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imagecache_coloractions.module in ImageCache Actions 8

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coloractions/imagecache_coloractions.module
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<?php

/**
 * @file
 * Additional actions for imagecache processing.
 *
 * Exposes some of the simpler PHP 'imagefilter' actions (colorshift,
 * brightness, negative)
 * -  A transparency masker for merging with backgrounds.
 * -  A pseudo - file conversion feature.
 *
 * Compatible with the 2008 revision (imagecache 2)
 *
 * @author dan http://coders.co.nz
 * @author sydneyshan http://enigmadigital.net.au
 */
if (!function_exists('imagecache_actions_calculate_relative_position')) {
  module_load_include('inc', 'imagecache_actions', 'utility');
}
module_load_include('inc', 'imagecache_actions', 'utility-color');

// There is no way to specify a file in hook_image_effect_info,
// so placing this here for the time being.
include_once dirname(__FILE__) . '/transparency.inc';

/**
 * Implements hook_image_effect_info().
 *
 * Defines information about the supported effects.
 */
function imagecache_coloractions_image_effect_info() {

  // @todo: standardize naming. requires a hook_update_n().
  $effects = array();
  $effects['coloractions_colorshift'] = array(
    'label' => t('Color Shift'),
    'help' => t('Adjust image colors.'),
    'effect callback' => 'coloractions_colorshift_effect',
    'dimensions passthrough' => TRUE,
    'form callback' => 'coloractions_colorshift_form',
    'summary theme' => 'coloractions_colorshift_summary',
  );
  $effects['imagecache_coloroverlay'] = array(
    'label' => t('Color Overlay'),
    'help' => t('Apply a color tint to an image (retaining blacks and whites).'),
    'effect callback' => 'coloractions_coloroverlay_effect',
    'dimensions passthrough' => TRUE,
    'form callback' => 'coloractions_coloroverlay_form',
    'summary theme' => 'coloractions_coloroverlay_summary',
  );
  $effects['coloractions_brightness'] = array(
    'label' => t('Brightness'),
    'help' => t('Adjust image brightness.'),
    'effect callback' => 'coloractions_brightness_effect',
    'dimensions passthrough' => TRUE,
    'form callback' => 'coloractions_brightness_form',
    'summary theme' => 'coloractions_brightness_summary',
  );

  // @todo: changing inverse to invert at this place requires a hook_update_n().
  $effects['coloractions_inverse'] = array(
    'label' => t('Negative Image'),
    'help' => t('Invert colors and brightness.'),
    'effect callback' => 'coloractions_invert_effect',
    'dimensions passthrough' => TRUE,
    'form callback' => 'coloractions_invert_form',
    'summary theme' => 'coloractions_invert_summary',
  );

  // @todo Convert may need a little more work.
  $effects['coloractions_convert'] = array(
    'label' => t('Change file format'),
    'help' => t('Choose to save the image as a different filetype.'),
    'effect callback' => 'coloractions_convert_effect',
    'dimensions passthrough' => TRUE,
    'form callback' => 'coloractions_convert_form',
    'summary theme' => 'coloractions_convert_summary',
  );
  $effects['coloractions_posterize'] = array(
    'label' => t('Posterize'),
    'help' => t('Reduce the image to a limited number of color levels per channel.'),
    'effect callback' => 'coloractions_posterize_effect',
    'dimensions passthrough' => TRUE,
    'form callback' => 'coloractions_posterize_form',
    'summary theme' => 'coloractions_posterize_summary',
  );
  $effects['imagecache_alpha'] = array(
    'label' => t('Alpha Transparency'),
    'help' => t('Adjust transparency.'),
    'effect callback' => 'coloractions_alpha_effect',
    'dimensions passthrough' => TRUE,
    'form callback' => 'coloractions_alpha_form',
    'summary theme' => 'coloractions_alpha_summary',
  );
  $effects['imagecache_adjustlevels'] = array(
    'label' => t('Adjust Levels'),
    'help' => t('Adjust the color levels of the image.'),
    'effect callback' => 'coloractions_adjustlevels_effect',
    'dimensions passthrough' => TRUE,
    'form callback' => 'coloractions_adjustlevels_form',
    'summary theme' => 'coloractions_adjustlevels_summary',
  );
  $effects['imagecache_desaturatealpha'] = array(
    'label' => t('Desaturate Alpha'),
    'help' => t('Desaturate the image while retaining transparency.'),
    'effect callback' => 'coloractions_desaturatealpha_effect',
    'dimensions passthrough' => TRUE,
    'summary theme' => 'coloractions_desaturatealpha_summary',
  );
  return $effects;
}

