<?php
/**
 * @file Helper functions for the text2canvas action for imagecache
 *
 * @author Dan Morrison http://coders.co.nz
 *
 * Individually configurable rounded corners logic contributed by canaryMason
 * 2009 03 http://drupal.org/node/402112
 *
 * Better algorithm for trimming rounded corners from donquixote
 * 2009 09 http://drupal.org/node/564036
 *
 */

if (! function_exists('image_overlay') ) {
  module_load_include('inc', 'imagecache_actions', 'image_overlay');
}
if (! function_exists('imagecache_actions_pos_form') ) {
  module_load_include('inc', 'imagecache_actions', 'utility-form');
}
if (! function_exists('imagecache_actions_keyword_filter') ) {
  module_load_include('inc', 'imagecache_actions', 'utility');
}

////////////////////////////////////////////////
// IMAGEMASK

/**
 * Use a given image to mask the current canvas
 *
 * Implementation of imagecache_hook_form()
 *
 * @param $data array of settings for this action
 * @return a form definition
 */
function canvasactions_imagemask_form($data) {
  // TODO: add offset/positioning/scaling support - currently the mask is applied to the supplied image without resizing and positioned at (0,0)
  $form = array();
  $form['effect_help_text'] = array(
    '#type' => 'item',
    '#title' => t('Image mask'),
    '#description' => t('<p>This effect will add (or replace) a
transparency channel to your image, thereby converting it to a 32 bit PNG.
The mask file should be a grayscale image where black is fully transparent and
white is fully opaque. The referenced mask will be applied to the top left of
the image.</p>'),
  );

	$form['path'] = array(
    '#type' => 'textfield',
    '#title' => t('Mask file name'),
    '#default_value' => isset($data['path']) ? $data['path'] : '',
    '#description' => imagecache_actions_file_field_description(),
    '#element_validate' => array('imagecache_actions_validate_file'),
  );
  return $form;
}

/**
 * Implementation of theme_hook() for imagecache_ui.module
 */
function theme_canvasactions_imagemask_summary($variables) {
  $data = $variables['data'];
  return 'file: ' . $data['path'];
}

/**
 * Apply the given image file to the canvas as a mask
 *
 * Implementation of hook_image()
 *
 * @param $image
 * @param $data
 */
function canvasactions_imagemask_image(&$image, $data = array()) {
  $mask = imagecache_actions_image_load($data['path'], $image->toolkit);
  if ($mask) {
    // TODO: (sydneyshan) Consider best way to add offset support - I assume we
    // would position the mask somewhere (top/left/offset px etc) and choose if
    // the surrounding area is white or black (opaque or transparent) using an
    // extra form element (radio). Assess exsiting positioning code first to
    // reduce duplication of code. Pass the results to the following function as
    // array($mask, $data). Perhaps add a 'scale mask to fit image'/'scale image
    // to fit mask'/'no scale' radio group?
    return image_toolkit_invoke('imagemask', $image, array($mask));
  }
  return FALSE;
}

/**
 * Apply an image-based transparency mask using GD.
 *
 * &$image is an array expected to contain the details of the image to be masked
 * $mask is an array expected to contain the details of the mask image
 */
function image_gd_imagemask($image, $mask = array()) {

	$newPicture = imagecreatetruecolor( $image->info['width'], $image->info['height'] );
	imagesavealpha( $newPicture, true );
  imagealphablending( $newPicture, true);
  $transparent = imagecolorallocatealpha( $newPicture, 0, 0, 0, 127 );
	imagefill( $newPicture, 0, 0, $transparent);

	// Perform pixel-based alpha map application
	for( $x = 0; $x < $image->info['width']; $x++ ) {
	  for( $y = 0; $y < $image->info['height']; $y++ ) {
	    // Deal with images with mismatched sizes
	    if ($x >= $mask->info['width'] || $y >= $mask->info['height'] ) {
  	    imagesetpixel( $newPicture, $x, $y, $transparent );
	    }
	    else {
  	    $alpha = imagecolorsforindex( $mask->resource, imagecolorat( $mask->resource, $x, $y ) );
  	    $alpha = 127 - floor( $alpha[ 'red' ] / 2 );
  	    $color = imagecolorsforindex( $image->resource, imagecolorat( $image->resource, $x, $y ) );
  	    imagesetpixel( $newPicture, $x, $y, imagecolorallocatealpha( $newPicture, $color[ 'red' ], $color[ 'green' ], $color[ 'blue' ], $alpha ) );
	    }
	  }
	}

