Leveraging field_get_items variable in a custom field template

Question

I can use a template preprocess function for node to simply get the alt tag of an image field image using the venerable field_get_items as such:

function MYTHEME_preprocess_node(&$vars, $hook) {
// Global node.
  $node = $vars['node'];

 $field_image_items = field_get_items('node', $node, 'field_image');
  // Load individual data from 'field_image'.
    $vars['alt_caption'] = $field_image_items[0]['alt'];
}

Then in node.tpl.php, I can render the alt tag of the image from the variable we created above as:

<?php print $alt_caption; ?>

... and that works great.

However, I'd like to customize the template for the image itself so when I create a field--field_image.tpl.php template, sure enough the image renders fine but if I add the $alt_caption variable, that does not render. I'm guessing this will simply not work or there is an extra step I need to do for the variable to render in this new template.

Answer 1

You need TEMPLATE_preprocess_field() function at template.php

You can use this preprocess function in same way as you are doing for NODE. Like -

function MYTHEME_preprocess_field(&$vars) {
  if ($node = menu_get_object()){
    $node = $vars['node'];
    $field_image_items = field_get_items('node', $node, 'field_image');
    $vars['alt_caption'] = $field_image_items[0]['alt'];
  }
}

Then go to your TPL made for your particular field and print it where ever you like just like you have mentioned --

<?php print $alt_caption; ?>

And it will work like charm!! I have implemented like this several times.

But yeah...don't forget to clear your cache after this implementation.

Answer 2

As I was having issues with this working in teaser mode, another way to do this is to forgo the preprocess function altogether and render this in your custom image field template using the #item var that's already available:

 <?php if ($item['#item']['alt']): ?>
    <figcaption><?php print $item['#item']['alt']; ?></figcaption>
 <?php endif; ?>

This will render a nice HTML5 caption under the image based on your alt tag. What's interesting about this is that the default field.tpl.php template in D7 does not give item as a possible variable. Inspiration for this method here.