Yes, very possible, and I do exactly the same for a client site.
First I created a new attribute for categories, to allow me to set that a category needs to use the normal link. This is done via a module.
The module structure:
app/code/local/ProxiBlue/AttributeUseNormalFilterLink/
app/code/local/ProxiBlue/AttributeUseNormalFilterLink/Model/Mysql4/
app/code/local/ProxiBlue/AttributeUseNormalFilterLink/etc
app/code/local/ProxiBlue/AttributeUseNormalFilterLink/sql/proxiblue_filterlink_setup
In Model/Mysql4 I have file Setup.php
Contents:
class ProxiBlue_AttributeUseNormalFilterLink_Model_Mysql4_Setup extends Mage_Catalog_Model_Resource_Setup {
private $_category_attributes = array(
'use_normal_filter_link' => array(
'label' => 'Use normal filter link in left navigation',
'type' => 'int',
'input' => 'select',
'source' => 'eav/entity_attribute_source_boolean',
'default' => '0',
'global' => Mage_Catalog_Model_Resource_Eav_Attribute::SCOPE_STORE,
'visible' => true,
'required' => false,
'user_defined' => false,
'visible_on_front' => true,
'is_visible_on_front' =>true,
'used_in_product_listing' => true,
)
);
public function getDefaultEntities() {
$entities = array();
$default_attribute_options = array(
'group' => 'General Information',
'required' => false,
);
/* Build Catalog Attributes */
$entities['catalog_category'] = array(
'entity_model' => 'catalog/category',
'attribute_model' => 'catalog/resource_eav_attribute',
'table' => 'catalog/category',
'additional_attribute_table' => 'catalog/eav_attribute',
'entity_attribute_collection' => 'catalog/category_attribute_collection',
'attributes' => array(),
);
foreach ($this->_category_attributes as $name => $options) {
/* Override values provided by the defaults */
$attribute_options = $default_attribute_options;
foreach ($options as $k => $v) {
$attribute_options[$k] = $v;
}
$entities['catalog_category']['attributes'][$name] = $attribute_options;
}
return $entities;
}
}
in etc folder I have the config.xml
contents:
<modules>
<ProxiBlue_AttributeUseNormalFilterLink>
<version>0.0.1</version>
</ProxiBlue_AttributeUseNormalFilterLink>
</modules>
<global>
<models>
<proxiblue_attributeusenormalfilterlink>
<class>ProxiBlue_AttributeUseNormalFilterLink_Model</class>
</proxiblue_attributeusenormalfilterlink>
</models>
<resources>
<proxiblue_filterlink_setup>
<setup>
<module>ProxiBlue_AttributeUseNormalFilterLink</module>
<class>ProxiBlue_AttributeUseNormalFilterLink_Model_Mysql4_Setup</class>
</setup>
</proxiblue_filterlink_setup>
</resources>
</global>
and in the sql fiolder I have the install script : mysql4-install-0.0.1.php
contents:
$installer = $this;
$installer->startSetup();
$installer->installEntities();
$installer->endSetup();
Now you can adjust the filter template to use this attribute, and any category can be set to display the actual category link, and not work as a filter.
Copy the template catalog/layer/filter.phtml to your custtom theme folder, then adjust as follows: (note this has some other customization, so pull the bits you need)
<?php $category = false; ?>
<?php if ($this instanceof Mage_Catalog_Block_Layer_Filter_Category): ?>
<?php $category = Mage::registry('current_category'); ?>
<?php if ($category): ?>
<h2>
<a class='level-top' href="<?php $category->getUrl(); ?>"><?php echo $category->getName(); ?></a>
</h2>
<?php endif; ?>
<?php endif; ?>
<ol>
<?php foreach ($this->getItems() as $_item): ?>
<li>
<?php if ($_item->getCount() > 0): ?>
<?php
$link = $_item->getUrl();
if(is_object($category) && !$category->getUseNormalFilterLink()){
$filter = $_item->getFilter();
if($filter instanceof Mage_Catalog_Model_Layer_Filter_Category) {
$linkCategory = mage::getModel('catalog/category')->load($_item->getValue());
if($linkCategory->getId()){
$link = $linkCategory->getUrl();
}
}
}
?>
<a href="<?php echo $this->urlEscape($link) ?>"><?php echo $_item->getLabel() ?></a>
<?php else: echo $_item->getLabel() ?>
<?php endif; ?>
<?php //echo $_item->getCount() ?>
</li>
<?php endforeach ?>
</ol>
Best Answer
The layered nav options are displayed using the template
app/design/frontend/{package}/{theme}/template/catalog/layer/filter.phtml.If you want you can add your logic in there.
But I don't recommend this approach. Doing it like this 10 of your brands (or other filter) will always get more visibility than the rest of them. I'm no SEO specialist but I think that having hidden links will affect your page rank (Can someone confirm or bust this?).
I suggest having a
max-heighton each filter type with an overflow scroll.