Creating tag clouds

Zend\Tag\Cloud is the rendering aspect of zend-tag. By default, it comes with a set of HTML decorators, allowing you to create tag clouds for a website. It also supplies you with two abstract classes to create your own decorators; one use case might be to create tag clouds in PDF documents.

You can instantiate and configure Zend\Tag\Cloud either programmatically or via a configuration sturcture (either an array or an instance of Traversable).

The following options are available:

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([
    'tags' => [
        [
            'title'  => 'Code',
            'weight' => 50,
            'params' => ['url' => '/tag/code'],
        ],
        [
            'title'  => 'Zend Framework',
            'weight' => 1,
            'params' => ['url' => '/tag/zend-framework'],
        ],
        [
            'title' => 'PHP',
            'weight' => 5,
            'params' => ['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>

Formatting

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:

• A decorator for rendering an individual tag.
• A decorator for rendering 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 a <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.

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:

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

$cloud = new Zend\Tag\Cloud([
    'tagDecorator' => [
        'decorator' => 'htmltag',
        'options'   => [
            'minFontSize' => '20',
            'maxFontSize' => '50',
            'htmlTags'    => [
                'li' => ['class' => 'my_custom_class'],
            ],
        ],
    ],
    'tags' => [
       [
           'title'  => 'Code',
           'weight' => 50,
           'params' => ['url' => '/tag/code'],
       ],
       [
           'title'  => 'Zend Framework',
           'weight' => 1,
           'params' => ['url' => '/tag/zend-framework'],
       ],
       [
           'title'  => 'PHP',
           'weight' => 5,
           'params' => ['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 the tag decorator, you can define multiple surrounding HTML tags and additionally define a separator. The available options are:

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

// Render the cloud
echo $cloud;

The output:

<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>