/**
 * Implements hook_theme().
 *
 * Registers theme functions for the effect summaries.
 */
function imagecache_coloractions_theme() {
  return array(
    'coloractions_colorshift_summary' => array(
      'variables' => array(
        'data' => NULL,
      ),
    ),
    'coloractions_coloroverlay_summary' => array(
      'variables' => array(
        'data' => NULL,
      ),
    ),
    'coloractions_brightness_summary' => array(
      'variables' => array(
        'data' => NULL,
      ),
    ),
    'coloractions_convert_summary' => array(
      'variables' => array(
        'data' => NULL,
      ),
    ),
    'coloractions_posterize_summary' => array(
      'variables' => array(
        'data' => NULL,
      ),
    ),
    'coloractions_alpha_summary' => array(
      'variables' => array(
        'data' => NULL,
      ),
      'file' => 'transparency.inc',
    ),
    'coloractions_adjustlevels_summary' => array(
      'variables' => array(
        'data' => NULL,
      ),
    ),
    'coloractions_desaturatealpha_summary' => array(
      'variables' => array(
        'data' => NULL,
      ),
    ),
  );
}

/**
 * Implements hook_image_style_flush().
 *
 * This hook checks if the style contains a change format image effect and, if
 * so, creates an .htaccess file in the root of the derivative folder that
 * forces the correct Content-Type header on images served from that folder.
 *
 * @param array $style
 */
function imagecache_coloractions_image_style_flush($style) {
  if (!is_array($style)) {

    // See [#2190759].
    return;
  }

  // Error in core: the old style + set of effects is passed in. This means
  // that when a convert effect is added or deleted we won't notice. So we
  // "change" the order of execution by duplicating these lines from
  // image_style_flush():
  // Clear image style and effect caches.
  cache_clear_all('image_styles', 'cache');
  cache_clear_all('image_effects:', 'cache', TRUE);
  drupal_static_reset('image_styles');
  drupal_static_reset('image_effects');

  // Now load the current state of our style.
  $new_style = image_style_load(isset($style['name']) ? $style['name'] : NULL, isset($style['isid']) ? $style['isid'] : NULL);

  // If the style is flushed because it is being deleted it might be gone.
  if (is_array($new_style)) {

    // Now back to our actual work: determine if we have to crate an .htaccess
    // file.
    include_once dirname(__FILE__) . '/imagecache_coloractions.htaccess_creator.inc';
    imagecache_coloractions_create_htaccess_for_style($new_style);
  }
}

/**
 * Image effect form callback for the color shift effect.
 *
 * @param array $data
 *   The current configuration for this image effect.
 *
 * @return array
 *   The form definition for this effect.
 */
function coloractions_colorshift_form(array $data) {
  $defaults = array(
    'RGB' => array(
      'HEX' => '#FF0000',
    ),
  );
  $data = array_merge($defaults, (array) $data);
  $form = array(
    '#theme' => 'imagecache_rgb_form',
  );
  $form['RGB'] = imagecache_rgb_form($data['RGB']);
  $form['note'] = array(
    '#value' => t("<p>\n    Note that colorshift is a mathematical filter that doesn't always\n    have the expected result.\n    To shift an image precisely TO a target color,\n    desaturate (greyscale) it before colorizing.\n    The hue (color wheel) is the <em>direction</em> the\n    existing colors are shifted. The tone (inner box) is the amount.\n    Keep the tone half-way up the left site of the color box\n    for best results.\n  </p>"),
  );
  return $form;
}

/**
 * Implements theme_hook() for the color shift effect summary.
 *
 * @param array $variables
 *   An associative array containing:
 *   - data: The current configuration for this image effect.
 *
 * @return string
 *   The HTML for the summary of this image effect.
 * @ingroup themeable
 */
function theme_coloractions_colorshift_summary(array $variables) {
  return theme_imagecacheactions_rgb($variables['data']);
}

/**
 * Image effect callback for the color shift effect.
 *
 * @param stdClass $image
 * @param array $data
 *
 * @return bool
 *   true on success, false otherwise.
 */
function coloractions_colorshift_effect(stdClass $image, array $data) {

  // convert color from hex (as it is stored in the UI)
  if ($data['RGB']['HEX'] && ($deduced = imagecache_actions_hex2rgba($data['RGB']['HEX']))) {
    $data['RGB'] = array_merge($data['RGB'], $deduced);
  }
  return image_toolkit_invoke('colorshift', $image, array(
    $data,
  ));
}

/**
 * GD toolkit specific implementation of the color shift effect.
 *
 * @param stdClass $image
 * @param array $data
 *   The parameters for this effect.
 *
 * @return bool
 *   true on success, false otherwise.
 */
function image_gd_colorshift(stdClass $image, array $data) {
  $RGB = $data['RGB'];
  if (!function_exists('imagefilter')) {
    module_load_include('inc', 'imagecache_actions', 'imagefilter');
  }
  return imagefilter($image->resource, 4, $RGB['red'], $RGB['green'], $RGB['blue']);
}

/**
 * Imagemagick toolkit specific implementation of the color shift effect.
 *
 * @param stdClass $image
 * @param array $data
 *   The parameters for this effect.
 *
 * @return bool
 *   true on success, false otherwise.
 */
function image_imagemagick_colorshift(stdClass $image, array $data) {
  $RGB = $data['RGB'];
  $image->ops[] = "-fill rgb" . escapeshellcmd('(') . "{$RGB['red']},{$RGB['green']},{$RGB['blue']}" . escapeshellcmd(')') . " -colorize 50" . escapeshellcmd('%');
  return TRUE;
}

