Creating tag clouds with Zend\Tag\Cloud

Zend\Tag\Cloud is the rendering part of Zend\Tag. By default it comes with a set of HTML decorators, which allow you to create tag clouds for a website, but also supplies you with two abstract classes to create your own decorators, to create tag clouds in PDF documents for example.

You can instantiate and configure Zend\Tag\Cloud either programmatically or completely via an array or an instance of Traversable. The available options are:

Zend\Tag\Cloud Options

Option	Description
cloudDecorator	Defines the decorator for the cloud. Can either be the name of the class which should be loaded by the plugin manager, an instance of Zend\Tag\Cloud\Decorator\AbstractCloud or an array containing the decorator under the key decorator and optionally an array under the key options, which will be passed to the decorator’s constructor.
tagDecorator	Defines the decorator for individual tags. This can either be the name of the class which should be loaded by the plugin manager, an instance of Zend\Tag\Cloud\Decorator\AbstractTag or an array containing the decorator under the key decorator and optionally an array under the key options, which will be passed to the decorator’s constructor.
decoratorPluginManager	A different plugin manager to use. Must be an instance of Zend\ServiceManager\AbstractPluginManager.
itemList	A different item list to use. Must be an instance of Zend\Tag\ItemList.
tags	A array of tags to assign to the cloud. Each tag must either implement Zend\Tag\TaggableInterface or be an array which can be used to instantiate Zend\Tag\Item.

Using Zend\Tag\Cloud

This example illustrates a basic example of how to create a tag cloud, add multiple tags to it and finally render it.

// Create the cloud and assign static tags to it
$cloud = new Zend\Tag\Cloud(array(
    'tags' => array(
        array(
            'title'  => 'Code',
            'weight' => 50,
            'params' => array('url' => '/tag/code'),
        ),
        array(
            'title'  => 'Zend Framework',
            'weight' => 1,
            'params' => array('url' => '/tag/zend-framework'),
        ),
        array(
            'title' => 'PHP',
            'weight' => 5,
            'params' => array('url' => '/tag/php'),
        ),
    ),
));

// Render the cloud
echo $cloud;

This will output the tag cloud with the three tags, spread with the default font-sizes:

<ul class="zend-tag-cloud">
    <li>
        <a href="/tag/code" style="font-size: 20px;">
            Code
        </a>
    </li>
    <li>
        <a href="/tag/zend-framework" style="font-size: 10px;">
            Zend Framework
        </a>
    </li>
    <li>
        <a href="/tag/php" style="font-size: 11px;">
            PHP
        </a>
    </li>
</ul>

Note

The HTML code examples are preformatted for a better visualization in the documentation.

You can define a output separator for the HTML Cloud decorator.

The following example shows how create the same tag cloud from a Zend\Config\Config object.

# An example tags.ini file
tags.1.title = "Code"
tags.1.weight = 50
tags.1.params.url = "/tag/code"
tags.2.title = "Zend Framework"
tags.2.weight = 1
tags.2.params.url = "/tag/zend-framework"
tags.3.title = "PHP"
tags.3.weight = 2
tags.3.params.url = "/tag/php"

// Create the cloud from a Zend\Config\Config object
$config = Zend\Config\Factory::fromFile('tags.ini');
$cloud = new Zend\Tag\Cloud($config);

// Render the cloud
echo $cloud;

Decorators

Zend\Tag\Cloud requires two types of decorators to be able to render a tag cloud. This includes a decorator which renders the single tags as well as a decorator which renders the surrounding cloud. Zend\Tag\Cloud ships a default decorator set for formatting a tag cloud in HTML. This set will, by default, create a tag cloud as ul/li -list, spread with different font-sizes according to the weight values of the tags assigned to them.

HTML Tag decorator

The HTML tag decorator will by default render every tag in an anchor element, surrounded by a <li> element. The anchor itself is fixed and cannot be changed, but the surrounding element(s) can.

Note

URL parameter

As the HTML tag decorator always surounds the tag title with an anchor, you should define a URL parameter for every tag used in it.