	// Copy back to original picture
	imagedestroy( $image->resource );
	$image->resource = $newPicture;

  return TRUE;
}

/**
 * Apply an image-based transparency mask using ImageMagick.
 *
 * &$image is an array expected to contain the details of the image to be masked
 * $mask is an array expected to contain the details of the mask image
 */
function image_imagemagick_imagemask($image, $mask = NULL) {
  $image->ops[] = escapeshellarg($mask->source) . ' -alpha Off -compose CopyOpacity -composite';
  return TRUE;
}

////////////////////////////////////////////////


/**
 * Implementation of imagecache_hook_form()
 *
 * Settings for preparing a canvas.
 *
 * @param $data array of settings for this action
 * @return a form definition
 */
function canvasactions_definecanvas_form($data) {
  module_load_include('inc', 'imagecache_actions', 'utility-color');
  $defaults = array(
    'RGB' => array(
      'HEX' => '#333333',
    ),
    'under' => TRUE,
    'exact' => array(
      'width' => '',
      'height' => '',
      'xpos' => 'center',
      'ypos' => 'center',
    ),
    'relative' => array(
      'leftdiff' => '',
      'rightdiff' => '',
      'topdiff' => '',
      'bottomdiff' => '',
    ),
  );
  $data = array_merge($defaults, (array) $data);

  $form = array(
    'RGB' => imagecache_rgb_form($data['RGB']),
    'help' => array(
      '#type' => 'markup',
      '#value' => t('Enter no color value for transparent. This will have the effect of adding clear margins around the image.'),
      '#prefix' => '<p>',
      '#suffix' => '</p>',
    ),
    'under' => array(
      '#type' => 'checkbox',
      '#title' => t('Resize canvas <em>under</em> image (possibly cropping)'),
      '#default_value' => $data['under'],
      '#description' => t('If <em>not</em> set, this will create a solid flat layer, probably totally obscuring the source image'),
    ),
  );
  $form['info'] = array('#value' => t('Enter values in ONLY ONE of the below options. Either exact or relative. Most values are optional - you can adjust only one dimension as needed. If no useful values are set, the current base image size will be used.'));
  $form['exact'] = array(
    '#type' => 'fieldset',
    '#collapsible' => TRUE,
    '#title' => 'Exact size',
    'help' => array(
      '#type' => 'markup',
      '#value' => t('Set the canvas to a precise size, possibly cropping the image. Use to start with a known size.'),
      '#prefix' => '<p>',
      '#suffix' => '</p>',
    ),
    'width' => array(
      '#type' => 'textfield',
      '#title' => t('Width'),
      '#default_value' => $data['exact']['width'],
      '#description' => t('Enter a value in pixels or percent'),
      '#size' => 5,
    ),
    'height' => array(
      '#type' => 'textfield',
      '#title' => t('Height'),
      '#default_value' => $data['exact']['height'],
      '#description' => t('Enter a value in pixels or percent'),
      '#size' => 5,
    ),
  );
  $form['exact'] = array_merge($form['exact'], imagecache_actions_pos_form($data['exact']));
  if (! $data['exact']['width'] && !$data['exact']['height']) {
    $form['exact']['#collapsed'] = TRUE;
  }

  $form['relative'] = array(
    '#type' => 'fieldset',
    '#collapsible' => TRUE,
    '#title' => t('Relative size'),
    'help' => array(
      '#type' => 'markup',
      '#value' => '<p>' . t('Set the canvas to a relative size, based on the current image dimensions. Use to add simple borders or expand by a fixed amount. Negative values may crop the image.') . '</p>',
    ),
    'leftdiff' => array(
      '#type' => 'textfield',
      '#title' => t('left difference'),
      '#default_value' => $data['relative']['leftdiff'],
      '#size' => 6,
      '#description' => t('Enter an offset in pixels.'),
    ),
    'rightdiff' => array(
      '#type' => 'textfield',
      '#title' => t('right difference'),
      '#default_value' => $data['relative']['rightdiff'],
      '#size' => 6,
      '#description' => t('Enter an offset in pixels.'),
    ),
    'topdiff' => array(
      '#type' => 'textfield',
      '#title' => t('top difference'),
      '#default_value' => $data['relative']['topdiff'],
      '#size' => 6,
      '#description' => t('Enter an offset in pixels.'),
    ),
    'bottomdiff' => array(
      '#type' => 'textfield',
      '#title' => t('bottom difference'),
      '#default_value' => $data['relative']['bottomdiff'],
      '#size' => 6,
      '#description' => t('Enter an offset in pixels.'),
    ),
  );
  if (! $data['relative']['leftdiff'] && !$data['relative']['rightdiff'] && !$data['relative']['topdiff'] && !$data['relative']['bottomdiff']) {
    $form['relative']['#collapsed'] = TRUE;
  }

