I am inspecting a wordpress theme code and I found this row of code:
840 <= $width && $sizes = '(max-width: 709px) 85vw, (max-width: 909px) 67vw, (max-width: 1362px) 62vw, 840px';
What does this row mean in terms of php?
To be more clear, this is the whole function:
/**
* Add custom image sizes attribute to enhance responsive image functionality
* for content images
*
* @since Twenty Sixteen 1.0
*
* @param string $sizes A source size value for use in a 'sizes' attribute.
* @param array $size Image size. Accepts an array of width and height
* values in pixels (in that order).
* @return string A source size value for use in a content image 'sizes' attribute.
*/
function twentysixteen_content_image_sizes_attr( $sizes, $size ) {
$width = $size[0];
840 <= $width && $sizes = '(max-width: 709px) 85vw, (max-width: 909px) 67vw, (max-width: 1362px) 62vw, 840px';
if ( 'page' === get_post_type() ) {
840 > $width && $sizes = '(max-width: ' . $width . 'px) 85vw, ' . $width . 'px';
} else {
840 > $width && 600 <= $width && $sizes = '(max-width: 709px) 85vw, (max-width: 909px) 67vw, (max-width: 984px) 61vw, (max-width: 1362px) 45vw, 600px';
600 > $width && $sizes = '(max-width: ' . $width . 'px) 85vw, ' . $width . 'px';
}
return $sizes;
}