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Drupal example source code file (image.inc)

This example Drupal source code file (image.inc) is included in the DevDaily.com "Drupal Source Code Warehouse" project. The intent of this project is to help you "Learn Drupal by Example".

PHP - Drupal tags/keywords

array, aspect, directory, empty, false, file, function, height, if, image, php, return, toolkit, width

The image.inc Drupal example source code

<?php
// $Id: image.inc,v 1.42 2011/01/02 17:26:39 webchick Exp $

/**
 * @file
 * API for manipulating images.
 */

/**
 * @defgroup image Image toolkits
 * @{
 * Functions for image file manipulations.
 *
 * Drupal's image toolkits provide an abstraction layer for common image file
 * manipulations like scaling, cropping, and rotating. The abstraction frees
 * module authors from the need to support multiple image libraries, and it
 * allows site administrators to choose the library that's best for them.
 *
 * PHP includes the GD library by default so a GD toolkit is installed with
 * Drupal. Other toolkits like ImageMagick are available from contrib modules.
 * GD works well for small images, but using it with larger files may cause PHP
 * to run out of memory. In contrast the ImageMagick library does not suffer
 * from this problem, but it requires the ISP to have installed additional
 * software.
 *
 * Image toolkits are discovered based on the associated module's
 * hook_image_toolkits. Additionally the image toolkit include file
 * must be identified in the files array in the module.info file. The
 * toolkit must then be enabled using the admin/config/media/image-toolkit
 * form.
 *
 * Only one toolkit may be selected at a time. If a module author wishes to call
 * a specific toolkit they can check that it is installed by calling
 * image_get_available_toolkits(), and then calling its functions directly.
 */

/**
 * Return a list of available toolkits.
 *
 * @return
 *   An array with the toolkit names as keys and the descriptions as values.
 */
function image_get_available_toolkits() {
  // hook_image_toolkits returns an array of toolkit names.
  $toolkits = module_invoke_all('image_toolkits');

  $output = array();
  foreach ($toolkits as $name => $info) {
    // Only allow modules that aren't marked as unavailable.
    if ($info['available']) {
      $output[$name] = $info['title'];
    }
  }

  return $output;
}

/**
 * Retrieve the name of the currently used toolkit.
 *
 * @return
 *   String containing the name of the selected toolkit, or FALSE on error.
 */
function image_get_toolkit() {
  static $toolkit;

  if (!isset($toolkit)) {
    $toolkits = image_get_available_toolkits();
    $toolkit = variable_get('image_toolkit', 'gd');
    if (!isset($toolkits[$toolkit]) || !function_exists('image_' . $toolkit . '_load')) {
      // The selected toolkit isn't available so return the first one found. If
      // none are available this will return FALSE.
      reset($toolkits);
      $toolkit = key($toolkits);
    }
  }

  return $toolkit;
}

/**
 * Invokes the given method using the currently selected toolkit.
 *
 * @param $method
 *   A string containing the method to invoke.
 * @param $image
 *   An image object returned by image_load().
 * @param $params
 *   An optional array of parameters to pass to the toolkit method.
 *
 * @return
 *   Mixed values (typically Boolean indicating successful operation).
 */
function image_toolkit_invoke($method, stdClass $image, array $params = array()) {
  $function = 'image_' . $image->toolkit . '_' . $method;
  if (function_exists($function)) {
    array_unshift($params, $image);
    return call_user_func_array($function, $params);
  }
  watchdog('image', 'The selected image handling toolkit %toolkit can not correctly process %function.', array('%toolkit' => $image->toolkit, '%function' => $function), WATCHDOG_ERROR);
  return FALSE;
}

