WIP Implement viewhelper for image lazyloading

2021-12-26 21:09:22 +01:00
parent f9e2fc888d
commit 3cdd02ed21
6 changed files with 83 additions and 32 deletions
@@ -0,0 +1,47 @@
+<?php
+
+namespace EP\EpTheme\ViewHelpers;
+
+use TYPO3\CMS\Core\Utility\GeneralUtility;
+use TYPO3\CMS\Fluid\ViewHelpers\ImageViewHelper;
+
+class LazyLoadImageViewHelper extends ImageViewHelper
+{
+    public function initializeArguments()
+    {
+        parent::initializeArguments();
+        $this->registerArgument('loaderimg', 'string', '', false);
+    }
+
+    public function render(): string
+    {
+        parent::render();
+
+        $src = $this->tag->getAttribute('src');
+        $this->tag->removeAttribute('src');
+        $this->tag->addAttribute('data', ['src' => $src]);
+
+        if (isset($this->arguments['loaderimg'])) {
+            $loaderImage = $this->imageService->getImage($this->arguments['loaderimg'], null, false);
+            $processingInstructions = [
+                'width' => $this->arguments['width'],
+                'height' => $this->arguments['height'],
+                'minWidth' => $this->arguments['minWidth'],
+                'minHeight' => $this->arguments['minHeight'],
+                'maxWidth' => $this->arguments['maxWidth'],
+                'maxHeight' => $this->arguments['maxHeight'],
+            ];
+            $processedLoaderImage = $this->imageService->applyProcessingInstructions($loaderImage, $processingInstructions);
+            $loaderImageUri = $this->imageService->getImageUri($processedLoaderImage, $this->arguments['absolute']);
+            $this->tag->addAttribute('src', $loaderImageUri);
+        }
+
+        $classes = $this->tag->getAttribute('class');
+        $classItems = GeneralUtility::trimExplode(' ', $classes, true);
+        $classItems[] = 'lazyload';
+        $classes = implode(' ', array_unique($classItems));
+        $this->tag->addAttribute('class', $classes);
+
+        return $this->tag->render();
+    }
+}