wp_register_widget_control( int|string $id, string $name, callable $control_callback, array $options = array(), mixed $params )

注册控件控件回调以自定义选项。
Registers widget control callback for customizing options.

源码（Source）

/**
 * Registers widget control callback for customizing options.
 *
 * The options contains the 'height', 'width', and 'id_base' keys. The 'height'
 * option is never used. The 'width' option is the width of the fully expanded
 * control form, but try hard to use the default width. The 'id_base' is for
 * multi-widgets (widgets which allow multiple instances such as the text
 * widget), an id_base must be provided. The widget id will end up looking like
 * `{$id_base}-{$unique_number}`.
 *
 * @since 2.2.0
 *
 * @todo Document `$options` as a hash notation, re: WP_Widget::__construct() cross-reference.
 * @todo `$params` parameter?
 *
 * @global array $wp_registered_widget_controls
 * @global array $wp_registered_widget_updates
 * @global array $wp_registered_widgets
 * @global array $_wp_deprecated_widgets_callbacks
 *
 * @param int|string   $id               Sidebar ID.
 * @param string       $name             Sidebar display name.
 * @param callback     $control_callback Run when sidebar is displayed.
 * @param array|string $options          Optional. Widget options. See description above. Default empty array.
 */
function wp_register_widget_control( $id, $name, $control_callback, $options = array() ) {
	global $wp_registered_widget_controls, $wp_registered_widget_updates, $wp_registered_widgets, $_wp_deprecated_widgets_callbacks;

	$id = strtolower($id);
	$id_base = _get_widget_id_base($id);

	if ( empty($control_callback) ) {
		unset($wp_registered_widget_controls[$id]);
		unset($wp_registered_widget_updates[$id_base]);
		return;
	}

	if ( in_array($control_callback, $_wp_deprecated_widgets_callbacks, true) && !is_callable($control_callback) ) {
		unset( $wp_registered_widgets[ $id ] );
		return;
	}

	if ( isset($wp_registered_widget_controls[$id]) && !did_action( 'widgets_init' ) )
		return;

	$defaults = array('width' => 250, 'height' => 200 ); // height is never used
	$options = wp_parse_args($options, $defaults);
	$options['width'] = (int) $options['width'];
	$options['height'] = (int) $options['height'];

	$widget = array(
		'name' => $name,
		'id' => $id,
		'callback' => $control_callback,
		'params' => array_slice(func_get_args(), 4)
	);
	$widget = array_merge($widget, $options);

	$wp_registered_widget_controls[$id] = $widget;

	if ( isset($wp_registered_widget_updates[$id_base]) )
		return;

	if ( isset($widget['params'][0]['number']) )
		$widget['params'][0]['number'] = -1;

	unset($widget['width'], $widget['height'], $widget['name'], $widget['id']);
	$wp_registered_widget_updates[$id_base] = $widget;
}