/**
 * Get details about an image.
 *
 * Drupal supports GIF, JPG and PNG file formats when used with the GD
 * toolkit, and may support others, depending on which toolkits are
 * installed.
 *
 * @param $filepath
 *   String specifying the path of the image file.
 * @param $toolkit
 *   An optional image toolkit name to override the default.
 *
 * @return
 *   FALSE, if the file could not be found or is not an image. Otherwise, a
 *   keyed array containing information about the image:
 *   - "width": Width, in pixels.
 *   - "height": Height, in pixels.
 *   - "extension": Commonly used file extension for the image.
 *   - "mime_type": MIME type ('image/jpeg', 'image/gif', 'image/png').
 *   - "file_size": File size in bytes.
 */
function image_get_info($filepath, $toolkit = FALSE) {
  $details = FALSE;
  if (!is_file($filepath) && !is_uploaded_file($filepath)) {
    return $details;
  }

  if (!$toolkit) {
    $toolkit = image_get_toolkit();
  }
  if ($toolkit) {
    $image = new stdClass();
    $image->source = $filepath;
    $image->toolkit = $toolkit;
    $details = image_toolkit_invoke('get_info', $image);
    if (isset($details) && is_array($details)) {
      $details['file_size'] = filesize($filepath);
    }
  }

  return $details;
}

/**
 * Scales an image to the exact width and height given.
 *
 * This function achieves the target aspect ratio by cropping the original image
 * equally on both sides, or equally on the top and bottom. This function is
 * useful to create uniform sized avatars from larger images.
 *
 * The resulting image always has the exact target dimensions.
 *
 * @param $image
 *   An image object returned by image_load().
 * @param $width
 *   The target width, in pixels.
 * @param $height
 *   The target height, in pixels.
 *
 * @return
 *   TRUE or FALSE, based on success.
 *
 * @see image_load()
 * @see image_resize()
 * @see image_crop()
 */
function image_scale_and_crop(stdClass $image, $width, $height) {
  $scale = max($width / $image->info['width'], $height / $image->info['height']);
  $x = ($image->info['width'] * $scale - $width) / 2;
  $y = ($image->info['height'] * $scale - $height) / 2;

  if (image_resize($image, $image->info['width'] * $scale, $image->info['height'] * $scale)) {
    return image_crop($image, $x, $y, $width, $height);
  }
  return FALSE;
}

/**
 * Scales an image to the given width and height while maintaining aspect ratio.
 *
 * The resulting image can be smaller for one or both target dimensions.
 *
 * @param $image
 *   An image object returned by image_load().
 * @param $width
 *   The target width, in pixels. This value is omitted then the scaling will
 *   based only on the height value.
 * @param $height
 *   The target height, in pixels. This value is omitted then the scaling will
 *   based only on the width value.
 * @param $upscale
 *   Boolean indicating that files smaller than the dimensions will be scaled
 *   up. This generally results in a low quality image.
 *
 * @return
 *   TRUE or FALSE, based on success.
 *
 * @see image_load()
 * @see image_scale_and_crop()
 */
function image_scale(stdClass $image, $width = NULL, $height = NULL, $upscale = FALSE) {
  $aspect = $image->info['height'] / $image->info['width'];

  if ($upscale) {
    // Set width/height according to aspect ratio if either is empty.
    $width = !empty($width) ? $width : $height / $aspect;
    $height = !empty($height) ? $height : $width / $aspect;
  }
  else {
    // Set impossibly large values if the width and height aren't set.
    $width = !empty($width) ? $width : 9999999;
    $height = !empty($height) ? $height : 9999999;

    // Don't scale up.
    if (round($width) >= $image->info['width'] && round($height) >= $image->info['height']) {
      return TRUE;
    }
  }

  if ($aspect < $height / $width) {
    $height = $width * $aspect;
  }
  else {
    $width = $height / $aspect;
  }

  return image_resize($image, $width, $height);
}

/**
 * Resize an image to the given dimensions (ignoring aspect ratio).
 *
 * @param $image
 *   An image object returned by image_load().
 * @param $width
 *   The target width, in pixels.
 * @param $height
 *   The target height, in pixels.
 *
 * @return
 *   TRUE or FALSE, based on success.
 *
 * @see image_load()
 * @see image_gd_resize()
 */
function image_resize(stdClass $image, $width, $height) {
  $width = (int) round($width);
  $height = (int) round($height);

