ais.module in Adaptive Image Styles (ais) 7

Adaptive Image Styles Module

File

ais.module

<?php

/**
 * @file
 * Adaptive Image Styles Module
 *
 */
define("AIS_ADAPTIVE_STYLE", 'adaptive');
define("AIS_ADAPTIVE_CLASS", 'adaptive');

/**
 * Implements hook_js_alter().
 *  Loads the Adaptive javascript as early as possible
 */
function ais_js_alter(&$javascript) {
  $ais = variable_get("ais_adaptive_styles", array());
  usort($ais, "_ais_cmp_styles");
  $javascript[] = array(
    'browsers' => array(),
    'type' => 'inline',
    'every_page' => 1,
    'group' => 0,
    'weight' => 0,
    'scope' => 'header',
    'cache' => 1,
    'defer' => NULL,
    'preprocess' => 1,
    'version' => NULL,
    'data' => "Drupal.settings.ais = " . drupal_json_encode($ais) . ";\nDrupal.settings.ais_method = \"" . variable_get("ais_adaptive_styles_method", 'both-max') . "\";",
  );
  $javascript['ais/assets/js/ais.js'] = array(
    'browsers' => array(),
    'weight' => 1,
    'type' => 'file',
    'group' => 0,
    'every_page' => 1,
    'scope' => 'header',
    'cache' => 1,
    'defer' => NULL,
    'preprocess' => 1,
    'version' => NULL,
    'data' => drupal_get_path('module', 'ais') . '/assets/js/ais.js',
  );
}

/**
 * Implements hook_permission().
 */
function ais_permission() {
  return array(
    'administer ais' => array(
      'title' => t('Administer Adaptive Image Styles'),
      'description' => t('Configure which images styles are used as adaptive.'),
    ),
  );
}

/**
 * Implements hook_menu().
 */
function ais_menu() {
  $items = array();
  $items['admin/config/media/ais'] = array(
    'title' => 'Adaptive Image Styles',
    'description' => 'Configure when adaptive image style are used.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array(
      'ais_admin_settings',
    ),
    'access arguments' => array(
      'administer ais',
    ),
    'file' => 'ais.admin.inc',
  );
  return $items;
}

/**
 * Implements hook_menu_alter().
 */
function ais_menu_alter(&$items) {

  // Find all page callbacks that use image_style_deliver() (including the ones
  // for public and private image styles defined by the Image module in Drupal
  // core) and replace them with a new one that handles adaptive image styles.
  foreach ($items as &$item) {
    if (isset($item['page callback']) && $item['page callback'] == 'image_style_deliver') {
      $item['page callback'] = 'ais_image_style_deliver';
    }
  }
}

/**
 * Wrapper for image_style_deliver() that handles adaptive image styles.
 */
function ais_image_style_deliver($style, $scheme) {
  $args = func_get_args();
  array_shift($args);
  array_shift($args);
  $target = implode('/', $args);

  // By design, this module allows HTTP clients to switch between different
  // adaptive image styles for the same image. Therefore, if the request has
  // the correct security token for the main adaptive style, we can safely
  // deliver any other adaptive style also.
  $bypass_granted = FALSE;
  if (!variable_get('image_allow_insecure_derivatives', FALSE) && defined('IMAGE_DERIVATIVE_TOKEN')) {

    // First check that an adaptive style is being requested.
    $styles = variable_get('ais_adaptive_styles', array());
    $bypass = isset($style['name']) && _ais_is_used($style['name'], $styles);

    // Next check that a valid token for the main adaptive style is present.
    $bypass = $bypass && isset($_GET[IMAGE_DERIVATIVE_TOKEN]) && $_GET[IMAGE_DERIVATIVE_TOKEN] === image_style_path_token(AIS_ADAPTIVE_STYLE, $scheme . '://' . $target);

    // If so, we can bypass the standard image_style_deliver() security check
    // for this request.
    if ($bypass) {
      $bypass_granted = TRUE;
      $GLOBALS['conf']['image_allow_insecure_derivatives'] = TRUE;
    }
  }

  // Execute the standard page callback.
  $func_args = func_get_args();
  $return = call_user_func_array('image_style_deliver', $func_args);

  // Before returning, reset the 'image_allow_insecure_derivatives' variable if
  // we changed it above.
  if ($bypass_granted) {
    $GLOBALS['conf']['image_allow_insecure_derivatives'] = FALSE;
  }
  return $return;
}

/**
 * Implements hook_image_default_styles().
 */
function ais_image_default_styles() {
  $styles = array();
  $styles['adaptive'] = array(
    'effects' => array(),
  );
  $styles['threshold-480'] = array(
    'effects' => array(
      array(
        'name' => 'image_scale',
        'data' => array(
          'width' => 480,
          'height' => 480,
          'upscale' => 0,
        ),
        'weight' => 0,
      ),
    ),
  );
  $styles['threshold-768'] = array(
    'effects' => array(
      array(
        'name' => 'image_scale',
        'data' => array(
          'width' => 768,
          'height' => 768,
          'upscale' => 0,
        ),
        'weight' => 0,
      ),
    ),
  );
  $styles['threshold-992'] = array(
    'effects' => array(
      array(
        'name' => 'image_scale',
        'data' => array(
          'width' => 992,
          'height' => 992,
          'upscale' => 0,
        ),
        'weight' => 0,
      ),
    ),
  );
  $styles['threshold-1382'] = array(
    'effects' => array(
      array(
        'name' => 'image_scale',
        'data' => array(
          'width' => 1382,
          'height' => 1382,
          'upscale' => 0,
        ),
        'weight' => 0,
      ),
    ),
  );
  return $styles;
}

