Creating Tag Cloud Portlet

Tag cloud displays a list of post tags with visual decorations hinting the popularity of each individual tag.

1. Creating TagCloud Class ¶

We create the TagCloud class in the file /wwwroot/blog/protected/components/TagCloud.php. The file has the following content:

Yii::import('zii.widgets.CPortlet');
 
class TagCloud extends CPortlet
{
    public $title='Tags';
    public $maxTags=20;
 
    protected function renderContent()
    {
        $tags=Tag::model()->findTagWeights($this->maxTags);
 
        foreach($tags as $tag=>$weight)
        {
            $link=CHtml::link(CHtml::encode($tag), array('post/index','tag'=>$tag));
            echo CHtml::tag('span', array(
                'class'=>'tag',
                'style'=>"font-size:{$weight}pt",
            ), $link)."\n";
        }
    }
}

Unlike the UserMenu portlet, the TagCloud portlet does not use a view. Instead, its presentation is done in the renderContent() method. This is because the presentation does not contain much HTML tags.

We display each tag as a hyperlink to the post index page with the corresponding tag parameter. The font size of each tag link is adjusted according to their relative weight among other tags. If a tag has higher frequency value than the other, it will have a bigger font size.

2. Using TagCloud Portlet ¶

Usage of the TagCloud portlet is very simple. We modify the layout file /wwwroot/blog/protected/views/layouts/column2.php as follows,

......
<div id="sidebar">
 
    <?php if(!Yii::app()->user->isGuest) $this->widget('UserMenu'); ?>
 
    <?php $this->widget('TagCloud', array(
        'maxTags'=>Yii::app()->params['tagCloudCount'],
    )); ?>
 
</div>
......