The tag decorator can either spread different font-sizes over the anchors or a defined list of classnames. When setting options for one of those possibilities, the corresponding one will automatically be enabled. The following configuration options are available:

HTML Tag decorator Options

Option	Default	Description
fontSizeUnit	px	Defines the font-size unit used for all font-sizes. The possible values are: em, ex, px, in, cm, mm, pt, pc and %.
minFontSize	10	The minimum font-size distributed through the tags (must be numeric).
maxFontSize	20	The maximum font-size distributed through the tags (must be numeric).
classList	null	An array of classes distributed through the tags.
htmlTags	array('li')	An array of HTML tags surrounding the anchor. Each element can either be a string, which is used as element type, or an array containing an attribute list for the element, defined as key/value pair. In this case, the array key is used as element type.

The following example shows how to create a tag cloud with a customized HTML tag decorator.

 $cloud = new Zend\Tag\Cloud(array(
     'tagDecorator' => array(
         'decorator' => 'htmltag',
         'options'   => array(
             'minFontSize' => '20',
             'maxFontSize' => '50',
             'htmlTags'    => array(
                 'li' => array('class' => 'my_custom_class'),
             ),
         ),
     ),
     'tags' => array(
        array(
            'title'  => 'Code',
            'weight' => 50,
            'params' => array('url' => '/tag/code'),
        ),
        array(
            'title'  => 'Zend Framework',
            'weight' => 1,
            'params' => array('url' => '/tag/zend-framework'),
        ),
        array(
            'title'  => 'PHP',
            'weight' => 5,
            'params' => array('url' => '/tag/php')
        ),
    ),
 ));

 // Render the cloud
 echo $cloud;

The output:

<ul class="zend-tag-cloud">
    <li class="my_custom_class">
        <a href="/tag/code" style="font-size: 50px;">Code</a>
    </li>
    <li class="my_custom_class">
        <a href="/tag/zend-framework" style="font-size: 20px;">Zend Framework</a>
    </li>
    <li class="my_custom_class">
        <a href="/tag/php" style="font-size: 23px;">PHP</a>
    </li>
</ul>

HTML Cloud decorator

By default the HTML cloud decorator will surround the HTML tags with a <ul> element and add no separation. Like in the tag decorator, you can define multiple surrounding HTML tags and additionally define a separator. The available options are:

HTML Cloud decorator Options

Option	Default	Description
separator	' ' (a whitespace)	Defines the separator which is placed between all tags.
htmlTags	array('ul' => array('class' => 'zend-tag-cloud'))	An array of HTML tags surrounding all tags. Each element can either be a string, which is used as element type, or an array containing an attribute list for the element, defined as key/value pair. In this case, the array key is used as element type.

// Create the cloud and assign static tags to it
$cloud = new Zend\Tag\Cloud(array(
    'cloudDecorator' => array(
        'decorator' => 'htmlcloud',
        'options'   => array(
            'separator' => "\n\n",
            'htmlTags'  => array(
                'ul' => array(
                    'class' => 'my_custom_class',
                    'id'    => 'tag-cloud',
                ),
            ),
        ),
    ),
    'tags' => array(
        array(
            'title'  => 'Code',
            'weight' => 50,
            'params' => array('url' => '/tag/code'),
        ),
        array(
            'title'  => 'Zend Framework',
            'weight' => 1,
            'params' => array('url' => '/tag/zend-framework'),
        ),
        array(
            'title' => 'PHP',
            'weight' => 5,
            'params' => array('url' => '/tag/php'),
        ),
    ),
));

// Render the cloud
echo $cloud;

The ouput:

<ul class="my_custom_class" id="tag-cloud"><li><a href="/tag/code" style="font-size: 20px;">Code</a></li>

<li><a href="/tag/zend-framework" style="font-size: 10px;">Zend Framework</a></li>

<li><a href="/tag/php" style="font-size: 11px;">PHP</a></li></ul>