  $form['#submit'][] = 'canvasactions_definecanvas_form_submit';
  return $form;
}

/**
 * Implementation of theme_hook() for imagecache_ui.module
 */
function theme_canvasactions_definecanvas_summary($variables) {
  $data = $variables['data'];
  if ($data['exact']['width'] || $data['exact']['height']) {
    $w = !empty($data['exact']['width']) ? $data['exact']['width'] : '100%';
    $h = !empty($data['exact']['height']) ? $data['exact']['height'] : '100%';
    $x = !empty($data['exact']['xpos']) ? $data['exact']['xpos'] : '0';
    $y = !empty($data['exact']['ypos']) ? $data['exact']['ypos'] : '0';
    $output = "{$w}x{$h} ($x, $y)";
  }
  else {
    $output = ' left:' . $data['relative']['leftdiff'];
    $output .= ' right:' . $data['relative']['rightdiff'];
    $output .= ' top:' . $data['relative']['topdiff'];
    $output .= ' bottom:' . $data['relative']['bottomdiff'];
  }
  $output .= theme('imagecacheactions_rgb', array('RGB' => $data['RGB']));
  $output .= ($data['under']) ? t(" <b>under</b> image ") : t(" <b>over</b> image ");
  return $output;
}

/**
 * Implementation of hook_image()
 *
 * Creates a solid background canvas
 *
 * Process the imagecache action on the passed image
 *
 * @param $image
 * array defining an image file, including  :
 *
 *   $image- >source as the filename,
 *
 *   $image->info array
 *
 *   $image->resource handle on the image object
 */
function canvasactions_definecanvas_effect($image, $data) {
  // May be given either exact or relative dimensions.
  if ($data['exact']['width'] || $data['exact']['height']) {
    // Allows only one dimension to be used if the other is unset.
    if (!$data['exact']['width']) {
      $data['exact']['width'] = $image->info['width'];
    }
    if (!$data['exact']['height']) {
      $data['exact']['height'] = $image->info['height'];
    }

    $targetsize['width'] = imagecache_actions_percent_filter($data['exact']['width'], $image->info['width']);
    $targetsize['height'] = imagecache_actions_percent_filter($data['exact']['height'], $image->info['height']);

    $targetsize['left'] = image_filter_keyword($data['exact']['xpos'], $targetsize['width'], $image->info['width']);
    $targetsize['top'] = image_filter_keyword($data['exact']['ypos'], $targetsize['height'], $image->info['height']);

  }
  else {
    // calculate relative size
    $targetsize['width'] = $image->info['width'] + $data['relative']['leftdiff'] + $data['relative']['rightdiff'];
    $targetsize['height'] = $image->info['height'] + $data['relative']['topdiff'] + $data['relative']['bottomdiff'];
    $targetsize['left'] = $data['relative']['leftdiff'];
    $targetsize['top'] = $data['relative']['topdiff'];
  }

  // convert 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);
  }

  // All the maths is done, now defer to the api toolkits;
  $data['targetsize'] = $targetsize;

  $success = image_toolkit_invoke('definecanvas', $image, array($data));
  if ($success) {
    $image->info['width'] = $targetsize['width'];
    $image->info['height'] = $targetsize['height'];
  }
  return $success;
}

function canvasactions_definecanvas_dimensions(array &$dimensions, array $data) {
  // May be given either exact or relative dimensions.
  if ($data['exact']['width'] || $data['exact']['height']) {
    // Allows only one dimension to be used if the other is unset.
    if (!$data['exact']['width']) {
      $data['exact']['width'] = $dimensions['width'];
    }
    if (!$data['exact']['height']) {
      $data['exact']['height'] = $dimensions['height'];
    }

