This article requires to be familiar with markItUp! concept and settings. I won't explain them here.
Please, visit the official markItUp! website for info and documentation:
http://markitup.jaysalvat.com/documentation/
First of all:

• Download latest release of markItUp! at http://markitup.jaysalvat.com/downloads/.
• Add 'markitup' folder in /webroot/js/.
• Download latest release of jQuery at http://jquery.com/.
• Add jQuery script in a new 'jquery' folder in /webroot/js/.
• Create a new markitup.php file in /views/helpers/ and copy/paste the helper code below.

Usage

markItUp! generation helper

$markitup->editor($fieldName, [$options]); It basically behaves as the $form->input() helper but accepts more options.
By default these options are set to:

• set => 'default', the folder of the set.
• settings' => 'mySettings', the name of the object in the set.
• skin' => 'markitup', the skin of the editor.
• parser => '', path to a controller/action to render the preview.

View Template:


<h1>My Post form</h1>
<?php echo $form->create('Posts'); ?>
<?php echo $markitup->editor('Posts.article'); ?>
<?php echo $form->end('Validate'); ?>


Removal link helper

$markitup->destroy($title, $fieldName, [$htmlAttributes, $confirmMessage]); Creates a link to remove markItUp! from a textfield.
It basically behaves as the $html->link() helper but needs $fieldName.

View Template:


<h1>My Post form</h1>
<?php echo $markitup->destroy("Remove markItUp! from the textarea", 'Posts.article') ?>
<?php echo $form->create('Posts'); ?>
<?php echo $markitup->editor('Posts.article'); ?>
<?php echo $form->end('Validate'); ?>


Creation link helper

$markitup->create($title, $fieldName, [$options, $htmlAttributes, $confirmMessage]); Creates a link to add markItUp! to an existing textfield or switching settings.
It basically behaves as the $html->link() helper but needs $fieldName.
By default the options are:

• set => 'default', the folder of the toolbar set
• settings' => 'mySettings', the name of the settings in the set.js file
• skin' => 'markitup', the skin of the editor
• parser => '', path to a controller/action to render the preview.

View Template:


<h1>My Post form</h1>
<?php echo $markitup->create("Add markItUp! to the textarea", 'Posts.article'); ?>
<?php echo $form->create('Posts'); ?>
<?php echo $form->input('Posts.article'); ?>
<?php echo $form->end('Validate'); ?>


Insertion link helper

$markitup->insert($title, [$fieldName], $content, [$htmlAttributes, $confirmMessage]); Creates a link to insert content in a markItUp! editor. It basically behaves as the $html->link() helper but needs $fieldName and $content.

• $fieldName is optional, if it's null, the focused editor will receive the content.
• $content is either a string or an array of markItUp! properties (openWith, closeWith, replaceWith, placeHolder, ...).

See markItUp! documentation for more information:
http://markitup.jaysalvat.com/documentation

View Template:


<h1>My Post form</h1>
<?php echo $markitup->insert("Insert bold text", 'Posts.article',
                                   array( 'openWith' => '<strong>',
                                          'closeWith' => '</strong>',
                                          'placeHolder' => 'Bold text here'));
?>
<?php echo $form->create('Posts'); ?>
<?php echo $markitup->editor('Posts.article'); ?>
<?php echo $form->end('Validate'); ?>


Preview parsing helper

$markitup->parse($content, [$parser]); Renders the content with a markup parser.
For more information, see BBcode example below.

Preview

markItUp! uses its own template system to display Html built-in preview. You can find and customize this template in /webroot/js/markitup/templates/.
In order to keep MVC structure and CakePhp logic, you can set a controller and action to preview the content.
So create and edit a 'preview.ctp' in the 'layouts' folder and proceed as below:

View Template:


<?php echo $form->create('Posts'); ?>
<?php echo $markitup->editor('Posts.article', array('parser' => '/posts/preview/')); ?>
<?php echo $form->end('Validate'); ?>


Controller Class:

<?php 
class postsController extends AppController{
    var $name = 'posts';
    var $helpers = array('Markitup');

    function index() {
        // ...
    }
    
    function preview() {
        $this->layout = 'preview';
        $this->set('content', $this->data);
    }
}
?>
Edit your preview.ctp file...

