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Drupal example source code file (image.gd.inc)

This example Drupal source code file (image.gd.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, background, destination, false, function, gif, height, image, jpg, php, png, res, return, width

The image.gd.inc Drupal example source code

<?php
// $Id: image.gd.inc,v 1.18 2010/10/28 02:27:09 dries Exp $

/**
 * @file
 * GD2 toolkit for image manipulation within Drupal.
 */

/**
 * @ingroup 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() {
  if ($check = get_extension_funcs('gd')) {
    if (in_array('imagegd2', $check)) {
      // GD2 support is available.
      return TRUE;
    }
  }
  return FALSE;
}

/**
 * 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;
  }

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

  // Convert the hexadecimal background value to a color index value.
  if (isset($background)) {
    $rgb = array();
    for ($i = 16; $i >= 0; $i -= 8) {
      $rgb[] = (($background >> $i) & 0xFF);
    }
    $background = imagecolorallocatealpha($image->resource, $rgb[0], $rgb[1], $rgb[2], 0);
  }
  // Set the background color as transparent if $background is NULL.
  else {
    // Get the current transparent color.
    $background = imagecolortransparent($image->resource);

    // If no transparent colors, use white.
    if ($background == 0) {
      $background = imagecolorallocatealpha($image->resource, 255, 255, 255, 0);
    }
  }

  // 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') {
    $transparent_index = imagecolortransparent($image->resource);
    if ($transparent_index != 0) {
      $transparent_gif_color = imagecolorsforindex($image->resource, $transparent_index);
    }
  }

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

  // 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' . $extension;
  return (function_exists($function) && $image->resource = $function($image->source));
}

/**
 * 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') {
    // Grab transparent color index from image resource.
    $transparent = imagecolortransparent($image->resource);

    if ($transparent >= 0) {
      // The original must have a transparent color, allocate to the new image.
      $transparent_color = imagecolorsforindex($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, $transparent);
    }
  }
  elseif ($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;
  $data = getimagesize(drupal_realpath($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 "ingroup image".
 */

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