<?php
// $Id: imageapi.module,v 1.21 2008-07-14 20:40:49 drewish Exp $

/**
 * @file
 *
 * An ImageAPI supporting additional image plugins as modules.
 * Images are treated as objects, and images are not written per
 * manipulation as Drupal's core image handling works.
 *
 *
 * imageapi image api workflow...
 * $image = imageapi_image_open($path) to get an image object for $path...
 * image_X($image, $arg1, $arg2)  to manipulate image object...
 * imageapi_image_close($image) to overwrite original image.
 *
 */

/**
 * Implementation of hook_perm().
 */
function imageapi_perm() {
  return array('administer imageapi');
}

/**
 * Implementation of hook_menu().
 */
function imageapi_menu() {
  $items = array();
  $items['admin/settings/imageapi'] = array(
    'title' => 'ImageAPI',
    'description' => 'Configure ImageAPI.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('imageapi_settings'),
    'access arguments' => array('administer imageapi'),
  );

  $toolkits = imageapi_get_available_toolkits();
  if ($toolkits) {
    $items['admin/settings/imageapi/list'] = array(
      'title' => 'List',
      'type' => MENU_DEFAULT_LOCAL_TASK,
      'weight' => -1,
    );
    $items['admin/settings/imageapi/config'] = array(
      'title' => 'Configure',
      'type' => MENU_LOCAL_TASK,
      'page callback' => 'drupal_get_form',
      'page arguments' => array(imageapi_default_toolkit() .'_settings_form'),
      'access arguments' => array('administer imageapi'),
    );
    foreach ($toolkits as $module => $info) {
      if (function_exists($module .'_settings_form')) {
        $items['admin/settings/imageapi/config/'. $module] = array(
          'title' => $info['name'],
          'page callback' => 'drupal_get_form',
          'page arguments' => array($module .'_settings_form'),
          'access arguments' => array('administer imageapi'),
          'type' => $module == imageapi_default_toolkit() ? MENU_DEFAULT_LOCAL_TASK : MENU_LOCAL_TASK,
        );
      }
      else {
        drupal_set_message(t('ImageAPI toolkit missing settings form'), 'error');
      }
    }
  }
  return $items;
}

function imageapi_settings() {
  $form = array();

  $toolkits = imageapi_get_available_toolkits();

  switch (count($toolkits)) {
    case 0:
      $form['imageapi_toolkits']['#value'] = t('There are no image toolkit modules enabled. Toolkit modules can be enabled from the <a href="!admin-build-modules">module configuration page</a>.', array('!admin-build-modules' => url('admin/build/modules')));
      return $form;

    case 1:
      $toolkit = key($toolkits);
      // The variable needs to be manually set. Otherwise, if a user has two
      // toolkits and disables the selected one they won't be able to select the
      // remaing toolkit.
      variable_set('imageapi_image_toolkit', $toolkit);
      $form['imageapi_image_toolkit']['#value'] = t('The %toolkit module is the only enabled image toolkit. Drupal will use it for resizing, cropping and other image manipulations.', array('%toolkit' => $toolkits[$toolkit]['name']));
      return $form;

    default:
      $options = array();
      foreach ($toolkits as $module => $info) {
        $options[$module] = $info['name'];
      }
      $form['imageapi_image_toolkit'] = array(
        '#type' => 'radios',
        '#title' => t('Select a default image processing toolkit'),
        '#default_value' => imageapi_default_toolkit(),
        '#options' => $options,
        '#description' => t('This setting lets you choose which toolkit Drupal uses resizing, cropping and other image manipulations.'),
      );
  }

  return system_settings_form($form);
}

/**
 * Return a list of available toolkits.
 *
 * @return
 *   An array of the enabled image toolkit modules. The module name is the key
 *   and the value is a sub-array with the module's 'name' and 'description'.
 */
function imageapi_get_available_toolkits() {
  static $toolkits;

  if (!isset($toolkits)) {
    $toolkits = array();
    foreach (module_implements('imageapi_toolkit', true) as $module) {
      $info = drupal_parse_info_file(drupal_get_path('module', $module) .'/'. $module .'.info');
      $toolkits[$module] = array('name' => $info['name'], 'description' => $info['description']);
    }
  }

  return $toolkits;
}

/**
 * Retrieve the name of the currently used toolkit.
 *
 * @return
 *   String containing the name of the toolkit, or false if none is available.
 */
function imageapi_default_toolkit() {
  $toolkit = variable_get('imageapi_image_toolkit', 'imageapi_gd');
  // Verify that the image toolkit is available.
  if (isset($toolkit) && module_exists($toolkit)) {
    return $toolkit;
  }
  // If it's not fall back to first available toolist.
  foreach (imageapi_get_available_toolkits() as $toolkit => $info) {
    return $toolkit;
  }
  return false;
}