/**
 * Implements hook_file_default_displays().
 *
 * Provides default display configurations for media types.
 *
 * @see file_entity_schema()
 */
function ais_file_default_displays() {
  $default_displays = array();
  $default_image_styles = array(
    'media_adaptive' => 'adaptive',
  );
  foreach ($default_image_styles as $view_mode => $image_style) {
    $display_name = 'image__' . $view_mode . '__file_image';
    $default_displays[$display_name] = (object) array(
      'api_version' => 1,
      'name' => $display_name,
      'status' => 1,
      'weight' => 5,
      'settings' => array(
        'image_style' => $image_style,
      ),
    );
  }
  return $default_displays;
}

/**
 * Implements hook_ctools_plugin_api().
 *
 * Lets CTools know which plugin APIs are implemented by Media module.
 */
function ais_ctools_plugin_api($owner, $api) {
  static $api_versions = array(
    'file_entity' => array(
      'file_default_displays' => 1,
    ),
  );
  if (isset($api_versions[$owner][$api])) {
    return array(
      'version' => $api_versions[$owner][$api],
    );
  }
}

/**
 * Implements hook_entity_info_alter().
 *
 * Add view modes to the file entity type, appropriate for displaying media.
 */
function ais_entity_info_alter(&$entity_info) {
  $entity_info['file']['view modes']['media_adaptive'] = array(
    'label' => t('Adaptive'),
    'custom settings' => TRUE,
  );
}

/**
 * Checks if the given image styles is set to be adaptive
 *
 * @param string $image_style
 *   Machine name of an image style
 *
 * @return boolean
 *   Returns TRUE if the image style is adaptive, FALSE otherwise.
 */
function ais_is_adaptive_style($image_style) {
  return $image_style == AIS_ADAPTIVE_STYLE;
}

/**
 * Implements template_preprocess_image().
 *
 * Adds a class to adaptive images for max-width.
 */
function ais_preprocess_image(&$variables) {
  if (isset($variables['style_name'])) {
    if (ais_is_adaptive_style($variables['style_name'])) {
      if (!isset($variables['attributes']['class'])) {
        $variables['attributes']['class'] = array();
      }
      elseif (!is_array($variables['attributes']['class'])) {
        $variables['attributes']['class'] = array(
          $variables['attributes']['class'],
        );
      }
      $variables['attributes']['class'][] = AIS_ADAPTIVE_CLASS;
    }
  }
}

/**
 * Implements hook_help().
 */
function ais_help($path, $arg) {
  switch ($path) {
    case 'admin/help#ais':
      return '<p>' . t('The adaptive image styles module offers an easy way to make any images adaptive.  Simply choosing to display the image with the "adaptive" image style with make the image adapt to the clients window width.  The <a href="@aissettings">Adaptive Image Styles administration page</a> provides an interface for choosing which image styles are using to generate the adapted images and set the threshold for when they are chosen.', array(
        '@aissettings' => url('admin/config/media/ais'),
      )) . '</p>';
    case 'admin/config/media/ais':
      return '<p>' . t('This page provides a interface for choosing which image style generate the adapted images.  The threshold for when each style is used can also be set.  The threshold refers to browser window width.') . '</p><p>' . t('Example: If there are three image style selected, with thresholds of 480, 768, and 992.  If the window width is from 0 - 480 pixels, the adaptive image will be displayed using the image style with a threshold of 480.  From 481 - 768, the 768 image style will be used, and any wider than 769, the image style with the threshold of 992 will be used.') . '</p>';
  }
}

/**
 * Checks the given array for the given image style
 *
 * @param string $name
 *   Machine name of the image style
 * @param array $ais
 *   Array of image styles
 *
 * @return boolean
 *   Return TRUE if it is in the array, FALSE otherwise.
 */
function _ais_is_used($name, &$ais) {
  foreach ($ais as $is) {
    if ($is['name'] == $name) {
      return TRUE;
    }
  }
  return FALSE;
}

/**
 * Loads the size saved in the array
 *
 * @param string $name
 *   Machine name of the image style
 * @param array $ais
 *   Array of image styles
 *
 * @return integer
 *   Returns the max size, default is zero (0).
 */
function _ais_get_size($name, &$ais) {
  foreach ($ais as $is) {
    if ($is['name'] == $name) {
      return $is['size'];
    }
  }
  return 0;
}

/**
 * Cmp function for style sort.
 * @see http://www.php.net/manual/en/function.usort.php
 */
function _ais_cmp_styles($a, $b) {
  if ($a['size'] == $b['size']) {
    return 0;
  }
  return $a['size'] < $b['size'] ? -1 : 1;
}

Functions

Name	Description
ais_ctools_plugin_api	Implements hook_ctools_plugin_api().
ais_entity_info_alter	Implements hook_entity_info_alter().
ais_file_default_displays	Implements hook_file_default_displays().
ais_help	Implements hook_help().
ais_image_default_styles	Implements hook_image_default_styles().
ais_image_style_deliver	Wrapper for image_style_deliver() that handles adaptive image styles.
ais_is_adaptive_style	Checks if the given image styles is set to be adaptive
ais_js_alter	Implements hook_js_alter(). Loads the Adaptive javascript as early as possible
ais_menu	Implements hook_menu().
ais_menu_alter	Implements hook_menu_alter().
ais_permission	Implements hook_permission().
ais_preprocess_image	Implements template_preprocess_image().
_ais_cmp_styles	Cmp function for style sort.
_ais_get_size	Loads the size saved in the array
_ais_is_used	Checks the given array for the given image style

Constants

Name	Description
AIS_ADAPTIVE_CLASS
AIS_ADAPTIVE_STYLE	@file Adaptive Image Styles Module