<?php
// $Id$

/**
 * @file
 * Dynamic image resizer and image cacher.
 *
 * ImageCache allows you to setup presets for image processing.
 * If an ImageCache derivative doesn't exist the web server's
 * rewrite rules will pass the request to Drupal which in turn
 * hands it off to imagecache to dynamically generate the file.
 *
 * To view a derivative image you request a special url containing
 * 'imagecache/<presetname>/path/to/file.ext.
 *
 * Presets can be managed at http://example.com/admin/build/imagecache.
 *
 * To view a derivative image you request a special url containing
 * 'imagecache/<presetname>/path/to/file.ext.
 *
 * If you had a preset names 'thumbnail' and you wanted to see the
 * thumbnail version of  http://example.com/files/path/to/myimage.jpg you
 * would use http://example.com/files/imagecache/thumbnail/path/to/myimage.jpg
 *
 * ImageCache provides formatters for CCK Imagefields and is leveraged by several
 * other modules. ImageCache also relies heavily on ImageAPI for it's image processing.
 * If there are errors with actual image processing look to ImageAPI first.
 *
 * @todo: add watermarking capabilities.
 *
 */

/**
 * Imagecache preset storage constant for user-defined presets in the DB.
 */
define('IMAGECACHE_STORAGE_NORMAL', 0);

/**
 * Imagecache preset storage constant for module-defined presets in code.
 */
define('IMAGECACHE_STORAGE_DEFAULT', 1);

/**
 * Imagecache preset storage constant for user-defined presets that override
 * module-defined presets.
 */
define('IMAGECACHE_STORAGE_OVERRIDE', 2);

/*********************************************************************************************
 * Drupal Hooks
 *********************************************************************************************/

/**
 * Implementation of hook_perm().
 */
function imagecache_perm() {
  $perms =  array('administer imagecache', 'flush imagecache');
  foreach (imagecache_presets() as $preset) {
    $perms[] =  'view imagecache '. $preset['presetname'];
  }
  return $perms;
}

/**
 * Implementation of hook_menu().
 */
function imagecache_menu() {
  $items = array();

  // standard imagecache callback.
  $items[file_directory_path() .'/imagecache'] = array(
    'page callback' => 'imagecache_cache',
    'access callback' => TRUE,
    'type' => MENU_CALLBACK
  );
  // private downloads imagecache callback
  $items['system/files/imagecache'] = array(
    'page callback' => 'imagecache_cache_private',
    'access callback' => TRUE,
    'type' => MENU_CALLBACK
  );

  return $items;
}

/**
 * Clear imagecache presets cache on admin/build/modules form.
 */
function imagecache_form_system_modules_alter(&$form, $form_state) {
  imagecache_presets(TRUE);
}

/**
 * Implementation of hook_theme().
 */
function imagecache_theme() {
  $theme = array(
    'imagecache' => array(
      'arguments' => array(
        'namespace' => NULL,
        'path' => NULL,
        'alt' => NULL,
        'title' => NULL,
    )),
    'imagecache_imagelink' => array(
      'arguments' => array(
        'namespace' => NULL,
        'path' => NULL,
        'alt' => NULL,
        'title' => NULL,
        'attributes' => array(),
    )),
    'imagecache_resize' => array(
      'file' => 'imagecache_actions.inc',
      'arguments' => array('element' => NULL),
    ),
    'imagecache_scale' => array(
      'file' => 'imagecache_actions.inc',
      'arguments' => array('element' => NULL),
    ),
    'imagecache_scale_and_crop' => array(
      'file' => 'imagecache_actions.inc',
      'arguments' => array('element' => NULL),
    ),
    'imagecache_deprecated_scale' => array(
      'file' => 'imagecache_actions.inc',
      'arguments' => array('element' => NULL),
    ),
    'imagecache_crop' => array(
      'file' => 'imagecache_actions.inc',
      'arguments' => array('element' => NULL),
    ),
    'imagecache_desaturate' => array(
      'file' => 'imagecache_actions.inc',
      'arguments' => array('element' => NULL),
    ),
    'imagecache_rotate' => array(
      'file' => 'imagecache_actions.inc',
      'arguments' => array('element' => NULL),
    ),
    'imagecache_sharpen' => array(
      'file' => 'imagecache_actions.inc',
      'arguments' => array('element' => NULL),
    ),
  );

