<?php

/**

 * @file

 * GD2 toolkit for image manipulation within Drupal.

 */

/**

 * @addtogroup image

 * @{

 */

/**

 * Retrieve settings for the GD2 toolkit.

 */

function image_gd_settings() {

  if (image_gd_check_settings()) {

    $form['status'] = array(

      '#markup' => t('The GD toolkit is installed and working properly.')

    );

    $form['image_jpeg_quality'] = array(

      '#type' => 'textfield',

      '#title' => t('JPEG quality'),

      '#description' => t('Define the image quality for JPEG manipulations. Ranges from 0 to 100. Higher values mean better image quality but bigger files.'),

      '#size' => 10,

      '#maxlength' => 3,

      '#default_value' => variable_get('image_jpeg_quality', 75),

      '#field_suffix' => t('%'),

    );

    $form['#element_validate'] = array('image_gd_settings_validate');

    return $form;

  }

  else {

    form_set_error('image_toolkit', t('The GD image toolkit requires that the GD module for PHP be installed and configured properly. For more information see <a href="@url">PHP\'s image documentation</a>.', array('@url' => 'http://php.net/image')));

    return FALSE;

  }

}

/**

 * Validate the submitted GD settings.

 */

function image_gd_settings_validate($form, &$form_state) {

  // Validate image quality range.

  $value = $form_state['values']['image_jpeg_quality'];

  if (!is_numeric($value) || $value < 0 || $value > 100) {

    form_set_error('image_jpeg_quality', t('JPEG quality must be a number between 0 and 100.'));

  }

}

/**

 * Verify GD2 settings (that the right version is actually installed).

 *

 * @return

 *   A boolean indicating if the GD toolkit is available on this machine.

 */

function image_gd_check_settings() {

  // GD2 support is available.

  return function_exists('imagegd2');

}

/**

 * Scale an image to the specified size using GD.

 *

 * @param $image

 *   An image object. The $image->resource, $image->info['width'], and

 *   $image->info['height'] values will be modified by this call.

 * @param $width

 *   The new width of the resized image, in pixels.

 * @param $height

 *   The new height of the resized image, in pixels.

 * @return

 *   TRUE or FALSE, based on success.

 *

 * @see image_resize()

 */

function image_gd_resize(stdClass $image, $width, $height) {

  $res = image_gd_create_tmp($image, $width, $height);

  if (!imagecopyresampled($res, $image->resource, 0, 0, 0, 0, $width, $height, $image->info['width'], $image->info['height'])) {

    return FALSE;

  }

  imagedestroy($image->resource);

  // Update image object.

  $image->resource = $res;

  $image->info['width'] = $width;

  $image->info['height'] = $height;

  return TRUE;

}

/**

 * Rotate an image the given number of degrees.

 *

 * @param $image

 *   An image object. The $image->resource, $image->info['width'], and

 *   $image->info['height'] values will be modified by this call.

 * @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_rotate()

 */

function image_gd_rotate(stdClass $image, $degrees, $background = NULL) {

  // PHP installations using non-bundled GD do not have imagerotate.

  if (!function_exists('imagerotate')) {

    watchdog('image', 'The image %file could not be rotated because the imagerotate() function is not available in this PHP installation.', array('%file' => $image->source));

    return FALSE;

  }

  // PHP 5.5 GD bug: https://bugs.php.net/bug.php?id=65148: To prevent buggy

  // behavior on negative multiples of 90 degrees we convert any negative

  // angle to a positive one between 0 and 360 degrees.

  $degrees -= floor($degrees / 360) * 360;

  // Convert the hexadecimal background value to a RGBA array.

  if (isset($background)) {

    $background = array(

      'red' => $background >> 16 & 0xFF,

      'green' => $background >> 8 & 0xFF,

      'blue' => $background & 0xFF,

      'alpha' => 0,

    );

  }

  else {

    // Background color is not specified: use transparent white as background.

    $background = array(

      'red' => 255,

      'green' => 255,

      'blue' => 255,

      'alpha' => 127

    );

  }

  // Store the color index for the background as that is what GD uses.

  $background_idx = imagecolorallocatealpha($image->resource, $background['red'], $background['green'], $background['blue'], $background['alpha']);

  // Images are assigned a new color palette when rotating, removing any

  // transparency flags. For GIF images, keep a record of the transparent color.

  if ($image->info['extension'] == 'gif') {

    // GIF does not work with a transparency channel, but can define 1 color

    // in its palette to act as transparent.

