Add metabox to Genesis theme options

genesis-add-theme-options.php

<?php //* Mind this opening PHP tag

/**
 *	Register custom Genesis theme settings
 *	The new setting will store the user's license key
 *
 *	@param array $defaults Default theme settings
 *	@return array New default theme settings
 */
add_filter( 'genesis_theme_settings_defaults', 'prefix_add_genesis_theme_settings' );
function prefix_add_genesis_theme_settings( $defaults ) {

	$defaults['prefix_license_key'] = '';
	return $defaults;
}

/**
 *	Sanitize new Genesis settings
 */
add_action( 'genesis_settings_sanitizer_init', 'prefix_sanitize_custom_genesis_settings' );
function prefix_sanitize_custom_genesis_settings() {
	genesis_add_option_filter( 'no_html', GENESIS_SETTINGS_FIELD, array( 'prefix_license_key' ) );
}

/**
 *	Add custom meta box(es) to Genesis Theme Settings page
 *
 *	@param string $_genesis_theme_settings_pagehook
 */
add_action( 'genesis_theme_settings_metaboxes', 'prefix_genesis_meta_boxes' );
function prefix_genesis_meta_boxes( $_genesis_theme_settings_pagehook ) {
	add_meta_box( 'prefix-genesis-settings', __( 'My Plugin\'s Settings', 'prefix' ), 'prefix_genesis_settings_meta_box_callback', $_genesis_theme_settings_pagehook, 'main', 'high' );
}

/**
 *	Render the meta box content/fields
 *
 *	@see prefix_genesis_meta_boxes()
 */
function prefix_genesis_settings_meta_box_callback() { ?>

	<p><?php _e( 'My Plugin License Key', 'prefix' );?><br />
	<input type="text" name="<?php echo GENESIS_SETTINGS_FIELD; ?>[prefix_license_key]" value="<?php echo esc_url( genesis_get_option( 'prefix_license_key' ) ); ?>" size="60" /></p>

<?php }