  foreach (imagecache_presets() as $preset) {
    $theme['imagecache_formatter_'. $preset['presetname'] .'_default'] = array(
      'arguments' => array('element' => NULL),
      'function' => 'theme_imagecache_formatter',
    );
    $theme['imagecache_formatter_'. $preset['presetname'] .'_linked'] = array(
      'arguments' => array('element' => NULL),
      'function' => 'theme_imagecache_formatter',
    );
    $theme['imagecache_formatter_'. $preset['presetname'] .'_imagelink'] = array(
      'arguments' => array('element' => NULL),
      'function' => 'theme_imagecache_formatter',
    );
    $theme['imagecache_formatter_'. $preset['presetname'] .'_path'] = array(
      'arguments' => array('element' => NULL),
      'function' => 'theme_imagecache_formatter',
    );
    $theme['imagecache_formatter_'. $preset['presetname'] .'_url'] = array(
      'arguments' => array('element' => NULL),
      'function' => 'theme_imagecache_formatter',
    );
  }

  return $theme;

}

/**
 * Implementation of hook_imagecache_actions.
 *
 * @return array
 *   An array of information on the actions implemented by a module. The array
 *   contains a sub-array for each action node type, with the machine-readable
 *   action name as the key. Each sub-array has up to 3 attributes. Possible
 *   attributes:
 *
 *     "name": the human-readable name of the action. Required.
 *     "description": a brief description of the action. Required.
 *     "file": the name of the include file the action can be found
 *             in relative to the implementing module's path.
 */
function imagecache_imagecache_actions() {
  $actions = array(
    'imagecache_resize' => array(
      'name' => 'Resize',
      'description' => 'Resize an image to an exact set of dimensions, ignoring aspect ratio.',
    ),
    'imagecache_scale' => array(
      'name' => 'Scale',
      'description' => 'Resize an image maintaining the original aspect-ratio (only one value necessary).',
      'file' => 'imagecache_actions.inc',
    ),
    'imagecache_deprecated_scale' => array(
      'name' => 'Deprecated Scale',
      'description' => 'Precursor to Scale and Crop. Has inside and outside dimension support. This action will be removed in ImageCache 2.1).',
      'file' => 'imagecache_actions.inc',
    ),
    'imagecache_scale_and_crop' => array(
      'name' => 'Scale And Crop',
      'description' => 'Resize an image to an exact set of dimensions, ignoring aspect ratio.',
      'file' => 'imagecache_actions.inc',
    ),
    'imagecache_crop' => array(
      'name' => 'Crop',
      'description' => 'Crop an image to the rectangle specified by the given offsets and dimensions.',
      'file' => 'imagecache_actions.inc',
    ),
    'imagecache_desaturate' => array(
      'name' => 'Desaturate',
      'description' => 'Convert an image to grey scale.',
      'file' => 'imagecache_actions.inc',
    ),
    'imagecache_rotate' => array(
      'name' => 'Rotate',
      'description' => 'Rotate an image.',
      'file' => 'imagecache_actions.inc',
    ),
    'imagecache_sharpen' => array(
      'name' => 'Sharpen',
      'description' => 'Sharpen an image using unsharp masking.',
      'file' => 'imagecache_actions.inc',
    ),
  );

  return $actions;
}

/**
 * Pull in actions exposed by other modules using hook_imagecache_actions().
 *
 * @param $reset
 *   Boolean flag indicating whether the cached data should be
 *   wiped and recalculated.
 *
 * @return
 *   An array of actions to be used when transforming images.
 */
function imagecache_action_definitions($reset = FALSE) {
  static $actions;
  if (!isset($actions) || $reset) {
    if (!$reset && ($cache = cache_get('imagecache_actions')) && !empty($cache->data)) {
      $actions = $cache->data;
    }
    else {
      foreach (module_implements('imagecache_actions') as $module) {
        foreach (module_invoke($module, 'imagecache_actions') as $key => $action) {
          $action['module'] = $module;
          if (!empty($action['file'])) {
            $action['file'] = drupal_get_path('module', $action['module']) .'/'. $action['file'];
          }
          $actions[$key] = $action;
        };
      }
      uasort($actions, '_imagecache_definitions_sort');
      cache_set('imagecache_actions', $actions);
    }
  }
  return $actions;
}

function _imagecache_definitions_sort($a, $b) {
  $a = $a['name'];
  $b = $b['name'];
  if ($a == $b) {
    return 0;
  }
  return ($a < $b) ? -1 : 1;
}

function imagecache_action_definition($action) {
  static $definition_cache;
  if (!isset($definition_cache[$action])) {
    $definitions = imagecache_action_definitions();
    $definition = (isset($definitions[$action])) ? $definitions[$action] : array();

    if (isset($definition['file'])) {
      require_once($definition['file']);
    }
    $definition_cache[$action] = $definition;
  }
  return $definition_cache[$action];
}