View Template:


<?php echo $content ?>


markItUp! and BBcode Example

By default markItUp! is provided as a Html editor, but you can download various kinds of sets and parsers: Textile, Markdown, BBcode...
For the example, let's set markItUp! as a BBcode editor.

• Download the BBcode set at http://markitup.jaysalvat.com/downloads/.
• Add the BBcode set in /webroot/js/markitup/sets/bbcode/
• Download a BBcode parser at http://markitup.jaysalvat.com/downloads/.
• Drop the .php file in /vendor/bbcode/

View Template:


<h1>My Post form</h1>
<?php echo $form->create('Posts'); ?>
<?php echo $markitup->editor('Posts.article',
                                 array( 'set' => 'bbcode',
                                        'parser' => '/posts/preview/bbcode'));
?>
<?php echo $form->end('Validate'); ?>


Controller Class:

<?php 
class postsController extends AppController{
    var $name = 'posts';
    var $helpers = array('Markitup');

    function index() {
        // ...
    }
    
    function preview($parser = '') {
        $this->layout = 'preview';
        $this->set('parser', $parser);        
        $this->set('content', $this->data);
        $this->autoRender = true;
    }
}
?>
Edit your preview.ctp file...

View Template:


<?php echo $markitup->parse($content, $parser) ?>

This Helper is designed to be used with several kinds of parsers in a same project.
Edit the Helper at line 100 to work with the BBcode parser added to the /vendor folder.

switch($parser) {
       case 'bbcode':
           // App::import('Vendor', 'bbcode', array('file' => 'markitup.bbcode-parser'));
           // $parsed = myBbcodeParser($content);        
           break;
       case 'textile':
           // App::import('Vendor', 'textile', array('file' => 'myTextileParser'));
           // $parsed = myTextileParser($content);        
           break;
    //...


The code

Copy and paste the code below in /views/helpers/markitup.php

Helper Class:

<?php 
<?
/**
 * markItUp! Helpers
 * @author Jay Salvat
 * @version 1.0
 *
 * Download markItUp! at:
 * http://markitup.jaysalvat.com
 * Download jQuery at:
 * http://jquery.com
 */
class MarkitupHelper extends AppHelper {
    var $helpers = array('Html', 'Form', 'Javascript');
    
    /**
     * Generates a form textarea element complete with label and wrapper div with markItUp! applied.
     * @param  string $fieldName This should be "Modelname.fieldname"
     * @param  array $settings
     * @return string  An <textarea /> element.
     */
    function editor($name, $settings = array()) {
        $config = $this->_build($settings);
        $settings = $config['settings'];
        $default = $config['default'];
        $textarea = array_diff_key($settings, $default);
        $textarea = am($textarea, array('type' => 'textarea'));
        $editor = $this->Form->input($name, $textarea);
        $id = '#'.parent::domId($name);
        $editor.= $this->Javascript->codeBlock('jQuery.noConflict();jQuery(function() { jQuery("'.$id.'").markItUp('.$settings['settings'].', { previewParserPath:"'.$settings['parser'].'" } ); });');
        return $this->output($editor);
    }

    /**
     * Link to build markItUp! on a existing textfield
     * @param  string $title The content to be wrapped by <a> tags.
     * @param  string $fieldName This should be "Modelname.fieldname" or specific domId as #id.
     * @param  array  $settings
     * @param  array  $htmlAttributes Array of HTML attributes.
     * @param  string $confirmMessage JavaScript confirmation message.
     * @return string An <a /> element.    
     */
    function create($title, $fieldName = "", $settings = array(), $htmlAttributes = array(), $confirmMessage = false) {
        $id = ($fieldName{0} === '#') ? $fieldName : '#'.parent::domId($fieldName);
        
        $config = $this->_build($settings);
        $settings = $config['settings'];
        $htmlAttributes = am($htmlAttributes, array('onclick' => 'jQuery("'.$id.'").markItUpRemove(); jQuery("'.$id.'").markItUp('.$settings['settings'].', { previewParserPath:"'.$settings['parser'].'" }); return false;'));
        return $this->Html->link($title, "#", $htmlAttributes, $confirmMessage, false);
    }    