/**
 * Image effect form callback for the color overlay effect.
 *
 * @param array $data
 *   The current configuration for this image effect.
 *
 * @return array
 *   The form definition for this effect.
 */
function coloractions_coloroverlay_form(array $data) {
  $defaults = array(
    'RGB' => array(
      'HEX' => '#E2DB6A',
    ),
  );
  $data = array_merge($defaults, (array) $data);
  $form = array(
    '#theme' => 'imagecache_rgb_form',
  );
  $form['RGB'] = imagecache_rgb_form($data['RGB']);
  $form['note'] = array(
    '#value' => t("<p>\n    Note that color overlay is a mathematical filter that doesn't always\n    have the expected result.\n    To shift an image precisely TO a target color,\n    desaturate (greyscale) it before colorizing.\n    The hue (color wheel) is the <em>direction</em> the\n    existing colors are shifted. The tone (inner box) is the amount.\n    Keep the tone half-way up the left site of the color box\n    for best results.\n    </p>"),
  );
  return $form;
}

/**
 * Implements theme_hook() for the color overlay effect summary.
 *
 * @param array $variables
 *   An associative array containing:
 *   - data: The current configuration for this image effect.
 *
 * @return string
 *   The HTML for the summary of this image effect.
 * @ingroup themeable
 */
function theme_coloractions_coloroverlay_summary(array $variables) {
  return theme_imagecacheactions_rgb($variables['data']);
}

/**
 * Image effect callback for the color overlay effect.
 *
 * @param stdClass $image
 * @param array $data
 *
 * @return bool
 *   true on success, false otherwise.
 */
function coloractions_coloroverlay_effect(stdClass $image, array $data) {

  // convert color from hex (as it is stored in the UI)
  if ($data['RGB']['HEX'] && ($deduced = imagecache_actions_hex2rgba($data['RGB']['HEX']))) {
    $data['RGB'] = array_merge($data['RGB'], $deduced);
  }
  return image_toolkit_invoke('coloroverlay', $image, array(
    $data,
  ));
}

/**
 * GD toolkit specific implementation of the color overlay effect.
 *
 * @param stdClass $image
 * @param array $data
 *   The parameters for this effect.
 *
 * @return bool
 *   true on success, false otherwise.
 */
function image_gd_coloroverlay(stdClass $image, array $data) {
  $RGB = $data['RGB'];
  $w = $image->info['width'];
  $h = $image->info['height'];
  for ($y = 0; $y < $h; $y++) {
    for ($x = 0; $x < $w; $x++) {
      $rgb = imagecolorat($image->resource, $x, $y);
      $source = imagecolorsforindex($image->resource, $rgb);
      if ($source['red'] <= 128) {
        $final_r = 2 * $source['red'] * $RGB['red'] / 256;
      }
      else {
        $final_r = 255 - (255 - 2 * ($source['red'] - 128)) * (255 - $RGB['red']) / 256;
      }
      if ($source['green'] <= 128) {
        $final_g = 2 * $source['green'] * $RGB['green'] / 256;
      }
      else {
        $final_g = 255 - (255 - 2 * ($source['green'] - 128)) * (255 - $RGB['green']) / 256;
      }
      if ($source['blue'] <= 128) {
        $final_b = 2 * $source['blue'] * $RGB['blue'] / 256;
      }
      else {
        $final_b = 255 - (255 - 2 * ($source['blue'] - 128)) * (255 - $RGB['blue']) / 256;
      }
      $final_colour = imagecolorallocatealpha($image->resource, $final_r, $final_g, $final_b, $source['alpha']);
      imagesetpixel($image->resource, $x, $y, $final_colour);
    }
  }
  return TRUE;
}

/**
 * Imagemagick toolkit specific implementation of the color overlay effect.
 *
 * @param stdClass $image
 * @param array $data
 *   The parameters for this effect.
 *
 * @return bool
 *   true on success, false otherwise.
 */
function image_imagemagick_coloroverlay(stdClass $image, array $data) {
  $RGB = $data['RGB'];
  $image->ops[] = escapeshellcmd('(') . " +clone +matte -fill rgb" . escapeshellcmd('(') . "{$RGB['red']},{$RGB['green']},{$RGB['blue']}" . escapeshellcmd(')') . " -colorize 100" . escapeshellcmd('%') . " +clone +swap -compose overlay -composite " . escapeshellcmd(')') . " -compose SrcIn -composite";
  return TRUE;
}

/**
 * Image effect form callback for the brightness effect.
 *
 * @param array $data
 *   The current configuration for this image effect.
 *
 * @return array
 *   The form definition for this effect.
 */
function coloractions_brightness_form(array $data) {
  $default = array(
    'filter_arg1' => '100',
  );
  $data = array_merge($default, (array) $data);
  $form = array();
  $form['help'] = array(
    '#value' => t("The brightness effect seldom looks good on its own, but can be useful to wash out an image before making it transparent - eg for a watermark."),
  );
  $form['filter_arg1'] = array(
    '#type' => 'textfield',
    '#title' => t('Brightness'),
    '#description' => t('-255 - +255'),
    '#default_value' => $data['filter_arg1'],
    '#size' => 3,
  );
  return $form;
}