/**
 * Return a URL that points to the location of a derivative of the
 * original image transformed with the given preset.
 *
 * Special care is taken to make this work with the possible combinations of
 * Clean URLs and public/private downloads. For example, when Clean URLs are not
 * available an URL with query should be returned, like
 * http://example.com/?q=files/imagecache/foo.jpg, so that imagecache is able
 * intercept the request for this file.
 *
 * This code is very similar to the Drupal core function file_create_url(), but
 * handles the case of Clean URLs and public downloads differently however.
 *
 * @param $presetname
 * @param $filepath
 *   String specifying the path to the image file.
 * @param $bypass_browser_cache
 *   A Boolean indicating that the URL for the image should be distinct so that
 *   the visitors browser will not be able to use a previously cached version.
 *   This is
 */
function imagecache_create_url($presetname, $filepath, $bypass_browser_cache = FALSE) {
  $path = _imagecache_strip_file_directory($filepath);
  $args = array('absolute' => TRUE, 'query' => $bypass_browser_cache ? time() : $bypass_browser_cache);
  switch (variable_get('file_downloads', FILE_DOWNLOADS_PUBLIC)) {
    case FILE_DOWNLOADS_PUBLIC:
      return url($GLOBALS['base_url'] . '/' . file_directory_path() .'/imagecache/'. $presetname .'/'. $path, $args);
    case FILE_DOWNLOADS_PRIVATE:
      return url('system/files/imagecache/'. $presetname .'/'. $path, $args);
  }
}

/**
 * Return a file system location that points to the location of a derivative
 * of the original image at @p $path, transformed with the given @p $preset.
 * Keep in mind that the image might not yet exist and won't be created.
 */
function imagecache_create_path($presetname, $path) {
  $path = _imagecache_strip_file_directory($path);
  return file_create_path() .'/imagecache/'. $presetname .'/'. $path;
}

/**
 * Remove a possible leading file directory path from the given path.
 */
function _imagecache_strip_file_directory($path) {
  $dirpath = file_directory_path();
  $dirlen = strlen($dirpath);
  if (substr($path, 0, $dirlen + 1) == $dirpath .'/') {
    $path = substr($path, $dirlen + 1);
  }
  return $path;
}


/**
 * callback for handling public files imagecache requests.
 */
function imagecache_cache() {
  $args = func_get_args();
  $preset = check_plain(array_shift($args));
  $path = implode('/', $args);
  _imagecache_cache($preset, $path);
}

/**
 * callback for handling private files imagecache requests
 */
function imagecache_cache_private() {
  $args = func_get_args();
  $preset = check_plain(array_shift($args));
  $source = implode('/', $args);

  if (user_access('view imagecache '. $preset)) {
    _imagecache_cache($preset, $source);
  }
  else {
    // if there is a 403 image, display it.
    $accesspath = file_create_path('imagecache/'. $preset .'.403.png');
    if (is_file($accesspath)) {
      imagecache_transfer($accesspath);
      exit;
    }
    header('HTTP/1.0 403 Forbidden');
    exit;
  }
}

/**
 * handle request validation and responses to imagecache requests.
 */
function _imagecache_cache($presetname, $path) {
  if (!$preset = imagecache_preset_by_name($presetname)) {
    // Send a 404 if we don't know of a preset.
    header("HTTP/1.0 404 Not Found");
    exit;
  }

  // umm yeah deliver it early if it is there. especially useful
  // to prevent lock files from being created when delivering private files.
  $dst = imagecache_create_path($preset['presetname'], $path);
  if (is_file($dst)) {
    imagecache_transfer($dst);
  }

  // preserve path for watchdog.
  $src = $path;

  // Check if the path to the file exists.
  if (!is_file($src) && !is_file($src = file_create_path($src))) {
    watchdog('imagecache', '404: Unable to find %image ', array('%image' => $src), WATCHDOG_ERROR);
    header("HTTP/1.0 404 Not Found");
    exit;
  };

  // Bail if the requested file isn't an image you can't request .php files
  // etc...
  if (!getimagesize($src)) {
    watchdog('imagecache', '403: File is not an image %image ', array('%image' => $src), WATCHDOG_ERROR);
    header('HTTP/1.0 403 Forbidden');
    exit;
  }