    $dimensions['width'] = imagecache_actions_percent_filter($data['exact']['width'], $dimensions['width']);
    $dimensions['height'] = imagecache_actions_percent_filter($data['exact']['height'], $dimensions['height']);
  }
  else {
    // calculate relative size
    $dimensions['width'] = $dimensions['width'] + $data['relative']['leftdiff'] + $data['relative']['rightdiff'];
    $dimensions['height'] = $dimensions['height'] + $data['relative']['topdiff'] + $data['relative']['bottomdiff'];
  }
}

/**
 * Draw a color (or transparency) behind an image
 *
 * $targetsize is an array expected to contain a width,height and a left,top
 * offset.
 */
function image_gd_definecanvas($image, $data = array()) {
  $targetsize = $data['targetsize'];
  $RGB = $data['RGB'];

  $newcanvas = imagecreatetruecolor($targetsize['width'], $targetsize['height']);
  imagesavealpha($newcanvas, TRUE);
  imagealphablending($newcanvas, FALSE);
  imagesavealpha($image->resource, TRUE);
  if ($RGB['HEX']) {
    // Set color, allow it to define transparency, or assume opaque.
    $background = imagecolorallocatealpha($newcanvas, $RGB['red'], $RGB['green'], $RGB['blue'], $RGB['alpha']);
  }
  else {
    // No color, attempt transparency, assume white
    $background = imagecolorallocatealpha($newcanvas, 255, 255, 255, 127);
  }
  imagefilledrectangle($newcanvas, 0, 0, $targetsize['width'], $targetsize['height'], $background);
  #  imagealphablending($newcanvas, TRUE);

  if ($data['under']) {
    $canvas_object = (object) array(
      'resource' => $newcanvas,
      'info' => array(
        'width' => $targetsize['width'],
        'height' => $targetsize['height'],
        'mime_type' => $image->info['mime_type'],
        'extension' => $image->info['extension'],
      ),
      'toolkit' => $image->toolkit,
    );
    image_overlay($image, $canvas_object, $targetsize['left'], $targetsize['top'], 100, TRUE);
  }
  else {
    $image->resource = $newcanvas;
  }
  return TRUE;
}

/**
 * Draw a color (or transparency) behind an image
 * $targetsize is an array expected to contain a width,height and a left,top
 * offset.
 *
 * See http://www.imagemagick.org/script/command-line-options.php#extent
 * @todo: reset gravity?
 */
function image_imagemagick_definecanvas($image, $data = array()) {
  $backgroundcolor = $data['RGB']['HEX'] != '' ? '#'. $data['RGB']['HEX'] : 'None';
  $image->ops[] = '-background '. escapeshellarg($backgroundcolor);

  $compose_operator = $data['under'] ? 'src-over' : 'dst-over';
  $image->ops[] = "-compose $compose_operator";

  $targetsize = $data['targetsize'];
  $geometry = sprintf('%dx%d', $targetsize['width'], $targetsize['height']);
  if ($targetsize['left'] || $targetsize['top']) {
    $geometry .= sprintf('%+d%+d', -$targetsize['left'], -$targetsize['top']);
  }
  $image->ops[] =  "-extent $geometry";

  return TRUE;
}

////////////////////////////////////////////////

/**
 * Place a given image under the current canvas
 *
 * Implementation of imagecache_hook_form()
 *
 * @param $data array of settings for this action
 * @return a form definition
 */
function canvasactions_canvas2file_form($data) {
//   if (image_get_toolkit() != 'gd') {
//     drupal_set_message('Overlays are not currently supported by using imagemagick. This effect requires GD image toolkit only.', 'warning');
//   }

  $defaults = array(
    'xpos' => '0',
    'ypos' => '0',
    'alpha' => '100',
    'path' => '',
    'dimensions' => 'original',
  );
  $data = array_merge($defaults, (array) $data);

