ACF Gallery and Backstrech

• gomezvalverde

• June 20, 2016 at 1:53 pm

Hi,
I am trying to make the ACF Gallery be displayed as a full screen background slideshow with jQuery Backstrech http://srobbin.com/jquery-plugins/backstretch/

The script should be something like:

<script>
$.backstretch([
“NYC-001.jpg”,
“NYC-002.jpg”,
“NYC-003.jpg”
], {
duration: 3000,
fade: 750
});
</script>

How can I get the array of gallery images to be inserted into the script?

Thanks!

• James

• June 20, 2016 at 3:53 pm

Hi @gomezvalverde

Please check this thread regarding PHP and Javascript: http://stackoverflow.com/questions/13840429/what-is-the-difference-between-client-side-and-server-side-programming.

Basically, you need to add the PHP code in your JS code. To get the gallery values, please check this page: https://www.advancedcustomfields.com/resources/gallery/.

I hope this helps.

• gomezvalverde

• June 21, 2016 at 1:30 pm

Thanks @James
I am not a programmer and I don’t really understand how this can be done.

The main problem for me is how to get an array of image URLs from the gallery field (it is part of a Options page) and how to make them a variable. I checked how a WP gallery shortcode is done https://www.advancedcustomfields.com/resources/gallery/ but instead of the IDs I need the URL. I also tried using implode to add commas between values, but couldn’t make it work.

Could you please guide me into the right direction to solve this??

My not-working code is below. Thanks!

<!-- trying to get the array of URLs -->
<?php 
$images = get_field('slideshow_gallery', 'option');

if( $images ): 
     foreach( $images as $image ): ?>
		<?php echo $image['url']; ?>,  
		<br>
	<?php endforeach; ?>
<?php endif; ?>
</div>

<!-- Put the URLs inside a div -->
<div id="dom-target" style="display: none;">
    <?php 
        $output = "image01", "image02", "image03";  //just a test
        echo htmlspecialchars($output); /* You have to escape because the result will not be valid HTML otherwise. */
    ?>
</div>

<!-- Put the content into a variable -->
<script>
    var div = document.getElementById("dom-target");
    var myData = div.textContent;
</script>

<script> /* Build backstretch slideshow */
  // Duration is the amount of time in between slides,
  // and fade is value that determines how quickly the next image will fade in
  $.backstretch([
	myData
	
  ], {
	duration: 3000, 
	fade: 750
});
</script>
    

• James

• June 21, 2016 at 1:43 pm

Hi @gomezvalverde

Did the <?php echo $image['url']; ?> code work? I believe you can do it like this:

$.backstretch([
<?php
foreach( $images as $image ) {
    echo '"' . $image['url'] . '",';
}
?>
], {

I hope this helps 🙂

• gomezvalverde

• June 21, 2016 at 2:31 pm

AMAZING!
Thanks a lot, I was becoming crazy trying to make it work.

So I guess I don’t need to use anything extra to get the gallery values into the script, right?
And could it be possible to load different image sizes depending on the device? I guess this is a question for Backstrech forum or Zurb Foundation (I use a theme based on Zurb Foundation)

Anyway, this is the working code in case anyone wants to do something similar
Note: This gallery field is part of a options page, and jQuery Backstrech needs to be enqueued.

<?php  
// Get the ACF gallery images

$images = get_field('slideshow_gallery', 'option');
?>
<script> 
  //Backstretch slideshow
  // Duration is the amount of time in between slides,
  // and fade is value that determines how quickly the next image will fade in

$.backstretch([
<?php
foreach( $images as $image ) {
    echo '"' . $image['url'] . '",';
}
?>
], {
	duration: 3000, 
	fade: 750
});
</script>
    

• James

• June 21, 2016 at 2:45 pm

Hi @gomezvalverde

To get the other sizes of the images, I think you can do it like this:

echo '"' . $image['sizes']['thumbnail'] . '",';

Or:

echo '"' . $image['sizes']['large'] . '",';

If you want to load it depending on the device, I’m afraid you need to ask Backstrech support.

Thanks 🙂

• gomezvalverde

• June 21, 2016 at 10:58 pm

Thanks @James!