/**
 * 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 $image
 *   An ImageAPI Image object.
 * @param $width
 *   The target width in pixels.
 * @param $height
 *   The target height in pixels.
 * @return
 *   True or false, based on success.
 */
function imageapi_image_scale_and_crop(&$image, $width, $height) {
  $aspect = $image->info['height'] / $image->info['width'];
  if (empty($height)) $height = $width / $aspect;
  if (empty($width)) $width = $height * $aspect;

  $scale = max($width / $image->info['width'], $height / $image->info['height']);
  $x = (int) round(($image->info['width'] * $scale - $width) / 2);
  $y = (int) round(($image->info['height'] * $scale - $height) / 2);

  if (imageapi_image_resize($image, $image->info['width'] * $scale, $image->info['height'] * $scale)) {
    return imageapi_image_crop($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 ImageAPI Image object.
 * @param $width
 *   The target width in pixels.
 * @param $height
 *   The target height in pixels.
 * @param $upscale
 *   Allow upscaling.
 * @return
 *   True or false, based on success.
 */
function imageapi_image_scale(&$image, $width, $height, $upscale = false) {
  // set width/height according to aspect ratio if either is empty;
  $aspect = $image->info['height'] / $image->info['width'];
  if (empty($height)) $height = $width / $aspect;
  if (empty($width)) $width = $height * $aspect;
  
  // Don't scale up.
  if (!$upscale && round($width) >= $image->info['width'] && round($height) >= $image->info['height']) {
    return true;
  }

  $aspect = $image->info['height'] / $image->info['width'];
  if ($aspect < $height / $width) {
    $height = $width * $aspect;
  }
  else {
    $width = $height / $aspect;
  }

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

  return call_user_func($image->toolkit .'_image_resize', $image, $width, $height);
}

/**
 * Resize an image to the given dimensions (ignoring aspect ratio).
 *
 * @param $source        The filepath of the source image.
 * @param $source
 *   The filepath 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.
 * @param $toolkit
 *   An optional override of the default image toolkit.
 * @return
 *   True or false, based on success.
 */
function imageapi_image_resize(&$image, $width, $height) {
  $width = (int) round($width);
  $height = (int) round($height);
  
  return call_user_func($image->toolkit .'_image_resize', $image, $width, $height);
}

/**
 * Rotate an image by the given number of degrees.
 *
 * @param $image
 *   An imageapi image object returned by imageapi_image_open().
 * @param $degrees
 *   The number of (clockwise) degrees to rotate the image.
 * @param $bg_color
 *   An hexidecimal integer specifying the background color to use for the
 *   uncovered area of the image after the rotation. E.g. 0x000000 for black,
 *   0xff00ff for magenta, and 0xffffff for white.
 * @return
 *   True or false, based on success.
 */
function imageapi_image_rotate(&$image, $degrees, $bgcolor = 0x000000) {
  return call_user_func($image->toolkit .'_image_rotate', $image, $degrees, $bgcolor);
}

/**
 * Sharpen an image given some sharpening parameters.
 *
 * NOTE: These parameters only have an effect when Imagemagick is used.
 *       GD will used a fixed convolution matrix as described in imageapi_gd.module
 *
 * @param $image
 *   An imageapi image object returned by imageapi_image_open().
 * @param $radius
 *   The radius of the gaussian, in pixels, not counting the center pixel. (default 0.5)
 * @param $sigma
 *   The standard deviation of the gaussian, in pixels. (default 0.5)
 * @param $amount
 *   The percentage of the difference between the original and the blur image that is
 *   added back into the original. (default 100)
 * @param $threshold
 *   The threshold, as a fraction of max RGB levels, needed to apply the difference
 *   amount. (default 0.05)
 * @return
 *   True or false, based on success.
 */
function imageapi_image_sharpen(&$image, $radius, $sigma, $amount, $threshold) {
  return call_user_func($image->toolkit .'_image_sharpen', $image, $radius, $sigma, $amount, $threshold);
}