  $form = imagecache_actions_pos_form($data);
  $form['alpha'] = array(
    '#type' => 'textfield',
    '#title' => t('opacity'),
    '#default_value' => $data['alpha'],
    '#size' => 6,
    '#description' => t('Opacity: 0-100. Be aware that values other than 100% may be slow to process.'),
  );
  $form['path'] = array(
    '#type' => 'textfield',
    '#title' => t('file name'),
    '#default_value' => $data['path'],
    '#description' => imagecache_actions_file_field_description(),
    '#element_validate' => array('imagecache_actions_validate_file'),
  );
  $form['dimensions'] = array(
    '#type' => 'radios',
    '#title' => t('final dimensions'),
    '#default_value' => $data['dimensions'],
    '#options' => array(
      'original' => 'original (dimensions are retained)',
      'background' => 'background (image will be forced to match the size of the background)',
      'minimum' => 'minimum (image may be cropped)',
      'maximum' => 'maximum (image may end up with gaps)',
    ),
    '#description' => t('What to do when the background image is a different size from the source image. Backgrounds are not tiled, but may be arbitrarily large.'),
  );
  return $form;
}

/**
 * Implementation of theme_hook() for imagecache_ui.module
 */
function theme_canvasactions_canvas2file_summary($variables) {
  $data = $variables['data'];
  $file = $data['path'];
  return "xpos:{$data['xpos']} , ypos:{$data['ypos']} alpha:{$data['alpha']}%. file: $file, dimensions:{$data['dimensions']}";
}

/**
 * Place the source image on the current background
 *
 * Implementation of hook_image()
 *
 * Note - this is currently incompatable with imagemagick, due to the way it
 * addresses $image->resource directly - a gd only thing.
 *
 * @param $image
 * @param $data
 */
function canvasactions_canvas2file_image(&$image, $data = array()) {
  $underlay = imagecache_actions_image_load($data['path'], $image->toolkit);
  if ($underlay) {
    // To handle odd sizes, we will resize/crop the background image to the
    // desired dimensions before starting the merge. The built-in
    // imagecopymerge, and the watermark library both do not allow overlays to
    // be bigger than the target.

    // Adjust size
    $crop_rules = array(
      'xoffset' => 0,
      'yoffset' => 0,
    );
    if (empty($data['dimensions'])) {
      $data['dimensions'] = 'original';
    }
    switch ($data['dimensions']) {
      case 'original':
        // If the underlay is smaller than the target size,
        // then when preparing the underlay by cropping it,
        // the offsets may need to be negative
        // which will produce a 'cropped' image larger than the original.
        // In this case, we need to calculate the position of the bg image
        // in relation to the space it will occupy under the top layer
        #$crop_rules['xoffset'] = $underlay->info['width'] - $image->info['width'] ;

        $crop_rules['width'] = $image->info['width'];
        $crop_rules['height']  = $image->info['height'];
        break;
      case 'background':
        $crop_rules['width'] = $underlay->info['width'];
        $crop_rules['height'] = $underlay->info['height'];
        break;
      case 'minimum':
        $crop_rules['width'] = min($underlay->info['width'], $image->info['width']);
        $crop_rules['height'] = min($underlay->info['height'], $image->info['height']);
        break;
      case 'maximum':
        $crop_rules['width'] = max($underlay->info['width'], $image->info['width']);
        $crop_rules['height'] = max($underlay->info['height'], $image->info['height']);
        break;
    }
    // imageapi crop assumes upsize is legal.

    // Crop both before processing to avoid unwanted processing.
    image_crop_effect($underlay, $crop_rules);
    # BUG - this doesn't position either
    // Actually this fails because imagecache_crop fills it with solid color when 'cropping' to a larger size.
    #imagecache_crop_image($image, $crop_rules);
    #dpm(get_defined_vars());
    // This func modifies the underlay image by ref, placing the current canvas on it
    if (image_overlay($image, $underlay, $data['xpos'], $data['ypos'], $data['alpha'], TRUE)) {
      #$image->resource = $underlay->resource;
      $image = $underlay;
      return TRUE;
    }
  }
  return FALSE;
}

/**
 * Image dimensions callback; canvas2file (underlay/background).
 *
 * @param array $dimensions
 *   Dimensions to be modified - an associative array containing the items
 *   'width' and 'height' (in pixels).
 * @param $data
 *   An associative array containing the effect data.
 */
function canvasactions_canvas2file_dimensions(array &$dimensions, array $data) {
  if ($data['dimensions'] !== 'original') {
    $underlay = imagecache_actions_image_load($data['path']);
    if ($underlay) {
      switch ($data['dimensions']) {
        case 'background':
          $dimensions['width'] = $underlay->info['width'];
          $dimensions['height'] = $underlay->info['height'];
          break;
        case 'minimum':
          $dimensions['width'] = min($underlay->info['width'], $dimensions['width']);
          $dimensions['height'] = min($underlay->info['height'], $dimensions['height']);
          break;
        case 'maximum':
          $dimensions['width'] = max($underlay->info['width'], $dimensions['width']);
          $dimensions['height'] = max($underlay->info['height'], $dimensions['height']);
          break;
      }
    }
  }
}

