );
}