/**
 * Implements theme_hook() for the brightness effect summary.
 *
 * @param array $variables
 *   An associative array containing:
 *   - data: The current configuration for this image effect.
 *
 * @return string
 *   The HTML for the summary of this image effect.
 * @ingroup themeable
 */
function theme_coloractions_brightness_summary(array $variables) {
  return t("Adjust") . " : " . $variables['data']['filter_arg1'];
}

/**
 * Image effect callback for the brightness effect.
 *
 * @param stdClass $image
 * @param array $data
 *
 * @return bool
 *   true on success, false otherwise.
 */
function coloractions_brightness_effect(stdClass $image, array $data) {
  return image_toolkit_invoke('brightness', $image, array(
    $data,
  ));
}

/**
 * GD toolkit specific implementation of the brightness effect.
 *
 * @param stdClass $image
 * @param array $data
 *   The parameters for this effect.
 *
 * @return bool
 *   true on success, false otherwise.
 */
function image_gd_brightness(stdClass $image, array $data) {
  if (!function_exists('imagefilter')) {
    module_load_include('inc', 'imagecache_actions', 'imagefilter');
  }
  return imagefilter($image->resource, 2, $data['filter_arg1']);
}

/**
 * Imagemagick toolkit specific implementation of the brightness effect.
 *
 * @param stdClass $image
 * @param array $data
 *   The parameters for this effect.
 *
 * @return bool
 *   true on success, false otherwise.
 */
function image_imagemagick_brightness(stdClass $image, array $data) {
  $image->ops[] = "-modulate " . (int) (100 + $data['filter_arg1'] / 128 * 100);
  return TRUE;
}

/**
 * Image effect form callback for the image invert effect.
 *
 * This effect has no parameters.
 *
 * param array $data
 *   The current configuration for this image effect.
 *
 * @return array
 *   The form definition for this effect.
 */
function coloractions_invert_form() {
  $form = array();
  return $form;
}

/**
 * Image effect callback for the image invert effect.
 *
 * @param stdClass $image
 * @param array $data
 *
 * @return bool
 *   true on success, false otherwise.
 */
function coloractions_invert_effect(stdClass $image, array $data) {
  return image_toolkit_invoke('invert', $image, array(
    $data,
  ));
}

/**
 * GD toolkit specific implementation of the image invert effect.
 *
 * @param stdClass $image
 *  param array $data
 *   The parameters for this effect.
 *
 * @return bool
 *   true on success, false otherwise.
 */
function image_gd_invert(stdClass $image) {
  if (!function_exists('imagefilter')) {
    module_load_include('inc', 'imagecache_actions', 'imagefilter');
  }
  return imagefilter($image->resource, 0);
}

/**
 * Imagemagick toolkit specific implementation of the image invert effect.
 *
 * param stdClass $image
 * param array $data
 *   The parameters for this effect.
 *
 * @return bool
 *   true on success, false otherwise.
 */
function image_imagemagick_invert() {

  // @todo
  return FALSE;
}

/**
 * Image effect form callback for the convert image format effect.
 *
 * @param array $data
 *   The current configuration for this image effect.
 *
 * @return array
 *   The form definition for this effect.
 */
function coloractions_convert_form(array $data) {
  $defaults = array(
    'format' => 'image/png',
    'quality' => '75',
  );
  $data = array_merge($defaults, $data);
  $form = array(
    'help' => array(
      '#markup' => t("If you've been using transparencies in the process, the result may get saved as a PNG (as the image was treated as a one in in-between processes). If this is not desired (file sizes may get too big) you should use this process to force a flatten action before saving. "),
    ),
    'help2' => array(
      '#markup' => t("For technical reasons, changing the file format within imagecache does <em>not</em> change the filename suffix. A png may be saved as a *.jpg or vice versa. This may confuse some browsers and image software, but most of them have no trouble. "),
    ),
    'format' => array(
      '#title' => t("File format"),
      '#type' => 'select',
      '#default_value' => isset($data['format']) ? $data['format'] : 'image/png',
      '#options' => coloractions_file_formats(),
    ),
    'quality' => array(
      '#type' => 'textfield',
      '#title' => t('Quality'),
      '#description' => t('Override the default image quality. Works for Imagemagick only. Ranges from 0 to 100. For jpg, higher values mean better image quality but bigger files. For png it is a combination of compression and filter'),
      '#size' => 10,
      '#maxlength' => 3,
      '#default_value' => $data['quality'],
      '#field_suffix' => '%',
    ),
  );
  return $form;
}

/**
 * Implements theme_hook() for the convert image format effect summary.
 *
 * @param array $variables
 *   An associative array containing:
 *   - data: The current configuration for this image effect.
 *
 * @return string
 *   The HTML for the summary of this image effect.
 * @ingroup themeable
 */
function theme_coloractions_convert_summary($variables) {
  $data = $variables['data'];
  $formats = coloractions_file_formats();
  if ($formats[$data['format']] == 'jpg') {
    return t('Convert to: @format, quality: @quality%', array(
      '@format' => $formats[$data['format']],
      '@quality' => $data['quality'],
    ));
  }
  else {
    return t("Convert to") . ": " . $formats[$data['format']];
  }
}