/**
 * Place a given image on top of the current canvas
 *
 * Implementation of imagecache_hook_form()
 *
 * @param $data array of settings for this action
 * @return a form definition
 */
function canvasactions_file2canvas_form($data) {

  $defaults = array(
    'xpos' => '',
    'ypos' => '',
    'alpha' => '100',
    'path' => '',
  );
  $data = array_merge($defaults, (array) $data);

  $form = array(
    'help' => array(
      '#type' => 'markup',
      '#value' => t('Note that using a transparent overlay that is larger than the source image may result in unwanted results - a solid background.'),
    ),
  );
  $form += imagecache_actions_pos_form($data);
  $form['alpha'] = array(
    '#type' => 'textfield',
    '#title' => t('opacity'),
    '#default_value' => $data['alpha'],
    '#size' => 6,
    '#description' => t('Opacity: 0-100. <b>Warning:</b> Due to a limitation in the GD toolkit, using an opacity other than 100% requires the system to use an algorithm that\'s much slower than the built-in functions. If you want partial transparency, you are better to use an already-transparent png as the overlay source image.'),
  );
  $form['path'] = array(
    '#type' => 'textfield',
    '#title' => t('file name'),
    '#default_value' => $data['path'],
    '#description' => imagecache_actions_file_field_description(),
    '#element_validate' => array('imagecache_actions_validate_file'),
  );
  return $form;
}

/**
 * Implementation of theme_hook() for imagecache_ui.module
 */
function theme_canvasactions_file2canvas_summary($variables) {
  $data = $variables['data'];
  return '<strong>' . $data['path'] . '</strong> x:' . $data['xpos'] . ', y:' . $data['ypos'] . ' alpha:' . (@$data['alpha'] ? $data['alpha'] : 100) . '%';
}

/**
 * Place the source image on the current background
 *
 * Implementation of hook_image()
 *
 *
 * @param $image
 * @param $data
 */
function canvasactions_file2canvas_image($image, $data = array()) {
  $overlay = imagecache_actions_image_load($data['path']);
  if ($overlay) {
    if (!isset($data['alpha']) ) {
      $data['alpha'] = 100;
    }
    return image_overlay($image, $overlay, $data['xpos'], $data['ypos'], $data['alpha']);
  }
  return FALSE;
}

///////////////////////////////////////////////////////////////////

/**
 * Place the source image on top of the current canvas
 *
 * Implementation of imagecache_hook_form()
 *
 *
 *
 * @param $data array of settings for this action
 * @return a form definition
 */
function canvasactions_source2canvas_form($data) {
  $defaults = array(
    'xpos' => '',
    'ypos' => '',
    'alpha' => '100',
    'path' => '',
  );
  $data = array_merge($defaults, (array) $data);

  $form = imagecache_actions_pos_form($data);
  $form['alpha'] = array(
    '#type' => 'textfield',
    '#title' => t('opacity'),
    '#default_value' => $data['alpha'],
    '#size' => 6,
    '#description' => t('Opacity: 0-100.'),
  );
  return $form;
}


/**
 * Implementation of theme_hook() for imagecache_ui.module
 */
function theme_canvasactions_source2canvas_summary($variables) {
  $data = $variables['data'];
  return 'xpos:' . $data['xpos'] . ', ypos:' . $data['ypos'] . ' alpha:' . $data['alpha'] . '%';
}

/**
 * Place the source image on the current background
 *
 * Implementation of hook_image()
 *
 *
 * @param $image
 * @param $data
 */
function canvasactions_source2canvas_image($image, $data = array()) {
  $overlay = image_load($image->source, $image->toolkit);
  return image_overlay($image, $overlay, $data['xpos'], $data['ypos'], $data['alpha']);
}

/**
 * Switch between presets depending on logic
 *
 * Implementation of imagecache_hook_form()
 *
 * @param $data array of settings for this action
 * @return a form definition
 */
function canvasactions_aspect_form($data) {
  $defaults = array(
    'ratio_adjustment' => 1,
    'portrait' => NULL,
    'landscape' => NULL,
  );
  $data = array_merge($defaults, (array)$data);

