Focus area View Helper

FluidTemplate.html

    <a href="#"
       class="lazyload fullscreen random-gallery"
       id="js-random-image"
       data-random-images="{h:homePageTeaserImages(
            images: object.images,
            breakPointConfiguration: {
                300: '{maxWidth: \'300\', maxHeight: \'300\'}',
                1000: '{maxWidth: \'1000\', maxHeight: \'1000\'}',
                1900: '{maxWidth: \'1900\', maxHeight: \'1900\'}'}
            ) -> f:format.htmlspecialchars()}"
       data-bgset=""
       data-sizes="auto"
    ></a>

TeaserImagesViewHelper.php

<?php
namespace Helhum\SiteDaniel\ViewHelpers;

/*
 * This file is part of the Daniel Pilar website distribution.
 *
 * It is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License, either version 2
 * of the License, or any later version.
 *
 * For the full copyright and license information, please read
 * http://www.gnu.org/licenses/gpl-2.0.html
 *
 */

use TYPO3\CMS\Core\Resource\Exception\ResourceDoesNotExistException;
use TYPO3\CMS\Core\Resource\FileInterface;
use TYPO3\CMS\Core\Resource\FileReference;
use TYPO3\CMS\Core\Utility\MathUtility;
use TYPO3\CMS\Extbase\Persistence\ObjectStorage;
use TYPO3\CMS\Fluid\Core\ViewHelper\AbstractViewHelper;
use TYPO3\CMS\Frontend\Controller\TypoScriptFrontendController;

/**
 * Class HomePageTeaserImagesViewHelper
 */
class HomePageTeaserImagesViewHelper extends AbstractViewHelper
{
    /**
     * @var TypoScriptFrontendController
     */
    protected $typoScriptFrontendController;

    /**
     * @var \TYPO3\CMS\Extbase\Service\ImageService
     */
    protected $imageService;

    /**
     * @param \TYPO3\CMS\Extbase\Service\ImageService $imageService
     */
    public function injectImageService(\TYPO3\CMS\Extbase\Service\ImageService $imageService)
    {
        $this->imageService = $imageService;
    }

    /**
     * HomePageTeaserImagesViewHelper constructor.
     *
     * @param TypoScriptFrontendController|null $typoScriptFrontendController
     */
    public function __construct(TypoScriptFrontendController $typoScriptFrontendController = null)
    {
        $this->typoScriptFrontendController = $typoScriptFrontendController ?: $GLOBALS['TSFE'];
    }

    /**
     * Resizes a given image (if required) and renders the respective img tag
     *
     * @see http://typo3.org/documentation/document-library/references/doc_core_tsref/4.2.0/view/1/5/#id4164427
     * @param \TYPO3\CMS\Extbase\Persistence\ObjectStorage $images
     * @param array $breakPointConfiguration Array of breakpoints and sizes
     * @return string Json.
     * @throws \TYPO3\CMS\Fluid\Core\ViewHelper\Exception
     */
    public function render(ObjectStorage $images = null, array $breakPointConfiguration = array())
    {
        $returnData = array();
        foreach ($this->objectStorageOrNullToArray($images) as $image) {
            try {
                $image = $this->imageService->getImage(null, $image, false);
                $crop = $image instanceof FileReference ? $image->getProperty('crop') : null;
                $imageData = array();
                $imageData['isBright'] = (bool)$image->getProperty('image_is_bright');
                $imageData['backgroundPosition'] = $this->calculateBackgroundPosition($image, $crop);
                foreach ($breakPointConfiguration as $name => $finalProcessingInstructions) {
                    $processedImage = $this->imageService->applyProcessingInstructions($image, $finalProcessingInstructions);
                    $imageData[$name] = $this->imageService->getImageUri($processedImage);
                }
                $imageData['pageURI'] = $this->typoScriptFrontendController->cObj->getTypoLink_URL($image->getProperty('link'));
                $returnData[] = $imageData;
            } catch (ResourceDoesNotExistException $e) {
                // thrown if file does not exist
            } catch (\UnexpectedValueException $e) {
                // thrown if a file has been replaced with a folder
            } catch (\RuntimeException $e) {
                // RuntimeException thrown if a file is outside of a storage
            } catch (\InvalidArgumentException $e) {
                // thrown if file storage does not exist
            }
        }
        return json_encode($returnData, JSON_PRETTY_PRINT|JSON_HEX_AMP|JSON_HEX_APOS|JSON_HEX_QUOT|JSON_HEX_TAG);
    }

    /**
     * @param FileInterface $image
     * @param string $cropDefinition
     * @return string
     */
    protected function calculateBackgroundPosition(FileInterface $image, $cropDefinition)
    {
        if (empty($cropDefinition)) {
            return '50% 50%';
        }
        $cropArea = json_decode($cropDefinition, true);
        $width = $image->getProperty('width');
        $height = $image->getProperty('height');

        $xScale = 100 / $width;
        $yScale = 100 / $height;

        $yAxis = 100 * ($cropArea['y'] + ($cropArea['height'] / 2)) / $height;
        $xAxis = 100 * ((($cropArea['x'] + ($cropArea['width'] / 2)) / $width));

        $cxl = $cropArea['x'];
        $cxr = $width - ($cropArea['x'] + $cropArea['width']);
        $cyt = $cropArea['y'];
        $cyb = $height - ($cropArea['y'] + $cropArea['height']);

        $xAxis += ($cxl - $cxr) * $xScale;
        $yAxis += ($cyt - $cyb) * $yScale;
        $yAxis = MathUtility::forceIntegerInRange($yAxis, 0, 100);
        $xAxis = MathUtility::forceIntegerInRange($xAxis, 0, 100);

        return (int)$xAxis . '% ' . (int)$yAxis . '%';
    }

    /**
     * @param ObjectStorage|null $value
     * @return array
     */
    protected function objectStorageOrNullToArray(ObjectStorage $value = null)
    {
        if ($value === null) {
            return array();
        }
        return $value->toArray();
    }
}