  $lockfile = file_directory_temp() .'/'. $preset['presetname'] . basename($src);
  if (file_exists($lockfile)) {
    watchdog('imagecache', 'ImageCache already generating: %dst, Lock file: %tmp.', array('%dst' => $dst, '%tmp' => $lockfile), WATCHDOG_NOTICE);
    // 307 Temporary Redirect, to myself. Lets hope the image is done next time around.
    header('Location: '. request_uri(), TRUE, 307);
    exit;
  }
  touch($lockfile);
  // register the shtdown function to clean up lock files. by the time shutdown
  // functions are being called the cwd has changed from document root, to
  // server root so absolute paths must be used for files in shutdown functions.
  register_shutdown_function('file_delete', realpath($lockfile));

  // check if deriv exists... (file was created between apaches request handler and reaching this code)
  // otherwise try to create the derivative.
  if (file_exists($dst) || imagecache_build_derivative($preset['actions'], $src, $dst)) {
    imagecache_transfer($dst);
  }
  // Generate an error if image could not generate.
  watchdog('imagecache', 'Failed generating an image from %image using imagecache preset %preset.', array('%image' => $path, '%preset' => $preset['presetname']), WATCHDOG_ERROR);
  header("HTTP/1.0 500 Internal Server Error");
  exit;
}

/**
 * Apply an action to an image.
 *
 * @param $action
 *   Action array
 * @param $image
 *   Image object
 * @return
 *   Boolean, TRUE indicating success and FALSE failure.
 */
function _imagecache_apply_action($action, $image) {
  $actions = imagecache_action_definitions();

  if ($definition = imagecache_action_definition($action['action'])) {
    $function = $action['action'] .'_image';
    if (function_exists($function)) {
      return $function($image, $action['data']);
    }
  }
  // skip undefined actions.. module probably got uninstalled or disabled.
  watchdog('imagecache', 'non-existant action %action', array('%action' => $action['action']), WATCHDOG_NOTICE);
  return TRUE;
}

/**
 * Helper function to transfer files from imagecache.
 *
 * Determines MIME type and sets a last modified header.
 *
 * @param $path
 *   String containing the path to file to be transferred.
 * @return
 *   This function does not return. It calls exit().
 */

function imagecache_transfer($path) {
  $size = getimagesize($path);
  $headers = array('Content-Type: '. mime_header_encode($size['mime']));

  if ($fileinfo = stat($path)) {
    $headers[] = 'Content-Length: '. $fileinfo[7];
    _imagecache_cache_set_cache_headers($fileinfo, $headers);
  }
  file_transfer($path, $headers);
  exit;
}

/**
 * Set file headers that handle "If-Modified-Since" correctly for the
 * given fileinfo.
 *
 * Note that this function may return or may call exit().
 *
 * Most code has been taken from drupal_page_cache_header().
 *
 * @param $fileinfo
 *   Array returned by stat().
 * @param
 *   Array of existing headers.
 * @return
 *   Nothing but beware that this function may not return.
 */
function _imagecache_cache_set_cache_headers($fileinfo, &$headers) {
  // Set default values:
  $last_modified = gmdate('D, d M Y H:i:s', $fileinfo[9]) .' GMT';
  $etag = '"'. md5($last_modified) .'"';

  // See if the client has provided the required HTTP headers:
  $if_modified_since = isset($_SERVER['HTTP_IF_MODIFIED_SINCE'])
                        ? stripslashes($_SERVER['HTTP_IF_MODIFIED_SINCE'])
                        : FALSE;
  $if_none_match = isset($_SERVER['HTTP_IF_NONE_MATCH'])
                    ? stripslashes($_SERVER['HTTP_IF_NONE_MATCH'])
                    : FALSE;

  if ($if_modified_since && $if_none_match
      && $if_none_match == $etag // etag must match
      && $if_modified_since == $last_modified) { // if-modified-since must match
    header('HTTP/1.1 304 Not Modified');
    // All 304 responses must send an etag if the 200 response
    // for the same object contained an etag
    header('Etag: '. $etag);
    // We must also set Last-Modified again, so that we overwrite Drupal's
    // default Last-Modified header with the right one
    header('Last-Modified: '. $last_modified);
    exit;
  }

  // Send appropriate response:
  $headers[] = 'Last-Modified: '. $last_modified;
  $headers[] = 'ETag: '. $etag;
}

/**
 * build an image cache derivative
 *
 * @param $actions  Array of imagecache actions.
 * @param $src      Path of the source file.
 * @param $dst      Path of the destination file.
 * @param $tmp      Path of the temporary file used for manipulating the image.
 * @return TRUE - derivative generated, FALSE - no derivative generated, NULL - derivative being generated
 */
function imagecache_build_derivative($actions, $src, $dst) {
  // get the folder for the final location of this preset...
  $dir = dirname($dst);