    // Get the current transparent color, if any.

    $gif_transparent_id = imagecolortransparent($image->resource);

    if ($gif_transparent_id !== -1) {

      // The gif already has a transparent color set: remember it to set it on

      // the rotated image as well.

      $transparent_gif_color = imagecolorsforindex($image->resource, $gif_transparent_id);

      if ($background['alpha'] >= 127) {

        // We want a transparent background: use the color already set to act

        // as transparent, as background.

        $background_idx = $gif_transparent_id;

      }

    }

    else {

      // The gif does not currently have a transparent color set.

      if ($background['alpha'] >= 127) {

        // But as the background is transparent, it should get one.

        $transparent_gif_color = $background;

      }

    }

  }

  $image->resource = imagerotate($image->resource, 360 - $degrees, $background_idx);

  // GIFs need to reassign the transparent color after performing the rotate.

  if (isset($transparent_gif_color)) {

    $background = imagecolorexactalpha($image->resource, $transparent_gif_color['red'], $transparent_gif_color['green'], $transparent_gif_color['blue'], $transparent_gif_color['alpha']);

    imagecolortransparent($image->resource, $background);

  }

  $image->info['width'] = imagesx($image->resource);

  $image->info['height'] = imagesy($image->resource);

  return TRUE;

}

/**

 * Crop an image using the GD toolkit.

 *

 * @param $image

 *   An image object. The $image->resource, $image->info['width'], and

 *   $image->info['height'] values will be modified by this call.

 * @param $x

 *   The starting x offset at which to start the crop, in pixels.

 * @param $y

 *   The starting y offset at which to start the crop, in pixels.

 * @param $width

 *   The width of the cropped area, in pixels.

 * @param $height

 *   The height of the cropped area, in pixels.

 * @return

 *   TRUE or FALSE, based on success.

 *

 * @see image_crop()

 */

function image_gd_crop(stdClass $image, $x, $y, $width, $height) {

  $res = image_gd_create_tmp($image, $width, $height);

  if (!imagecopyresampled($res, $image->resource, 0, 0, $x, $y, $width, $height, $width, $height)) {

    return FALSE;

  }

  // Destroy the original image and return the modified image.

  imagedestroy($image->resource);

  $image->resource = $res;

  $image->info['width'] = $width;

  $image->info['height'] = $height;

  return TRUE;

}

/**

 * Convert an image resource to grayscale.

 *

 * Note that transparent GIFs loose transparency when desaturated.

 *

 * @param $image

 *   An image object. The $image->resource value will be modified by this call.

 * @return

 *   TRUE or FALSE, based on success.

 *

 * @see image_desaturate()

 */

function image_gd_desaturate(stdClass $image) {

  // PHP installations using non-bundled GD do not have imagefilter.

  if (!function_exists('imagefilter')) {

    watchdog('image', 'The image %file could not be desaturated because the imagefilter() function is not available in this PHP installation.', array('%file' => $image->source));

    return FALSE;

  }

  return imagefilter($image->resource, IMG_FILTER_GRAYSCALE);

}

/**

 * GD helper function to create an image resource from a file.

 *

 * @param $image

 *   An image object. The $image->resource value will populated by this call.

 * @return

 *   TRUE or FALSE, based on success.

 *

 * @see image_load()

 */

function image_gd_load(stdClass $image) {

  $extension = str_replace('jpg', 'jpeg', $image->info['extension']);

  $function = 'imagecreatefrom' . $extension;

  if (function_exists($function) && $image->resource = $function($image->source)) {

    if (imageistruecolor($image->resource)) {

      return TRUE;

    }

    else {

      // Convert indexed images to truecolor, copying the image to a new

      // truecolor resource, so that filters work correctly and don't result

      // in unnecessary dither.

      $resource = image_gd_create_tmp($image, $image->info['width'], $image->info['height']);

      if ($resource) {

        imagecopy($resource, $image->resource, 0, 0, 0, 0, imagesx($resource), imagesy($resource));

        imagedestroy($image->resource);

        $image->resource = $resource;

      }

    }

    return (bool) $image->resource;

  }

  return FALSE;

}

/**

 * GD helper to write an image resource to a destination file.