  $form = array(
    'help' => array(
      '#type' => 'markup',
      '#value' => t('You must create the two presets to use <em>before</em> enabling this process.'),
    )
  );

  $styles = image_style_options(TRUE);

  $form['portrait'] = array(
    '#type' => 'select',
    '#title' => t('Style to use if the image is portrait (vertical)'),
    '#default_value' => $data['portrait'],
    '#options' => $styles,
  );
  $form['landscape'] = array(
    '#type' => 'select',
    '#title' => t('Style to use if the image is landscape (horizontal)'),
    '#default_value' => $data['landscape'],
    '#options' => $styles,
  );

  $form['ratio_adjustment'] = array(
    '#type' => 'textfield',
    '#title' => t('Ratio Adjustment (advanced)'),
    '#size' => 3,
    '#default_value' => $data['ratio_adjustment'],
    '#description' => t("
This allows you to bend the rules for how different the proportions need to be to trigger the switch.
<br/>If the (width/height)*n is greater than 1, use 'landscape', otherwise use 'portrait'.
<br/>When n = 1 (the default) it will switch between portrait and landscape modes.
<br/>If n > 1, images that are slightly wide will still be treated as portraits.
If n < 1 then blunt portraits will be treated as landscape.
    "),
  );


  return $form;
}


/**
 * Implementation of theme_hook() for imagecache_ui.module
 */
function theme_canvasactions_aspect_summary($variables) {
  $data = $variables['data'];
  $ratio_adjustment = '';
  if ($data['ratio_adjustment'] != 1) {
    $ratio_adjustment = " (switch at 1:{$data['ratio_adjustment']})";
  }
  return 'Portrait size: <strong>'. $data['portrait'] . '</strong>. Landscape size: <strong>'. $data['landscape'] .'</strong>'. $ratio_adjustment ;
}

/**
 * Choose the action and trigger that.
 *
 * Implementation of hook_image()
 *
 * @param $image
 * @param $data
 */
function canvasactions_aspect_image($image, $data = array()) {
  $ratio_adjustment = 0 + $data['ratio_adjustment'];
  if (!$ratio_adjustment) {
    $ratio_adjustment = 1;
  }
  $aspect = $image->info['width'] / $image->info['height'];
  // width / height * adjustment. If > 1, it's wide.
  $style_name = (($aspect * $ratio_adjustment) > 1) ? $data['landscape'] : $data['portrait'];
  $style = image_style_load($style_name);

  if (empty($style_name)) {
    // Required preset has gone missing?
    watchdog('imagecache_canvasactions', "When running 'aspect' action, I was unable to load sub-action %style_name. Either it's been deleted or the DB needs an update", array('%style_name' => $style_name), WATCHDOG_ERROR);
    return FALSE;
  }

  // Run the preset actions ourself.
  // Cannot invoke a preset from the top as it handles filenames, not image objects.
  // Ripped from imagecache_build_derivative()
  foreach ($style['effects'] as $sub_effect) {

    // These actions really should interpret the parameters themselves.
    foreach (array('height', 'width') as $param) {
     if (isset($sub_effect['data'][$param])) {
       $sub_effect['data'][$param] = imagecache_actions_percent_filter($sub_effect['data'][$param], $image->info[$param]);
      }
    }

    foreach (array(
      'xoffset' => 'width',
      'yoffset' => 'height',
    ) as $param => $direction) {
      if (isset($sub_effect['data'][$param])) {
        $sub_effect['data'][$param] = image_filter_keyword($sub_effect['data'][$param], $image->info[$direction], $sub_effect['data'][$direction]);
      }
    }

    image_effect_apply($image, $sub_effect);
  }
  return TRUE;
}

/**
 * Image dimensions callback; Aspect.
 *
 * @param array $dimensions
 *   Dimensions to be modified - an associative array containing the items
 *   'width' and 'height' (in pixels).
 * @param $data
 *   An associative array containing the effect data.
 */
function canvasactions_aspect_dimensions(array &$dimensions, array $data) {
  // @todo: use callbacks or passthrough setting from the styles themselves?
  $dimensions['width'] = NULL;
  $dimensions['height'] = NULL;
}