  // Build the destination folder tree if it doesn't already exists.
  if (!file_check_directory($dir, FILE_CREATE_DIRECTORY) && !mkdir($dir, 0775, TRUE)) {
    watchdog('imagecache', 'Failed to create imagecache directory: %dir', array('%dir' => $dir), WATCHDOG_ERROR);
    return FALSE;
  }

  // Simply copy the file if there are no actions.
  if (empty($actions)) {
    return file_copy($src, $dst, FILE_EXISTS_REPLACE);
  }

  if (!$image = imageapi_image_open($src)) {
    return FALSE;
  }

  foreach ($actions as $action) {
    if (!empty($action['data'])) {
      // QuickSketch, why do these run first/twice? - dopry.
      if (isset($action['data']['width'])) {
        $width = _imagecache_filter('width', $action['data']['width'], $image->info['width'], $image->info['height']);
      }
      if (isset($action['data']['height'])) {
        $height = _imagecache_filter('height', $action['data']['height'], $image->info['width'], $image->info['height']);
      }
      foreach ($action['data'] as $key => $value) {
        $action['data'][$key] = _imagecache_filter($key, $value, $image->info['width'], $image->info['height'], $width, $height);
      }
    }
    if (!_imagecache_apply_action($action, $image)) {
      watchdog('imagecache', 'action(id:%id): %action failed for %src', array('%id' => $action['actionid'], '%action' => $action['action'], '%src' => $src), WATCHDOG_ERROR);
      return FALSE;
    }
  }

  if (!imageapi_image_close($image, $dst)) {
    if (file_exists($dst)) {
      watchdog('imagecache', 'Cached image file %dst already exists. There may be an issue with your rewrite configuration.', array('%dst' => $dst), WATCHDOG_ERROR);
    }
    return FALSE;
  }

  return TRUE;
}

/**
 * Implementation of hook_user().
 */
function imagecache_user($op, &$edit, &$account, $category = NULL) {
  // Flush cached old user picture.
  if ($op == 'update' && !empty($account->picture)) {
    imagecache_image_flush($account->picture);
  }
}

/**
 * Implementation of hook_imagefield_file().
 */
function imagecache_imagefield_file($op, $file) {
  switch ($op) {
    // Delete imagecache presets when imagecache images are deleted.
    case 'delete': imagecache_image_flush($file['filepath']); break;

    // Create imagecache derivatives when files are saved.
    case 'save':
      break;
  }

}

/**
 * Implementation of hook_field_formatter_info().
 *
 * imagecache formatters are named as $presetname_$style
 * $style is used to determine how the preset should be rendered.
 * If you are implementing custom imagecache formatters please treat _ as
 * reserved.
 *
 * @todo: move the linking functionality up to imagefield and clean up the default image
 * integration.
 */
function imagecache_field_formatter_info() {
  $formatters = array();
  foreach (imagecache_presets() as $preset) {
    $formatters[$preset['presetname'] .'_default'] = array(
      'label' => t('@preset image', array('@preset' => $preset['presetname'])),
      'field types' => array('image', 'filefield'),
    );
    $formatters[$preset['presetname'] .'_linked'] = array(
      'label' => t('@preset image linked to node', array('@preset' => $preset['presetname'])),
      'field types' => array('image', 'filefield'),
    );
    $formatters[$preset['presetname'] .'_imagelink'] = array(
      'label' => t('@preset image linked to image', array('@preset' => $preset['presetname'])),
      'field types' => array('image', 'filefield'),
    );
    $formatters[$preset['presetname'] .'_path'] = array(
      'label' => t('@preset file path', array('@preset' => $preset['presetname'])),
      'field types' => array('image', 'filefield'),
    );
    $formatters[$preset['presetname'] .'_url'] = array(
      'label' => t('@preset URL', array('@preset' => $preset['presetname'])),
      'field types' => array('image', 'filefield'),
    );
  }
  return $formatters;
}

function theme_imagecache_formatter($element) {
  if (isset($element['#item']['nid']) && $node = node_load($element['#item']['nid'])) {
    return imagecache_field_formatter($element['#field_name'], $element['#item'], $element['#formatter'], $node);
  }
}


/**
 * Implementation of hook_field_formatter().
 */
function imagecache_field_formatter($field, $item, $formatter, $node) {
  if (empty($item['fid']) && $field['use_default_image']) {
    $item = $field['default_image'];
  }
  // Views does not load the file for us, while CCK display fields does.
  if (empty($item['filepath'])) {
    $item = array_merge($item, field_file_load($item['fid']));
  }
  if (is_string($item['data'])) {
    $item['data'] = unserialize($item['data']);
  }
  $alt = empty($item['data']['alt']) ? '' : $item['data']['alt'];
  $title = empty($item['data']['title']) ? '' : $item['data']['title'];
  $parts =  explode('_', $formatter);
  $style = array_pop($parts);
  $presetname = implode('_', $parts);

