Hi, sorry for the confusion.
When I say “text content”, I mean string.
Your code:
$image_ids = get_field('program_photo_gallery', false, false);
This code appears to be returning an array, not a string. However, the code:
$content = get_field('sidebar_content');
This code returns a string (HTML for the image to be displayed), which is why you can pass it directly to slb_activate(). It is rendered as a thumbnail image in the browser, but it is HTML text (a string) when returned from get_field().
Using apply_filters('the_content',...) is the old manual way of activating links with SLB. So instead of:
echo apply_filters('the_content', $shortcode);
You could simply do:
echo slb_activate($shortcode);
Why does slb_activate() work here? Let’ step through your code:
1. Retrieve image IDs from ACF (result: array value).
$image_ids = get_field('my_custom_gallery_field', false, false);
SLB acts upon links in a string. All we currently have is an array.
2. Build shortcode using image ids (result: string value)
$shortcode = '[gallery ids="' . implode(',', $image_ids) . '"]';
We now have a string value, but it only contains a shortcode, no links for SLB to act upon.
3. Render shortcode into HTML for image gallery (result: string value)
$gallery = do_shortcode( $shortcode );
Now we have the HTML for the gallery including links. We now have links to activate with SLB.
4. Activate links with SLB and output to browser
echo slb_activate($gallery);
Hopefully that makes sense now. The only reason I didn’t spell it out from the beginning is because you were doing such a great job with the code you already had and you were so close! You just needed a nudge in the right direction.
To be clear: The best way to activate non-standard content going forward is using slb_activate(), not apply_filters(). slb_activate() is faster and more efficient.