    /**
     * Link to destroy a markItUp! editor from a textfield
     * @param string  $title The content to be wrapped by <a> tags.
     * @param string  $fieldName This should be "Modelname.fieldname" or specific domId as #id.
     * @param array   $htmlAttributes Array of HTML attributes.
     * @param string  $confirmMessage JavaScript confirmation message.
     * @return string An <a /> element.    
     */
    function destroy($title, $fieldName = "", $htmlAttributes = array(), $confirmMessage = false) {
        $id = ($fieldName{0} === '#') ? $fieldName : '#'.parent::domId($fieldName);
        $htmlAttributes = am($htmlAttributes, array('onclick' => 'jQuery("'.$id.'").markItUpRemove(); return false;'));
        return $this->Html->link($title, "#", $htmlAttributes, $confirmMessage, false);
    }

    /**
     * Link to add content to the focused textarea
     * @param string  $title The content to be wrapped by <a> tags.
     * @param string  $fieldName This should be "Modelname.fieldname" or specific domId as #id.
     * @param mixed   $content String or array of markItUp! options (openWith, closeWith, replaceWith, placeHolder and more. See markItUp! documentation for more details : http://markitup.jaysalvat.com/documentation
     * @param array   $htmlAttributes Array of HTML attributes.
     * @param string  $confirmMessage JavaScript confirmation message.
     * @return string An <a /> element.    
     */
    function insert($title, $fieldName = null, $content = array(), $htmlAttributes = array(), $confirmMessage = false) {
        if (isset($fieldName)) {
            $content['target'] = ($fieldName{0} === '#') ? $fieldName : '#'.parent::domId($fieldName);
        }
        if (!is_array($content)) {
            $content['replaceWith'] = $content;
        }
        $properties = '';
        foreach($content as $k => $v) {
            $properties .= $k.':"'.addslashes($v).'",';
        }
        $properties = substr($properties, 0, -1);
        
        $htmlAttributes = am($htmlAttributes, array('onclick' => '$.markItUp( { '.$properties.' } ); return false;'));
        return $this->Html->link($title, "#", $htmlAttributes, $confirmMessage, false);
    }

    /**
     * Parser to use in the preview
     * @param string  $content The content to be parsed.
     * @return string Parsed content.    
     */
    function parse($content, $parser = '') {
    // This Helper is designed to be used with several kinds of parser
    // in a same project.
        // Drop your favorite parsers in the /vendor/ folder and edit lines below.
        switch($parser) {
            case 'bbcode':
                // App::import('Vendor', 'bbcode', array('file' => 'myFavoriteBbcodeParser'));
                // $parsed = myFavoriteBbcodeParser($content);        
                break;
            case 'textile':
                // App::import('Vendor', 'textile', array('file' => 'myFavoriteTextileParser'));
                // $parsed = myFavoriteTextileParser($content);        
                break;
            case 'markdown':
                // App::import('Vendor', 'markdown', array('file' => 'myFavoriteMarkDownParser'));
                // $parsed = myFavoriteMarkDownParser($content);            
                break;
            default:
                // App::import('Vendor', 'favorite', array('file' => 'myFavoriteFavoriteParser'));
                // $parsed = myFavoriteFavoriteParser($content);
        }
        return $content;
    }
    
    /**
     * Adds jQuery and markItUp! scripts to the page
     */    
    function beforeRender() {
        $this->Javascript->link('jquery/jquery.js', false);
        $this->Javascript->link('markitup/jquery.markitup.js', false);
    }

    /**
     * Private function.
     * Builds the settings array and add includes.
     */    
    function _build($settings) {
        $default = array(   'set' => 'default', 
                            'skin' => 'markitup', 
                            'settings' => 'mySettings',
                            'parser' => '');
        $settings = am($default, $settings);
        if ($settings['parser']) {
            $settings['parser'] = $this->Html->url($settings['parser']);
        }                
        $this->Javascript->link('markitup/sets/'.$settings['set'].'/set.js', false);
        $this->Html->css('/js/markitup/skins/'.$settings['skin'].'/style.css', null, null, false);
        $this->Html->css('/js/markitup/sets/'.$settings['set'].'/style.css', null, null, false);

        return array('settings' => $settings, 'default' => $default);
    }
}
?>
?>
Enjoy,
Feel free to correct my english and post comments.