  $class = "imagecache imagecache-$presetname imagecache-$style imagecache-$formatter";
  if ($preset = imagecache_preset_by_name($presetname)) {
    $item['filepath'] = $item['fid'] == 'upload' ? $item['preview'] : $item['filepath'];
    switch ($style) {
      case 'linked':
        $imagetag = theme('imagecache', $presetname, $item['filepath'], $alt, $title);
        return l($imagetag, 'node/'. $node->nid, array('attributes' => array('class' => $class), 'html' => TRUE));

      case 'imagelink':
        $original_image_url = file_create_url($item['filepath']);
        $imagetag =  theme('imagecache', $presetname, $item['filepath'], $alt, $title);
        return l($imagetag, $original_image_url, array('attributes' => array('class' => $class), 'html' => TRUE));

      case 'url':
        return imagecache_create_url($presetname, $item['filepath']);

      case 'path':
        return imagecache_create_path($presetname, $item['filepath']);

      default:
        return theme('imagecache', $presetname, $item['filepath'], $alt, $title, array('class' => $class));
    }
  }
  return '<!-- imagecache formatter preset('. $presetname .') not found! -->';
}

/**
 * Filter key word values such as 'top', 'right', 'center', and also percentages.
 * All returned values are in pixels relative to the passed in height and width.
 */
function _imagecache_filter($key, $value, $current_width, $current_height, $new_width = NULL, $new_height = NULL) {
  switch ($key) {
    case 'width':
      $value = _imagecache_percent_filter($value, $current_width);
      break;
    case 'height':
      $value = _imagecache_percent_filter($value, $current_height);
      break;
    case 'xoffset':
      $value = _imagecache_keyword_filter($value, $current_width, $new_width);
      break;
    case 'yoffset':
      $value = _imagecache_keyword_filter($value, $current_height, $new_height);
      break;
  }
  return $value;
}

/**
 * Accept a percentage and return it in pixels.
 */
function _imagecache_percent_filter($value, $current_pixels) {
  if (strpos($value, '%') !== FALSE) {
    $value = str_replace('%', '', $value) * 0.01 * $current_pixels;
  }
  return $value;
}

/**
 * Accept a keyword (center, top, left, etc) and return it as an offset in pixels.
 */
function _imagecache_keyword_filter($value, $current_pixels, $new_pixels) {
  switch ($value) {
    case 'top':
    case 'left':
      $value = 0;
      break;
    case 'bottom':
    case 'right':
      $value = $current_pixels - $new_pixels;
      break;
    case 'center':
      $value = $current_pixels/2 - $new_pixels/2;
      break;
  }
  return $value;
}

/**
 * Recursively delete all files and folders in the specified filepath, then
 * delete the containing folder.
 *
 * Note that this only deletes visible files with write permission.
 *
 * @param string $path
 *   A filepath relative to file_directory_path.
 */
function _imagecache_recursive_delete($path) {
  if (is_file($path) || is_link($path)) {
    unlink($path);
  }
  elseif (is_dir($path)) {
    $d = dir($path);
    while (($entry = $d->read()) !== FALSE) {
      if ($entry == '.' || $entry == '..') continue;
      $entry_path = $path .'/'. $entry;
      _imagecache_recursive_delete($entry_path);
    }
    $d->close();
    rmdir($path);
  }
  else {
    watchdog('imagecache', 'Unknown file type(%path) stat: %stat ',
              array('%path' => $path,  '%stat' => print_r(stat($path),1)), WATCHDOG_ERROR);
  }

}

/**
 * Create and image tag for an imagecache derivative
 *
 * @param $namespace
 *   presetname of the derivative you wish to generate a tag for.
 * @param $path
 *   path to the original image you wish to create a derivative image tag for.
 * @param $alt
 *   img tag alternate text
 * @param $title
 *   img tag title text
 * @param attributes
 *   optional drupal attributes array. If attributes is set, the default imagecache classes
 *   will not be set automatically, you must do this manually.
 */
function theme_imagecache($namespace, $path, $alt = '', $title = '', $attributes = NULL) {
  if ($image = image_get_info(imagecache_create_path($namespace, $path))) {
    $attributes['width'] = $image['width'];
    $attributes['height'] = $image['height'];
  }
  // check is_null so people can intentionally pass an empty array of attributes to override
  // the defaults completely... if
  if (is_null($attributes)) {
    $attributes['class'] = 'imagecache imagecache-'. $namespace;
  }
  $attributes = drupal_attributes($attributes);
  $imagecache_url = imagecache_create_url($namespace, $path);
  return '<img src="'. $imagecache_url .'" alt="'. check_plain($alt) .'" title="'. check_plain($title) .'" '. $attributes .' />';
}

