Counting Blocks in Drupal

We had a situation where we had a region of blocks, but the number of those blocks could fluctuate. This was based on how much content the client wanted to feature in the region.

This posed a problem when it came to the layout CSS – using traditional floats, we need to know how many things we have that we’re trying to lay out. This lets us know how wide to set the child elements. Flexbox would have solved a lot of this, but alas.

So we needed some way to know how many blocks would be present in a region, even if that number changed. We could adjust the CSS accordingly.

It turned out to be a really simple preprocess function:

function THEMENAME_preprocess_region(&$vars) {
		$block_number = count($vars['elements']) - 5;
 		$vars['classes_array'][''] = 'block-count--' . $block_number;
	}

This function needs to go in your theme’s template.php file, and be sure to change ‘THEMENAME’ to whatever your theme is, well, named.

What is that ‘5’ all about? In Drupal, a region contains a number of arrays, and the blocks show up in the ‘elements’ array. That array lists all of the blocks, plus 5 other properties of the region. So we count the number of items in the elements array, subtract by 5, and that is the number of blocks we have.

This will attach a class to the region parent that indicates the number of blocks, e.g. ‘block-count–4’ or ‘block-count–2’.

This works on any region that has a <div> wrapped around its output. So, the $content region usually won’t get this class. Most other regions should.

With that, you can do things like this in your CSS:

.block {
	float: left;
}
.block-count--2 .block {
	width: 50%;
}
.block-count--3 .block {
	width: 33%;
}
.block-count--4 .block {
	width: 25%;
}

I hope you find this helpful!