  return image_toolkit_invoke('resize', $image, array($width, $height));
}

/**
 * Rotate an image by the given number of degrees.
 *
 * @param $image
 *   An image object returned by image_load().
 * @param $degrees
 *   The number of (clockwise) degrees to rotate the image.
 * @param $background
 *   An hexadecimal integer specifying the background color to use for the
 *   uncovered area of the image after the rotation. E.g. 0x000000 for black,
 *   0xff00ff for magenta, and 0xffffff for white. For images that support
 *   transparency, this will default to transparent. Otherwise it will
 *   be white.
 *
 * @return
 *   TRUE or FALSE, based on success.
 *
 * @see image_load()
 * @see image_gd_rotate()
 */
function image_rotate(stdClass $image, $degrees, $background = NULL) {
  return image_toolkit_invoke('rotate', $image, array($degrees, $background));
}

/**
 * Crop an image to the rectangle specified by the given rectangle.
 *
 * @param $image
 *   An image object returned by image_load().
 * @param $x
 *   The top left coordinate, in pixels, of the crop area (x axis value).
 * @param $y
 *   The top left coordinate, in pixels, of the crop area (y axis value).
 * @param $width
 *   The target width, in pixels.
 * @param $height
 *   The target height, in pixels.
 *
 * @return
 *   TRUE or FALSE, based on success.
 *
 * @see image_load()
 * @see image_scale_and_crop()
 * @see image_gd_crop()
 */
function image_crop(stdClass $image, $x, $y, $width, $height) {
  $aspect = $image->info['height'] / $image->info['width'];
  if (empty($height)) $height = $width / $aspect;
  if (empty($width)) $width = $height * $aspect;

  $width = (int) round($width);
  $height = (int) round($height);

  return image_toolkit_invoke('crop', $image, array($x, $y, $width, $height));
}

/**
 * Convert an image to grayscale.
 *
 * @param $image
 *   An image object returned by image_load().
 *
 * @return
 *   TRUE or FALSE, based on success.
 *
 * @see image_load()
 * @see image_gd_desaturate()
 */
function image_desaturate(stdClass $image) {
  return image_toolkit_invoke('desaturate', $image);
}


/**
 * Load an image file and return an image object.
 *
 * Any changes to the file are not saved until image_save() is called.
 *
 * @param $file
 *   Path to an image file.
 * @param $toolkit
 *   An optional, image toolkit name to override the default.
 *
 * @return
 *   An image object or FALSE if there was a problem loading the file. The
 *   image object has the following properties:
 *    - 'source' - The original file path.
 *    - 'info' - The array of information returned by image_get_info()
 *    - 'toolkit' - The name of the image toolkit requested when the image was
 *      loaded.
 *   Image toolkits may add additional properties. The caller is advised not to
 *   monkey about with them.
 *
 * @see image_save()
 * @see image_get_info()
 * @see image_get_available_toolkits()
 * @see image_gd_load()
 */
function image_load($file, $toolkit = FALSE) {
  if (!$toolkit) {
    $toolkit = image_get_toolkit();
  }
  if ($toolkit) {
    $image = new stdClass();
    $image->source = $file;
    $image->info = image_get_info($file, $toolkit);
    if (isset($image->info) && is_array($image->info)) {
      $image->toolkit = $toolkit;
      if (image_toolkit_invoke('load', $image)) {
        return $image;
      }
    }
  }
  return FALSE;
}

/**
 * Close the image and save the changes to a file.
 *
 * @param $image
 *   An image object returned by image_load(). The object's 'info' property
 *   will be updated if the file is saved successfully.
 * @param $destination
 *   Destination path where the image should be saved. If it is empty the
 *   original image file will be overwritten.
 *
 * @return
 *   TRUE or FALSE, based on success.
 *
 * @see image_load()
 * @see image_gd_save()
 */
function image_save(stdClass $image, $destination = NULL) {
  if (empty($destination)) {
    $destination = $image->source;
  }
  if ($return = image_toolkit_invoke('save', $image, array($destination))) {
    // Clear the cached file size and refresh the image information.
    clearstatcache();
    $image->info = image_get_info($destination, $image->toolkit);

    if (drupal_chmod($destination)) {
      return $return;
    }
  }
  return FALSE;
}

/**
 * @} End of "defgroup image".
 */

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