getkirby tags/figure.php with srcset and thumbnail creation

figure.php

<?php

kirbytext::$tags['figure'] = array(
  'attr' => array(
    'width',
    'height',
    'alt',
    'text',
    'title',
    'class',
    'imgclass',
    'linkclass',
    'caption',
    'link',
    'target',
    'popup',
    'rel'
  ),
  'html' => function($tag) {
    $url     = $tag->attr('figure');
    $alt     = $tag->attr('alt');
    $title   = $tag->attr('title');
    $link    = $tag->attr('link');
    $caption = $tag->attr('caption');
    $file    = $tag->file($url);
    // use the file url if available and otherwise the given url
    $url = $file ? $file->url() : url($url);

    // thumbs
    $width = $tag->attr('width') ? $tag->attr('width') : '800';
    $url = thumb($file, array('width' => $width, 'crop' => false, 'quality' => 85))->url();
    $url2x = thumb($file, array('width' => $width*2, 'crop' => false, 'quality' => 85))->url();
    $url3x = thumb($file, array('width' => $width*3, 'crop' => false, 'quality' => 85))->url();
    
    // srcset images
    $img = explode('.', basename($url));
    $path = dirname($url). '/';
    $srcset  = $url   . ' 1x' . ', ';
    $srcset .= $url2x . ' 2x' . ', ';
    $srcset .= $url3x . ' 3x';

    // alt is just an alternative for text
    if($text = $tag->attr('text')) $alt = $text;
    // try to get the title from the image object and use it as alt text
    if($file) {
      if(empty($alt) and $file->alt() != '') {
        $alt = $file->alt();
      }
      if(empty($title) and $file->title() != '') {
        $title = $file->title();
      }
    }
    if(empty($alt)) $alt = pathinfo($url, PATHINFO_FILENAME);
    $image = html::img($url, array(
      'srcset' => html($srcset),
      'width'  => $tag->attr('width'),
      'height' => thumb($file, array('width' => $width, 'crop' => false, 'quality' => 85))->height(),
      'class'  => $tag->attr('imgclass'),
      'title'  => html($title),
      'alt'    => html($alt)
    ));
    if($tag->attr('link')) {
      // build the href for the link
      if($link == 'self') {
        $href = $url;
      } else if($file and $link == $file->filename()) {
        $href = $file->url();
      } else {
        $href = $link;
      }
      $image = html::a(url($href), $image, array(
      'rel'    => $tag->attr('rel'),
      'class'  => $tag->attr('linkclass'),
      'title'  => html($tag->attr('title')),
      'target' => $tag->target()
      ));
    }
    $figure = new Brick('figure');
    $figure->addClass($tag->attr('class'));
    $figure->append($image);
    if(!empty($caption)) {
      $figure->append('<figcaption>' . html($caption) . '</figcaption>');
    }
    return $figure;
  }
);

?>