function theme_imagecache_imagelink($namespace, $path, $alt = '', $title = '', $attributes = NULL) {
  $image = theme('imagecache', $namespace, $path, $alt, $title);
  $original_image_url = file_create_url($path);
  return l($image, $original_image_url, array('absolute' => FALSE, 'html' => TRUE));
}


/************************************************************************************
 * ImageCache action implementation example in module.
 */
function imagecache_resize_image(&$image, $data) {
  if (!imageapi_image_resize($image, $data['width'], $data['height'])) {
    watchdog('imagecache', 'imagecache_resize_image failed. image: %image, data: %data.', array('%path' => $image, '%data' => print_r($data, TRUE)), WATCHDOG_ERROR);
    return FALSE;
  }
  return TRUE;
}

function imagecache_resize_form($action) {
  $form['width'] = array(
    '#type' => 'textfield',
    '#title' => t('Width'),
    '#default_value' => isset($action['width']) ? $action['width'] : '100%',
    '#description' => t('Enter a width in pixels or as a percentage. i.e. 500 or 80%.'),
  );
  $form['height'] = array(
    '#type' => 'textfield',
    '#title' => t('Height'),
    '#default_value' => isset($action['height']) ? $action['height'] : '100%',
    '#description' => t('Enter a height in pixels or as a percentage. i.e. 500 or 80%.'),
  );
  return $form;
}

/**
 *  ImageCache 2.x API
 *
 *  The API for imagecache has changed.  The 2.x API returns more structured
 *  data, has shorter function names, and implements more aggressive metadata
 *  caching.
 *
 */

/**
 * Get an array of all presets and their settings.
 *
 * @param reset
 *   if set to TRUE it will clear the preset cache
 *
 * @return
 *   array of presets array( $preset_id => array('presetid' => integer, 'presetname' => string))
 */
function imagecache_presets($reset = FALSE) {
  static $presets = array();

  // Clear  caches if $reset is TRUE;
  if ($reset) {
    $presets = array();
    cache_clear_all('imagecache:presets', 'cache');

    // Clear the content.module cache (refreshes the list of formatters provided by imagefield.module).
    if (module_exists('content')) {
      content_clear_type_cache();
    }
  }
  // Return presets if the array is populated.
  if (!empty($presets)) {
    return $presets;
  }

  // Grab from cache or build the array. To ensure that the Drupal 5 upgrade
  // path works, we also check whether the presets list is an array.
  if (($cache = cache_get('imagecache:presets', 'cache')) && is_array($cache->data)) {
    $presets = $cache->data;
  }
  else {
    $normal_presets = array();

    $result = db_query('SELECT * FROM {imagecache_preset} ORDER BY presetname');
    while ($preset = db_fetch_array($result)) {
      $presets[$preset['presetid']] = $preset;
      $presets[$preset['presetid']]['actions'] = imagecache_preset_actions($preset);
      $presets[$preset['presetid']]['storage'] = IMAGECACHE_STORAGE_NORMAL;

      // Collect normal preset names so we can skip defaults and mark overrides accordingly
      $normal_presets[$preset['presetname']] = $preset['presetid'];
    }

    // Collect default presets and allow modules to modify them before they
    // are cached.
    $default_presets = module_invoke_all('imagecache_default_presets');
    drupal_alter('imagecache_default_presets', $default_presets);

    // Add in default presets if they don't conflict with any normal presets.
    // Mark normal presets that take the same preset namespace as overrides.
    foreach ($default_presets as $preset) {
      if (!empty($preset['presetname'])) {
        if (!isset($normal_presets[$preset['presetname']])) {
          $preset['storage'] = IMAGECACHE_STORAGE_DEFAULT;
          // Use a string preset identifier
          $preset['presetid'] = $preset['presetname'];
          $presets[$preset['presetname']] = $preset;
        }
        else {
          $presetid = $normal_presets[$preset['presetname']];
          $presets[$presetid]['storage'] = IMAGECACHE_STORAGE_OVERRIDE;
        }
      }
    }

    cache_set('imagecache:presets', $presets);
  }
  return $presets;
}

/**
 * Load a preset by preset_id.
 *
 * @param preset_id
 *   The numeric id of a preset.
 *
 * @return
 *   preset array( 'presetname' => string, 'presetid' => integet)
 *   empty array if preset_id is an invalid preset
 */
function imagecache_preset($preset_id, $reset = FALSE) {
  $presets = imagecache_presets($reset);
  return (isset($presets[$preset_id])) ? $presets[$preset_id] : array();
}