 *

 * @param $image

 *   An image object.

 * @param $destination

 *   A string file URI or path where the image should be saved.

 * @return

 *   TRUE or FALSE, based on success.

 *

 * @see image_save()

 */

function image_gd_save(stdClass $image, $destination) {

  $scheme = file_uri_scheme($destination);

  // Work around lack of stream wrapper support in imagejpeg() and imagepng().

  if ($scheme && file_stream_wrapper_valid_scheme($scheme)) {

    // If destination is not local, save image to temporary local file.

    $local_wrappers = file_get_stream_wrappers(STREAM_WRAPPERS_LOCAL);

    if (!isset($local_wrappers[$scheme])) {

      $permanent_destination = $destination;

      $destination = drupal_tempnam('temporary://', 'gd_');

    }

    // Convert stream wrapper URI to normal path.

    $destination = drupal_realpath($destination);

  }

  $extension = str_replace('jpg', 'jpeg', $image->info['extension']);

  $function = 'image' . $extension;

  if (!function_exists($function)) {

    return FALSE;

  }

  if ($extension == 'jpeg') {

    $success = $function($image->resource, $destination, variable_get('image_jpeg_quality', 75));

  }

  else {

    // Always save PNG images with full transparency.

    if ($extension == 'png') {

      imagealphablending($image->resource, FALSE);

      imagesavealpha($image->resource, TRUE);

    }

    $success = $function($image->resource, $destination);

  }

  // Move temporary local file to remote destination.

  if (isset($permanent_destination) && $success) {

    return (bool) file_unmanaged_move($destination, $permanent_destination, FILE_EXISTS_REPLACE);

  }

  return $success;

}

/**

 * Create a truecolor image preserving transparency from a provided image.

 *

 * @param $image

 *   An image object.

 * @param $width

 *   The new width of the new image, in pixels.

 * @param $height

 *   The new height of the new image, in pixels.

 * @return

 *   A GD image handle.

 */

function image_gd_create_tmp(stdClass $image, $width, $height) {

  $res = imagecreatetruecolor($width, $height);

  if ($image->info['extension'] == 'gif') {

    // Find out if a transparent color is set, will return -1 if no

    // transparent color has been defined in the image.

    $transparent = imagecolortransparent($image->resource);

    if ($transparent >= 0) {

      // Find out the number of colors in the image palette. It will be 0 for

      // truecolor images.

      $palette_size = imagecolorstotal($image->resource);

      if ($palette_size == 0 || $transparent < $palette_size) {

        // Set the transparent color in the new resource, either if it is a

        // truecolor image or if the transparent color is part of the palette.

        // Since the index of the transparency color is a property of the

        // image rather than of the palette, it is possible that an image

        // could be created with this index set outside the palette size (see

        // http://stackoverflow.com/a/3898007).

        $transparent_color = imagecolorsforindex($image->resource, $transparent);

        $transparent = imagecolorallocate($res, $transparent_color['red'], $transparent_color['green'], $transparent_color['blue']);

        // Flood with our new transparent color.

        imagefill($res, 0, 0, $transparent);

        imagecolortransparent($res, $transparent);

      }

      else {

        imagefill($res, 0, 0, imagecolorallocate($res, 255, 255, 255));

      }

    }

  }

  elseif ($image->info['extension'] == 'png') {

    imagealphablending($res, FALSE);

    $transparency = imagecolorallocatealpha($res, 0, 0, 0, 127);

    imagefill($res, 0, 0, $transparency);

    imagealphablending($res, TRUE);

    imagesavealpha($res, TRUE);

  }

  else {

    imagefill($res, 0, 0, imagecolorallocate($res, 255, 255, 255));

  }

  return $res;

}

/**

 * Get details about an image.

 *

 * @param $image

 *   An image object.

 * @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').

 *

 * @see image_get_info()

 */

function image_gd_get_info(stdClass $image) {

  $details = FALSE;

  $data = @getimagesize($image->source);

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

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

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

    $details = array(

      'width'     => $data[0],

      'height'    => $data[1],

      'extension' => $extension,

      'mime_type' => $data['mime'],

    );

  }

  return $details;

}

/**

 * @} End of "addtogroup image".

 */