/**
 * Image effect callback for the convert image format effect.
 *
 * @param stdClass $image
 * @param array $data
 *
 * @return bool
 *   true on success, false otherwise.
 */
function coloractions_convert_effect(stdClass $image, array $data) {
  $formats = coloractions_file_formats();
  $image->info['mime_type'] = $data['format'];
  $image->info['extension'] = $formats[$data['format']];
  image_toolkit_invoke('convert', $image, array(
    $data,
  ));
  return TRUE;
}

/**
 * GD toolkit specific implementation of the convert image format effect.
 *
 * param stdClass $image
 * param array $data
 *   The parameters for this effect.
 *
 * @return bool
 *   true on success, false otherwise.
 */
function image_gd_convert() {
  return TRUE;
}

/**
 * Imagemagick toolkit specific implementation of the color shift effect.
 *
 * Converting the image format with imagemagick is done by prepending the output
 * format to the target file separated by a colon (:). This is done with
 * hook_imagemagick_arguments_alter(), see below.
 *
 * @param stdClass $image
 * @param array $data
 *   The parameters for this effect.
 *
 * @return bool
 *   true on success, false otherwise.
 */
function image_imagemagick_convert(stdClass $image, array $data) {
  $image->ops['output_format'] = $image->info['extension'];
  $image->ops['custom_quality_value'] = (int) $data['quality'];
  return TRUE;
}

/**
 * Implements hook_imagemagick_arguments_alter().
 *
 * This hook moves a change in output format from the args (action list) to the
 * destination format setting within the context.
 */
function imagecache_coloractions_imagemagick_arguments_alter(&$args, &$context) {
  if (isset($args['output_format'])) {
    $context['destination_format'] = $args['output_format'];
    unset($args['output_format']);
  }
  if (isset($args['custom_quality_value'])) {
    $args['quality'] = sprintf('-quality %d', $args['custom_quality_value']);
    unset($args['custom_quality_value']);
  }
}

/**
 * Mini mime-type list
 *
 * image_type_to_extension and image_type_to_mime_type?
 */
function coloractions_file_formats() {
  return array(
    'image/jpeg' => 'jpg',
    'image/gif' => 'gif',
    'image/png' => 'png',
  );
}

/**
 * Image effect form callback for the posterize effect.
 *
 * @param array $data
 *   The current configuration for this image effect.
 *
 * @return array
 *   The form definition for this effect.
 */
function coloractions_posterize_form(array $data) {
  $form = array();
  $form['colors'] = array(
    '#type' => 'textfield',
    '#title' => t('Color levels per channel'),
    '#default_value' => isset($data['colors']) ? $data['colors'] : '',
    '#required' => TRUE,
    '#size' => 10,
    '#element_validate' => array(
      'image_effect_integer_validate',
    ),
    '#allow_negative' => FALSE,
    '#description' => t('Number of unique values per color channel to reduce this image to. The transparency channel is left unchanged. This effect can be used to reduce file size on png images.'),
  );
  return $form;
}

/**
 * Implements theme_hook() for the posterize effect summary.
 *
 * @param array $variables
 *   An associative array containing:
 *   - data: The current configuration for this image effect.
 *
 * @return string
 *   The HTML for the summary of this image effect.
 * @ingroup themeable
 */
function theme_coloractions_posterize_summary(array $variables) {
  return t(': Reduce to @colors color levels per channel', array(
    '@colors' => $variables['data']['colors'],
  ));
}

/**
 * Image effect callback for the posterize effect.
 *
 * @param stdClass $image
 * @param array $data
 *
 * @return bool
 *   true on success, false otherwise.
 */
function coloractions_posterize_effect(stdClass $image, array $data) {
  if (!image_toolkit_invoke('posterize', $image, array(
    $data['colors'],
  ))) {
    watchdog('imagecache_actions', 'Image posterize failed using the %toolkit toolkit on %path (%mimetype, %dimensions)', array(
      '%toolkit' => $image->toolkit,
      '%path' => $image->source,
      '%mimetype' => $image->info['mime_type'],
      '%dimensions' => $image->info['height'] . 'x' . $image->info['height'],
    ), WATCHDOG_ERROR);
    return FALSE;
  }
  return TRUE;
}

/**
 * GD toolkit specific implementation of the posterize effect.
 *
 * Based on:
 * http://www.qtcentre.org/threads/36385-Posterizes-an-image-with-results-identical-to-Gimp-s-Posterize-command?p=167712#post167712
 *
 * @param stdClass $image
 * @param int $colors
 *   The parameter for this effect.
 *
 * @return bool
 *   true on success, false otherwise.
 */
function image_gd_posterize(stdClass $image, $colors) {

