retina_images.module in Retina Images 8

This module provides an image effect to assist in outputing high resolution images.

File

retina_images.module

<?php

/**
 * @file
 * This module provides an image effect to assist in outputing high resolution images.
 */
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Url;

/**
 * Implements hook_image_effect_info_alter().
 */
function retina_images_image_effect_info_alter(&$effects) {
  $effects['image_resize']['class'] = 'Drupal\\retina_images\\Plugin\\ImageEffect\\RetinaResizeImageEffect';
  $effects['image_scale']['class'] = 'Drupal\\retina_images\\Plugin\\ImageEffect\\RetinaScaleImageEffect';
  $effects['image_scale_and_crop']['class'] = 'Drupal\\retina_images\\Plugin\\ImageEffect\\RetinaScaleAndCropImageEffect';
  $effects['image_crop']['class'] = 'Drupal\\retina_images\\Plugin\\ImageEffect\\RetinaCropImageEffect';
}

/**
 * Implements hook_theme().
 */
function retina_images_theme() {
  return array(
    'retina_images_image_crop_summary' => array(
      'variables' => array(
        'data' => NULL,
        'effect' => array(),
      ),
    ),
    'retina_images_image_resize_summary' => array(
      'variables' => array(
        'data' => NULL,
        'effect' => array(),
      ),
    ),
    'retina_images_image_scale_summary' => array(
      'variables' => array(
        'data' => NULL,
        'effect' => array(),
      ),
    ),
    'retina_images_image_style_preview' => array(
      'variables' => array(
        'style' => NULL,
      ),
    ),
  );
}

/**
 * Implements hook_form_FORM_ID_alter().
 */
function retina_images_form_image_style_form_alter(&$form, FormStateInterface $form_state) {

  // Get the style to pass to our new theme function.
  $style = $form_state
    ->getFormObject()
    ->getEntity();

  // Don't show the preview on the add form.
  if (isset($form['preview'])) {

    // Override the preview image area to use our own preview.
    // Show the thumbnail preview.
    $preview_arguments = array(
      '#theme' => 'retina_images_image_style_preview',
      '#style' => $style,
    );
    $form['preview'] = array(
      '#type' => 'item',
      '#title' => \Drupal::translation()
        ->translate('Preview'),
      '#markup' => drupal_render($preview_arguments),
      // Render preview above parent elements.
      '#weight' => -5,
    );
  }
}

/**
 * Prepares variables for retina image style preview templates.
 *
 * Default template: retina-images-image-style-preview.html.twig.
 *
 * @param array $variables
 *   An associative array containing:
 *   - style: \Drupal\image\ImageStyleInterface image style being previewed.
 */
function template_preprocess_retina_images_image_style_preview(&$variables) {

  // Style information.
  $style = $variables['style'];
  $variables['style_id'] = $style
    ->id();
  $variables['style_name'] = $style
    ->label();

  // Cache bypass token.
  $variables['cache_bypass'] = REQUEST_TIME;

  // Sample image info.
  $sample_width = 160;
  $sample_height = 160;
  $image_factory = \Drupal::service('image.factory');

  // Set up original file information.
  $original_path = \Drupal::config('image.settings')
    ->get('preview_image');
  $original_image = $image_factory
    ->get($original_path);
  $variables['original'] = array(
    'url' => file_url_transform_relative(file_create_url($original_path)),
    'width' => $original_image
      ->getWidth(),
    'height' => $original_image
      ->getHeight(),
  );
  if ($variables['original']['width'] > $variables['original']['height']) {
    $variables['preview']['original']['width'] = min($variables['original']['width'], $sample_width);
    $variables['preview']['original']['height'] = round($variables['preview']['original']['width'] / $variables['original']['width'] * $variables['original']['height']);
  }
  else {
    $variables['preview']['original']['height'] = min($variables['original']['height'], $sample_height);
    $variables['preview']['original']['width'] = round($variables['preview']['original']['height'] / $variables['original']['height'] * $variables['original']['width']);
  }

  // Set up derivative file information.
  $preview_file = $style
    ->buildUri($original_path);
  $variables['preview_link'] = Url::fromRoute('retina_images.image.style_preview', [
    'image_style' => $style
      ->id(),
  ]);

  // Create derivative if necessary.
  if (!file_exists($preview_file)) {
    $style
      ->createDerivative($original_path, $preview_file);
  }
  $preview_image = $image_factory
    ->get($preview_file);
  $variables['derivative'] = array(
    'url' => file_url_transform_relative(file_create_url($preview_file)),
    'width' => $preview_image
      ->getWidth(),
    'height' => $preview_image
      ->getHeight(),
  );
  $style
    ->transformDimensions($variables['derivative'], $preview_file);
  if ($variables['derivative']['width'] > $variables['derivative']['height']) {
    $variables['preview']['derivative']['width'] = min($variables['derivative']['width'], $sample_width);
    $variables['preview']['derivative']['height'] = round($variables['preview']['derivative']['width'] / $variables['derivative']['width'] * $variables['derivative']['height']);
  }
  else {
    $variables['preview']['derivative']['height'] = min($variables['derivative']['height'], $sample_height);
    $variables['preview']['derivative']['width'] = round($variables['preview']['derivative']['height'] / $variables['derivative']['height'] * $variables['derivative']['width']);
  }

  // Build the preview of the original image.
  $variables['original']['rendered'] = array(
    '#theme' => 'image',
    '#uri' => $original_path,
    '#alt' => t('Sample original image'),
    '#title' => '',
    '#attributes' => array(
      'width' => $variables['original']['width'],
      'height' => $variables['original']['height'],
      'style' => 'width: ' . $variables['preview']['original']['width'] . 'px; height: ' . $variables['preview']['original']['height'] . 'px;',
    ),
  );

  // Build the preview of the image style derivative. Timestamps are added
  // to prevent caching of images on the client side.
  $variables['derivative']['rendered'] = array(
    '#theme' => 'image',
    '#uri' => $variables['derivative']['url'] . '?cache_bypass=' . $variables['cache_bypass'],
    '#alt' => t('Sample modified image'),
    '#title' => '',
    '#attributes' => array(
      'width' => $variables['derivative']['width'],
      'height' => $variables['derivative']['height'],
      'style' => 'width: ' . $variables['preview']['derivative']['width'] . 'px; height: ' . $variables['preview']['derivative']['height'] . 'px;',
    ),
  );
}

Functions

Name	Description
retina_images_form_image_style_form_alter	Implements hook_form_FORM_ID_alter().
retina_images_image_effect_info_alter	Implements hook_image_effect_info_alter().
retina_images_theme	Implements hook_theme().
template_preprocess_retina_images_image_style_preview	Prepares variables for retina image style preview templates.