Creating the theme class

lightbox-sample.php

<?php
class Optin_Monster_Lightbox_Theme_Sample extends Optin_Monster_Theme {
	    
    /**
     * Path to the file.
     *
     * @var string
     */
    public $file = __FILE__;

    /**
     * Slug of the theme.
     *
     * @var string
     */
    public $theme = 'sample';

    /**
     * The width of the image for the optin.
     * This is only needed if the theme has an image
     *
     * @var int
     */
    public $img_width = 230;

    /**
     * The height of the image for the optin.
     * This is only needed if the theme has an image
     *
     * @var int
     */
    public $img_height = 195;

    /**
     * Primary class constructor.
     *
     * The constructor must invoke the parent constructor
     *
     * @param int $optin_id The optin ID to target.
     */
    public function __construct( $optin_id ) {

        // Construct via the parent object.
        parent::__construct( $optin_id );

        // Set the optin type.
        $this->type = $this->meta['type'];

    }
    
    /**
     * Retrieval method for getting the styles for a theme.
     *
     * @return string A string of concatenated CSS for the theme.
     */
    public function get_styles() {
    	
    	// All of the theme styles will go here
    	
    }
    
    /**
     * Retrieval method for getting the HTML output for a theme.
     *
     * @return string A string of HTML for the theme.
     */
    public function get_html() {
    	
    	// The optin HTML is returned by this method
    	
    }
    
    /**
     * Retrieval method for getting any custom JS for a theme.
     *
     * @return string A string of JS for the theme.
     */
    public function get_js() {
	
    }
    
    /**
     * Outputs the filters needed to register controls for the OptinMonster
     * preview customizer and save the fields registered.
     */
    public function controls() {

        add_filter( 'optin_monster_panel_design_fields', array( $this, 'design_fields' ), 10, 2 );
        add_filter( 'optin_monster_panel_input_fields', array( $this, 'input_fields' ), 10, 2 );
        add_filter( 'optin_monster_save_optin', array( $this, 'save_controls' ), 10, 4 );

    }
    
    /**
     * Outputs the design controls for the theme.
     *
     * Each field should be added to the $fields array with a unique slug.
     *
     * @param array $fields    Array of design fields.
     * @param object $instance The Edit UI instance.
     * @return array $fields   Amended array of design fields.
     */
    public function design_fields( $fields, $instance ) {
	
	// We'll create the design fields here (background color, border color, etc.)
	
    }
    
    /**
     * Outputs the fields controls for the theme.
     *
     * @param array $fields    Array of input fields.
     * @param object $instance The Edit UI instance.
     * @return array $fields   Amended array of input fields.
     */
    public function input_fields( $fields, $instance ) {
    	
    	// Our input fields (name, email & submit) go here
    	
    }
    
    /**
     * Saves the meta fields for the optin controls.
     *
     * @param array $meta      The meta key "_om_meta" with all of its data.
     * @param int $optin_id    The optin ID to target.
     * @param array $fields    The post fields under the key "optin_monster".
     * @param array $post_data All of the $_POST contents generated when saving.
     * @return array $meta     Amended array of meta to be saved.
     */
    public function save_controls( $meta, $optin_id, $fields, $post_data ) {
    	
    	// Now we'll get everything saved properly.
    	
    }
}