  // Value step for colors per channel.
  $round_to = 255 / ($colors - 1);
  $alpha_bit_mask = 255 << 24;
  for ($x = imagesx($image->resource); $x--;) {
    for ($y = imagesy($image->resource); $y--;) {
      $rgb = imagecolorat($image->resource, $x, $y);

      // Use bitmasks to extract numbers we want, faster equivalent to imagecolorsforindex().
      $a = $rgb & $alpha_bit_mask;

      // Alpha
      $r = $rgb >> 16 & 255;

      // Red
      $g = $rgb >> 8 & 255;

      // Green
      $b = $rgb & 255;

      // Blue
      // (int) (value + 0.5) faster equivalent to round() and already an int.
      $new_r = (int) ((int) ($r / $round_to + 0.5) * $round_to + 0.5);
      $new_g = (int) ((int) ($g / $round_to + 0.5) * $round_to + 0.5);
      $new_b = (int) ((int) ($b / $round_to + 0.5) * $round_to + 0.5);

      // Faster equivalent to imagecolorallocatealpha().
      $color_combined = $a | $new_r << 16 | $new_g << 8 | $new_b;
      imagesetpixel($image->resource, $x, $y, $color_combined);
    }
  }
  return TRUE;
}

/**
 * Imagemagick toolkit specific implementation of the color shift effect.
 *
 * @param stdClass $image
 * @param int $colors
 *   The parameter for this effect.
 *
 * @return bool
 *   true on success, false otherwise.
 */
function image_imagemagick_posterize(stdClass $image, $colors) {

  // In newer versions of ImageMagick dithering has no effect on posterize.
  // Turn dithering off on older versions of ImageMagick for consistency.
  $image->ops[] = ' +dither -posterize ' . (int) $colors;
  return TRUE;
}

/**
 * Image effect form callback for the brightness effect.
 *
 * Settings for color level adjustment actions.
 *
 * @param array $data
 *   The current configuration for this image effect.
 *
 * @return array
 *   The form definition for this effect.
 */
function coloractions_adjustlevels_form(array $data) {
  $defaults = array(
    'independent_colors' => FALSE,
    'all_colors' => array(
      'low' => 0,
      'high' => 1,
    ),
    'per_color' => array(
      'low_red' => 0,
      'high_red' => 1,
      'low_green' => 0,
      'high_green' => 1,
      'low_blue' => 0,
      'high_blue' => 1,
    ),
  );
  $data = array_merge($defaults, $data);
  $form = array(
    '#type' => 'container',
    'help' => array(
      '#type' => 'markup',
      '#markup' => t("<p>Adjusting color levels scales the given channels to a range specified by the 'low' and 'high' values.\n      These 'low' and 'high' values can be any value between 0 and 1.\n      E.g. assume that 'low' is 0.2 and 'high' is 0.9.\n      Pixels that had a value of 0, will get a value of 0.2 * 255 = 51 and pixels that had a value of 255, will get a value of 0.9 * 255 = 229.</p>\n      <p>Note that color level adjustment is a mathematical filter and a such doesn't do automatic balancing.</p>"),
    ),
    '#element_validate' => array(
      'coloractions_validate_form',
    ),
  );
  $form['independent_colors'] = array(
    '#type' => 'checkbox',
    '#title' => t('Set each color independently'),
    '#default_value' => $data['independent_colors'],
  );
  $form['all_colors'] = array(
    '#type' => 'container',
    '#tree' => TRUE,
    '#title' => t('All colors range'),
    '#required' => !$data['independent_colors'],
    '#states' => array(
      'visible' => array(
        ':input[name="data[independent_colors]"]' => array(
          'checked' => FALSE,
        ),
      ),
      'required' => array(
        ':input[name="data[independent_colors]"]' => array(
          'checked' => FALSE,
        ),
      ),
    ),
  );
  $form['all_colors'] += coloractions_adjustlevels_form_helper(array(
    'low' => array(
      'title' => t('Low'),
      'default' => $data['all_colors']['low'],
    ),
    'high' => array(
      'title' => t('High'),
      'default' => $data['all_colors']['high'],
    ),
  ));
  $form['per_color'] = array(
    '#type' => 'container',
    '#tree' => TRUE,
    '#title' => t('Individual Color Ranges'),
    '#required' => $data['independent_colors'],
    '#states' => array(
      'visible' => array(
        ':input[name="data[independent_colors]"]' => array(
          'checked' => TRUE,
        ),
      ),
      'required' => array(
        ':input[name="data[independent_colors]"]' => array(
          'checked' => TRUE,
        ),
      ),
    ),
  );
  $form['per_color'] += coloractions_adjustlevels_form_helper(array(
    'low_red' => array(
      'title' => t('Red Low'),
      'default' => $data['per_color']['low_red'],
    ),
    'high_red' => array(
      'title' => t('Red High'),
      'default' => $data['per_color']['high_red'],
    ),
    'low_green' => array(
      'title' => t('Green Low'),
      'default' => $data['per_color']['low_green'],
    ),
    'high_green' => array(
      'title' => t('Green High'),
      'default' => $data['per_color']['high_green'],
    ),
    'low_blue' => array(
      'title' => t('Blue Low'),
      'default' => $data['per_color']['low_blue'],
    ),
    'high_blue' => array(
      'title' => t('Blue High'),
      'default' => $data['per_color']['high_blue'],
    ),
  ));
  return $form;
}