/**
 * Crop an image to the rectangle specified by the given rectangle.
 *
 * @param $image
 *   An imageapi image object returned by imageapi_image_open().
 * @param $x
 *   The top left co-ordinate of the crop area (x axis value).
 * @param $y
 *   The top left co-ordinate of the crop area (y axis value).
 * @param $width
 *   The target width in pixels.
 * @param $height
 *   The target height in pixels.
 * @return
 *   True or false, based on success.
 */
function imageapi_image_crop(&$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 call_user_func($image->toolkit .'_image_crop', $image, $x, $y, $width, $height);
}

/**
 * Convert an image to grayscale.
 *
 * @param $image
 *   An imageapi image object returned by imageapi_image_open().
 * @return
 *   True or false, based on success.
 */
function imageapi_image_desaturate(&$image) {
  return call_user_func($image->toolkit .'_image_desaturate', $image);
}

/**
 * Open an image file and return an imageapi image object. Any changes to the
 * file are not saved until imageapi_image_close() is called.
 *
 * @param $file
 *   Path to an image file.
 * @param $toolkit
 *   An optional, image toolkit name to override the default.
 * @return
 *   ImageAPI Image object or FALSE if there was a problem opening the file.
 */
function imageapi_image_open($file, $toolkit = false) {
  if (!$toolkit) {
    $toolkit = imageapi_default_toolkit();
  }
  if ($toolkit) {
    $image = new stdClass();
    $image->source = $file;
    $image->info = image_get_info($file);
    $image->toolkit = $toolkit;
    if ($image = call_user_func($image->toolkit .'_image_open', $image)) {
      return $image;
    }
  }
  watchdog('imageapi', 'ImageAPI failed to open %file with %toolkit', array('%file' => $file, '%toolkit' => $toolkit), WATCHDOG_WARNING);
  return false;
}

/**
 * Close the image and save the changes to a file.
 *
 * @param $image
 *   imageAPI image object.
 *
 * @param $destination
 *   Destination path where the image should be saved. If it is empty the
 *   original image file will be overwritten.
 */
function imageapi_image_close($image, $destination = '') {
  if (empty($destination)) {
    $destination = $image->source;
  }
  if ($return = call_user_func($image->toolkit .'_image_close', $image, $destination)) {
    if (@chmod($destination, 0775)) {
      return $return;
    }
    watchdog('imageapi', 'Could not set permissons on destination file: %file', array('%file' => $destination));
  }
  return false;
}


/**
 * Convert a hex string to its RGBA (Red, Green, Blue, Alpha) integer
 * components.
 *
 * @param $hex
 *   A string specifing an RGB color in the formats:
 *   '#ABC','ABC','#ABCD','ABCD','#AABBCC','AABBCC','#AABBCCDD','AABBCCDD'
 * @return
 *   An array with four elements for red, green, blue, and alpha.
 */
function imageapi_hex2rgba($hex) {
  $hex = ltrim($hex, '#');
  if (preg_match('/^[0-9a-f]{3}$/i', $hex)) {
    // 'FA3' is the same as 'FFAA33' so r=FF, g=AA, b=33
    $r = str_repeat($hex{0}, 2);
    $g = str_repeat($hex{1}, 2);
    $b = str_repeat($hex{2}, 2);
    $a = '0';
  }
  elseif (preg_match('/^[0-9a-f]{6}$/i', $hex)) {
    // #FFAA33 or r=FF, g=AA, b=33
    list($r, $g, $b) = str_split($hex, 2);
    $a = '0';
  }
  elseif (preg_match('/^[0-9a-f]{8}$/i', $hex)) {
    // #FFAA33 or r=FF, g=AA, b=33
    list($r, $g, $b, $a) = str_split($hex, 2);
  }
  elseif (preg_match('/^[0-9a-f]{4}$/i', $hex)) {
    // 'FA37' is the same as 'FFAA3377' so r=FF, g=AA, b=33, a=77
    $r = str_repeat($hex{0}, 2);
    $g = str_repeat($hex{1}, 2);
    $b = str_repeat($hex{2}, 2);
    $a = str_repeat($hex{3}, 2);
  }
  else {
    //error: invalide hex string, TODO: set form error..
    return false;
  }

  $r = hexdec($r);
  $g = hexdec($g);
  $b = hexdec($b);
  $a = hexdec($a);
  return array($r, $g, $b, $a);
}