text: <?php
  
  /**
   * @file
   * Hooks provided by the Field UI module.
   */
  
  /**
   * @addtogroup field_types
   * @{
   */
  
  /**
   * Add settings to a field settings form.
   *
   * Invoked from field_ui_field_settings_form() to allow the module defining the
   * field to add global settings (i.e. settings that do not depend on the bundle
   * or instance) to the field settings form. If the field already has data, only
   * include settings that are safe to change.
   *
   * @todo: Only the field type module knows which settings will affect the
   * field's schema, but only the field storage module knows what schema
   * changes are permitted once a field already has data. Probably we need an
   * easy way for a field type module to ask whether an update to a new schema
   * will be allowed without having to build up a fake $prior_field structure
   * for hook_field_update_forbid().
   *
   * @param $field
   *   The field structure being configured.
   * @param $instance
   *   The instance structure being configured.
   * @param $has_data
   *   TRUE if the field already has data, FALSE if not.
   *
   * @return
   *   The form definition for the field settings.
   */
  function hook_field_settings_form($field, $instance, $has_data) {
    $settings = $field['settings'];
    $form['max_length'] = array(
      '#type' => 'textfield',
      '#title' => t('Maximum length'),
      '#default_value' => $settings['max_length'],
      '#required' => FALSE,
      '#element_validate' => array('element_validate_integer_positive'),
      '#description' => t('The maximum length of the field in characters. Leave blank for an unlimited size.'),
    );
    return $form;
  }
  
  /**
   * Add settings to an instance field settings form.
   *
   * Invoked from field_ui_field_edit_form() to allow the module defining the
   * field to add settings for a field instance.
   *
   * @param $field
   *   The field structure being configured.
   * @param $instance
   *   The instance structure being configured.
   *
   * @return
   *   The form definition for the field instance settings.
   */
  function hook_field_instance_settings_form($field, $instance) {
    $settings = $instance['settings'];
  
    $form['text_processing'] = array(
      '#type' => 'radios',
      '#title' => t('Text processing'),
      '#default_value' => $settings['text_processing'],
      '#options' => array(
        t('Plain text'),
        t('Filtered text (user selects text format)'),
      ),
    );
    if ($field['type'] == 'text_with_summary') {
      $form['display_summary'] = array(
        '#type' => 'select',
        '#title' => t('Display summary'),
        '#options' => array(
          t('No'),
          t('Yes'),
        ),
        '#description' => t('Display the summary to allow the user to input a summary value. Hide the summary to automatically fill it with a trimmed portion from the main post.'),
        '#default_value' => !empty($settings['display_summary']) ? $settings['display_summary'] :  0,
      );
    }
  
    return $form;
  }
  
  /**
   * Add settings to a widget settings form.
   *
   * Invoked from field_ui_field_edit_form() to allow the module defining the
   * widget to add settings for a widget instance.
   *
   * @param $field
   *   The field structure being configured.
   * @param $instance
   *   The instance structure being configured.
   *
   * @return
   *   The form definition for the widget settings.
   */
  function hook_field_widget_settings_form($field, $instance) {
    $widget = $instance['widget'];
    $settings = $widget['settings'];
  
    if ($widget['type'] == 'text_textfield') {
      $form['size'] = array(
        '#type' => 'textfield',
        '#title' => t('Size of textfield'),
        '#default_value' => $settings['size'],
        '#element_validate' => array('element_validate_integer_positive'),
        '#required' => TRUE,
      );
    }
    else {
      $form['rows'] = array(
        '#type' => 'textfield',
        '#title' => t('Rows'),
        '#default_value' => $settings['rows'],
        '#element_validate' => array('element_validate_integer_positive'),
        '#required' => TRUE,
      );
    }
  
    return $form;
  }
  
  
  /**
   * Specify the form elements for a formatter's settings.
   *
   * This hook is only invoked if hook_field_formatter_settings_summary()
   * returns a non-empty value.
   *
   * @param $field
   *   The field structure being configured.
   * @param $instance
   *   The instance structure being configured.
   * @param $view_mode
   *   The view mode being configured.
   * @param $form
   *   The (entire) configuration form array, which will usually have no use here.
   * @param $form_state
   *   The form state of the (entire) configuration form.
   *
   * @return
   *   The form elements for the formatter settings.
   */
  function hook_field_formatter_settings_form($field, $instance, $view_mode, $form, &$form_state) {
    $display = $instance['display'][$view_mode];
    $settings = $display['settings'];
  
    $element = array();
  
    if ($display['type'] == 'text_trimmed' || $display['type'] == 'text_summary_or_trimmed') {
      $element['trim_length'] = array(
        '#title' => t('Length'),
        '#type' => 'textfield',
        '#size' => 20,
        '#default_value' => $settings['trim_length'],
        '#element_validate' => array('element_validate_integer_positive'),
        '#required' => TRUE,
      );
    }
  
    return $element;
  
  }
  
  /**
   * Return a short summary for the current formatter settings of an instance.
   *
   * If an empty result is returned, the formatter is assumed to have no
   * configurable settings, and no UI will be provided to display a settings
   * form.
   *
   * @param $field
   *   The field structure.
   * @param $instance
   *   The instance structure.
   * @param $view_mode
   *   The view mode for which a settings summary is requested.
   *
   * @return
   *   A string containing a short summary of the formatter settings.
   */
  function hook_field_formatter_settings_summary($field, $instance, $view_mode) {
    $display = $instance['display'][$view_mode];
    $settings = $display['settings'];
  
    $summary = '';
  
    if ($display['type'] == 'text_trimmed' || $display['type'] == 'text_summary_or_trimmed') {
      $summary = t('Length: @chars chars', array('@chars' => $settings['trim_length']));
    }
  
    return $summary;
  }
  
  /**
   * @} End of "addtogroup field_types".
   */
  