/**
 * Helper function to create the form for the color level adjustment effect.
 *
 * @param array $data
 *   Array containing the form elements
 *   names as keys for array elements containing title and default value.
 *
 * @return array
 */
function coloractions_adjustlevels_form_helper(array $data) {
  $form = array();
  foreach ($data as $name => $value) {
    $form[$name] = array(
      '#type' => 'textfield',
      '#title' => $value['title'],
      '#default_value' => $value['default'],
      '#size' => 5,
      '#element_validate' => array(
        'coloractions_validate_scale_0_1',
      ),
    );
  }
  return $form;
}

/**
 * Form element validation handler for elements that should contain a number
 * between 0 and 1.
 */
function coloractions_validate_scale_0_1($element) {
  $value = $element['#value'];
  if ($value != '' && (!is_numeric($value) || (double) $value > 1.0 || (double) $value < 0.0)) {
    form_error($element, t('%name must be a value between 0 and 1.', array(
      '%name' => $element['#title'],
    )));
  }
}

/**
 * Form element validation handler that compares low and high values.
 */
function coloractions_validate_form($element) {
  $independent_colors = !empty($element['independent_colors']['#value']);
  if (!$independent_colors) {

    // Compare low and high.
    coloractions_validate_low_and_high($element, 'all_colors', '');
  }
  else {

    // Compare low and high per color
    coloractions_validate_low_and_high($element, 'per_color', '_red');
    coloractions_validate_low_and_high($element, 'per_color', '_green');
    coloractions_validate_low_and_high($element, 'per_color', '_blue');
  }
}
function coloractions_validate_low_and_high($element, $fieldset, $suffix) {
  if ((double) $element[$fieldset]["low{$suffix}"]['#value'] > (double) $element[$fieldset]["high{$suffix}"]['#value']) {
    form_error($element[$fieldset]["high{$suffix}"], t('%name-high must be higher then %name-low.', array(
      '%name-high' => $element[$fieldset]["high{$suffix}"]['#title'],
      '%name-low' => $element[$fieldset]["low{$suffix}"]['#title'],
    )));
  }
}

/**
 * Implements theme_hook() for the adjust color levels effect summary.
 *
 * @param array $variables
 *   An associative array containing:
 *   - data: The current configuration for this image effect.
 *
 * @return string
 *   The HTML for the summary of this image effect.
 * @ingroup themeable
 */
function theme_coloractions_adjustlevels_summary(array $variables) {
  $data = $variables['data'];
  if (empty($data['independent_colors'])) {
    return t('@range', array(
      '@range' => "[{$data['all_colors']['low']} - {$data['all_colors']['high']}]",
    ));
  }
  else {
    return t('red: @red-range, green: @green-range, blue: @blue-range', array(
      '@red-range' => "[{$data['per_color']['low_red']} - {$data['per_color']['high_red']}]",
      '@green-range' => "[{$data['per_color']['low_green']} - {$data['per_color']['high_green']}]",
      '@blue-range' => "[{$data['per_color']['low_blue']} - {$data['per_color']['high_blue']}]",
    ));
  }
}

/**
 * Image effect callback for the adjust levels effect.
 *
 * @param stdClass $image
 * @param array $data
 *
 * @return bool
 *   true on success, false otherwise.
 */
function coloractions_adjustlevels_effect(stdClass $image, array $data) {
  return image_toolkit_invoke('adjustlevels', $image, array(
    $data,
  ));
}

/**
 * GD toolkit specific implementation of the adjust levels effect.
 *
 * @param stdClass $image
 * @param array $data
 *   The parameters for this effect.
 *
 * @return bool
 *   true on success, false otherwise.
 */
function image_gd_adjustlevels(stdClass $image, array $data) {
  $width = $image->info['width'];
  $height = $image->info['height'];
  if ($data['independent_colors']) {
    $lower_r = $data['per_color']['low_red'] * 255;
    $factor_r = ($data['per_color']['high_red'] * 255 - $lower_r) / 255;
    $lower_g = $data['per_color']['low_green'] * 255;
    $factor_g = ($data['per_color']['high_green'] * 255 - $lower_g) / 255;
    $lower_b = $data['per_color']['low_blue'] * 255;
    $factor_b = ($data['per_color']['high_blue'] * 255 - $lower_b) / 255;
  }
  else {
    $lower_r = $lower_g = $lower_b = $data['all_colors']['low'] * 255;
    $factor_r = $factor_g = $factor_b = ($data['all_colors']['high'] * 255 - $lower_r) / 255;
  }
  for ($y = 0; $y < $height; $y++) {
    for ($x = 0; $x < $width; $x++) {
      $rgb = imagecolorat($image->resource, $x, $y);
      $source = imagecolorsforindex($image->resource, $rgb);
      $final_r = $lower_r + $factor_r * $source['red'];
      $final_g = $lower_g + $factor_g * $source['green'];
      $final_b = $lower_b + $factor_b * $source['blue'];
      $final_colour = imagecolorallocatealpha($image->resource, $final_r, $final_g, $final_b, $source['alpha']);
      imagesetpixel($image->resource, $x, $y, $final_colour);
    }
  }
  return TRUE;
}