/**
 * Load a preset by name.
 *
 * @param preset_name
 *
 * @return
 *   preset array( 'presetname' => string, 'presetid' => integer)
 *   empty array if preset_name is an invalid preset
 */

function imagecache_preset_by_name($preset_name) {
  static $presets_by_name = array();
  if (!$presets_by_name &&  $presets = imagecache_presets()) {
    foreach ($presets as $preset) {
      $presets_by_name[$preset['presetname']] = $preset;
    }
  }
  return (isset($presets_by_name[$preset_name])) ? $presets_by_name[$preset_name] : array();
}

/**
 * Save an ImageCache preset.
 *
 * @param preset
 *   an imagecache preset array.
 * @return
 *   a preset array.  In the case of a new preset, 'presetid' will be populated.
 */
function imagecache_preset_save($preset) {
  // @todo: CRUD level validation?
  if (isset($preset['presetid']) && is_numeric($preset['presetid'])) {
    drupal_write_record('imagecache_preset', $preset, 'presetid');
  }
  else {
    drupal_write_record('imagecache_preset', $preset);
  }

  // Reset presets cache.
  imagecache_preset_flush($preset);
  imagecache_presets(TRUE);

  // Rebuild Theme Registry
  drupal_rebuild_theme_registry();

  return $preset;
}

function imagecache_preset_delete($preset) {
  imagecache_preset_flush($preset['presetid']);
  db_query('DELETE FROM {imagecache_action} where presetid = %d', $preset['presetid']);
  db_query('DELETE FROM {imagecache_preset} where presetid = %d', $preset['presetid']);
  imagecache_presets(TRUE);
  return TRUE;
}

function imagecache_preset_actions($preset, $reset = FALSE) {
  static $actions_cache = array();

  if ($reset || empty($actions_cache[$preset['presetid']])) {
    $result = db_query('SELECT * FROM {imagecache_action} where presetid = %d order by weight', $preset['presetid']);
    while ($row = db_fetch_array($result)) {
      $row['data'] = unserialize($row['data']);
      $actions_cache[$preset['presetid']][] = $row;
    }
  }

  return isset($actions_cache[$preset['presetid']]) ? $actions_cache[$preset['presetid']] : array();
}

/**
 * Flush cached media for a preset.
 * @param id
 *   A preset id.
 */
function imagecache_preset_flush($preset) {
  if (user_access('flush imagecache')) {
    $presetdir = realpath(file_directory_path() .'/imagecache/'. $preset['presetname']);
    if (is_dir($presetdir)) {
      _imagecache_recursive_delete($presetdir);
    }
  }
}

/**
 * Clear cached versions of a specific file in all presets.
 * @param $path
 *   The Drupal file path to the original image.
 */
function imagecache_image_flush($path) {
  foreach (imagecache_presets() as $preset) {
    file_delete(imagecache_create_path($preset['presetname'], $path));
  }
}

function imagecache_action($actionid) {
  static $actions;

  if (!isset($actions[$actionid])) {
    $action = array();

    $result = db_query('SELECT * FROM {imagecache_action} WHERE actionid=%d', $actionid);
    if ($row = db_fetch_array($result)) {
      $action = $row;
      $action['data'] = unserialize($action['data']);

      $definition = imagecache_action_definition($action['action']);
      $action = array_merge($definition, $action);
      $actions[$actionid] = $action;
    }
  }
  return $actions[$actionid];
}

function imagecache_action_load($actionid) {
  return imagecache_action($actionid, TRUE);
}

function imagecache_action_save($action) {
  $definition = imagecache_action_definition($action['action']);
  $action = array_merge($definition, $action);

  if (!empty($action['actionid'])) {
    drupal_write_record('imagecache_action', $action, 'actionid');
  }
  else {
    drupal_write_record('imagecache_action', $action);
  }
  $preset = imagecache_preset($action['presetid']);
  imagecache_preset_flush($preset);
  imagecache_presets(TRUE);
  return $action;
}

function imagecache_action_delete($action) {
  db_query('DELETE FROM {imagecache_action} WHERE actionid=%d', $action['actionid']);
  $preset = imagecache_preset($action['presetid']);
  imagecache_preset_flush($preset);
  imagecache_presets(TRUE);
}