<?php

// $Id: image.inc,v 1.24 2008/01/28 16:05:17 goba Exp $

/**

 * @file

 * API for manipulating images.

 */

/**

 * @defgroup image Image toolkits

 * @{

 * 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 ImageMagic 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 installed by copying the image.ToolkitName.inc file into

 * Drupal's includes directory. The toolkit must then be enabled using the

 * admin/settings/image-toolkit form.

 *

 * Only one toolkit maybe 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 of toolkit name => descriptive title.

 */

function image_get_available_toolkits() {

  $toolkits = file_scan_directory('includes', 'image\..*\.inc$');

  $output = array();

  foreach ($toolkits as $file => $toolkit) {

    include_once "./$file";

    $function = str_replace('.', '_', $toolkit->name) .'_info';

    if (function_exists($function)) {

      $info = $function();

      $output[$info['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 (!$toolkit) {

    $toolkit = variable_get('image_toolkit', 'gd');

    $toolkit_file = './includes/image.'. $toolkit .'.inc';

    if (isset($toolkit) && file_exists($toolkit_file)) {

      include_once $toolkit_file;

    }

    elseif (!image_gd_check_settings()) {

      $toolkit = FALSE;

    }

  }

  return $toolkit;

}

/**

 * Invokes the given method using the currently selected toolkit.

 *

 * @param $method

 *   A string containing the method to invoke.

 * @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, $params = array()) {

  if ($toolkit = image_get_toolkit()) {

    $function = 'image_'. $toolkit .'_'. $method;

    if (function_exists($function)) {

      return call_user_func_array($function, $params);

    }

    else {

      watchdog('php', 'The selected image handling toolkit %toolkit can not correctly process %function.', array('%toolkit' => $toolkit, '%function' => $function), WATCHDOG_ERROR);

      return FALSE;

    }

  }

}

/**

 * Get details about an image.

 *

 * Drupal only supports GIF, JPG and PNG file formats.

 *

 * @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($file) {

  if (!is_file($file)) {

    return FALSE;

  }

  $details = FALSE;

  $data = @getimagesize($file);

  $file_size = @filesize($file);

  if (isset($data) && is_array($data)) {

    $extensions = array('1' => 'gif', '2' => 'jpg', '3' => 'png');

    $extension = array_key_exists($data[2], $extensions) ?  $extensions[$data[2]] : '';

    $details = array('width'     => $data[0],

                     'height'    => $data[1],

                     'extension' => $extension,

                     'file_size' => $file_size,

                     'mime_type' => $data['mime']);

  }

  return $details;

}

/**

 * Scales an image to the exact width and height given. Achieves the

 * target aspect ratio by cropping the original image equally on both

 * sides, or equally on the top and bottom.  This function is, for

 * example, useful to create uniform sized avatars from larger images.

 *

 * The resulting image always has the exact target dimensions.

 *

 * @param $source

 *   The file path of the source image.

 * @param $destination

 *   The file path of the destination image.

 * @param $width

 *   The target width, in pixels.

 * @param $height

 *   The target height, in pixels.

 * @return

 *   TRUE or FALSE, based on success.

 */

function image_scale_and_crop($source, $destination, $width, $height) {

  $info = image_get_info($source);

  $scale = max($width / $info['width'], $height / $info['height']);

  $x = round(($info['width'] * $scale - $width) / 2);

  $y = round(($info['height'] * $scale - $height) / 2);

  if (image_toolkit_invoke('resize', array($source, $destination, $info['width'] * $scale, $info['height'] * $scale))) {

    return image_toolkit_invoke('crop', array($destination, $destination, $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 $source

 *   The file path of the source image.

 * @param $destination

 *   The file path of the destination image.

 * @param $width

 *   The target width, in pixels.

 * @param $height

 *   The target height, in pixels.

 * @return

 *   TRUE or FALSE, based on success.

 */

function image_scale($source, $destination, $width, $height) {

  $info = image_get_info($source);

  // Don't scale up.

  if ($width >= $info['width'] && $height >= $info['height']) {

    return FALSE;

  }

  $aspect = $info['height'] / $info['width'];

  if ($aspect < $height / $width) {

    $width = (int)min($width, $info['width']);

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

  }

  else {

    $height = (int)min($height, $info['height']);

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

  }

  return image_toolkit_invoke('resize', array($source, $destination, $width, $height));

}

/**

 * Resize an image to the given dimensions (ignoring aspect ratio).

 *

 * @param $source

 *   The file path of the source image.

 * @param $destination

 *   The file path of the destination image.

 * @param $width

 *   The target width, in pixels.

 * @param $height

 *   The target height, in pixels.

  * @return

 *   TRUE or FALSE, based on success.

 */

function image_resize($source, $destination, $width, $height) {

  return image_toolkit_invoke('resize', array($source, $destination, $width, $height));

}

/**

 * Rotate an image by the given number of degrees.

 *

 * @param $source

 *   The file path of the source image.

 * @param $destination

 *   The file path of the destination image.

 * @param $degrees

 *   The number of (clockwise) degrees to rotate the image.

 * @param $background

 *   An hexidecimal 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.

 * @return

 *   TRUE or FALSE, based on success.

 */

function image_rotate($source, $destination, $degrees, $background = 0x000000) {

  return image_toolkit_invoke('rotate', array($source, $destination, $degrees, $background));

}

/**

 * Crop an image to the rectangle specified by the given rectangle.

 *

 * @param $source

 *   The file path of the source image.

 * @param $destination

 *   The file path of the destination image.

 * @param $x

 *   The top left co-ordinate, in pixels, of the crop area (x axis value).

 * @param $y

 *   The top left co-ordinate, 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.

 */

function image_crop($source, $destination, $x, $y, $width, $height) {

  return image_toolkit_invoke('crop', array($source, $destination, $x, $y, $width, $height));

}

/**

 * @} End of "defgroup image".

 */