/**
 * Implements theme_hook() for the desaturate alpha effect summary.
 *
 * param array $variables
 *   An associative array containing:
 *   - data: The current configuration for this image effect.
 *
 * @return string
 *   The HTML for the summary of this image effect.
 * @ingroup themeable
 */
function theme_coloractions_desaturatealpha_summary() {
  return t(': Desaturates the image while retaining transparency.');
}

/**
 * Image effect callback for the desaturate alpha effect.
 *
 * @param stdClass $image
 * @param array $data
 *
 * @return bool
 *   true on success, false otherwise.
 */
function coloractions_desaturatealpha_effect(stdClass $image, array $data) {
  return image_toolkit_invoke('desaturatealpha', $image, array(
    $data,
  ));
}

/**
 * GD toolkit specific implementation of the adjust levels effect.
 *
 * @param stdClass $image
 *  param array $data
 *   The parameters for this effect.
 *
 * @return bool
 *   true on success, false otherwise.
 */
function image_gd_desaturatealpha(stdClass $image) {
  imagealphablending($image->resource, FALSE);
  $result = imagefilter($image->resource, IMG_FILTER_GRAYSCALE);
  imagealphablending($image->resource, TRUE);
  return $result;
}

Functions

Namesort descending Description
coloractions_adjustlevels_effect Image effect callback for the adjust levels effect.
coloractions_adjustlevels_form Image effect form callback for the brightness effect.
coloractions_adjustlevels_form_helper Helper function to create the form for the color level adjustment effect.
coloractions_brightness_effect Image effect callback for the brightness effect.
coloractions_brightness_form Image effect form callback for the brightness effect.
coloractions_coloroverlay_effect Image effect callback for the color overlay effect.
coloractions_coloroverlay_form Image effect form callback for the color overlay effect.
coloractions_colorshift_effect Image effect callback for the color shift effect.
coloractions_colorshift_form Image effect form callback for the color shift effect.
coloractions_convert_effect Image effect callback for the convert image format effect.
coloractions_convert_form Image effect form callback for the convert image format effect.
coloractions_desaturatealpha_effect Image effect callback for the desaturate alpha effect.
coloractions_file_formats Mini mime-type list
coloractions_invert_effect Image effect callback for the image invert effect.
coloractions_invert_form Image effect form callback for the image invert effect.
coloractions_posterize_effect Image effect callback for the posterize effect.
coloractions_posterize_form Image effect form callback for the posterize effect.
coloractions_validate_form Form element validation handler that compares low and high values.
coloractions_validate_low_and_high
coloractions_validate_scale_0_1 Form element validation handler for elements that should contain a number between 0 and 1.
imagecache_coloractions_imagemagick_arguments_alter Implements hook_imagemagick_arguments_alter().
imagecache_coloractions_image_effect_info Implements hook_image_effect_info().
imagecache_coloractions_image_style_flush Implements hook_image_style_flush().
imagecache_coloractions_theme Implements hook_theme().
image_gd_adjustlevels GD toolkit specific implementation of the adjust levels effect.
image_gd_brightness GD toolkit specific implementation of the brightness effect.
image_gd_coloroverlay GD toolkit specific implementation of the color overlay effect.
image_gd_colorshift GD toolkit specific implementation of the color shift effect.
image_gd_convert GD toolkit specific implementation of the convert image format effect.
image_gd_desaturatealpha GD toolkit specific implementation of the adjust levels effect.
image_gd_invert GD toolkit specific implementation of the image invert effect.
image_gd_posterize GD toolkit specific implementation of the posterize effect.
image_imagemagick_brightness Imagemagick toolkit specific implementation of the brightness effect.
image_imagemagick_coloroverlay Imagemagick toolkit specific implementation of the color overlay effect.
image_imagemagick_colorshift Imagemagick toolkit specific implementation of the color shift effect.
image_imagemagick_convert Imagemagick toolkit specific implementation of the color shift effect.
image_imagemagick_invert Imagemagick toolkit specific implementation of the image invert effect.
image_imagemagick_posterize Imagemagick toolkit specific implementation of the color shift effect.
theme_coloractions_adjustlevels_summary Implements theme_hook() for the adjust color levels effect summary.
theme_coloractions_brightness_summary Implements theme_hook() for the brightness effect summary.
theme_coloractions_coloroverlay_summary Implements theme_hook() for the color overlay effect summary.
theme_coloractions_colorshift_summary Implements theme_hook() for the color shift effect summary.
theme_coloractions_convert_summary Implements theme_hook() for the convert image format effect summary.
theme_coloractions_desaturatealpha_summary Implements theme_hook() for the desaturate alpha effect summary.
theme_coloractions_posterize_summary Implements theme_hook() for the posterize effect summary.