I have a check box showing on all widgets, a simple option to double the size of the widget on the frontent.

function doublesize_option( $widget, $return, $instance ) {
    $large = isset( $instance['large'] ) ? $instance['large'] : '';
    ?>
        <p>
            <input class="checkbox" type="checkbox" id="<?php echo $widget->get_field_id('large'); ?>" name="<?php echo $widget->get_field_name('large'); ?>" <?php checked( true , $large ); ?> />
            <label for="<?php echo $widget->get_field_id('large'); ?>">
                <?php _e( 'Double size', 'double_textdomain' ); ?>
            </label>
        </p>
    <?php} add_filter('in_widget_form', 'doublesize_option', 10, 3 ); function doublesize_save( $instance, $new_instance ) {
if (!empty( $new_instance['large'] ) ) {
    $new_instance['large'] = 1;
}
return $new_instance; } add_filter( 'widget_update_callback', 'doublesize_save', 10, 2 );

What I can't seem to be able to do is insert a class on the widget frontend display something like

I have a check box showing on all widgets, a simple option to double the size of the widget on the frontent.

function doublesize_option( $widget, $return, $instance ) {
    $large = isset( $instance['large'] ) ? $instance['large'] : '';
    ?>
        <p>
            <input class="checkbox" type="checkbox" id="<?php echo $widget->get_field_id('large'); ?>" name="<?php echo $widget->get_field_name('large'); ?>" <?php checked( true , $large ); ?> />
            <label for="<?php echo $widget->get_field_id('large'); ?>">
                <?php _e( 'Double size', 'double_textdomain' ); ?>
            </label>
        </p>
    <?php} add_filter('in_widget_form', 'doublesize_option', 10, 3 ); function doublesize_save( $instance, $new_instance ) {
if (!empty( $new_instance['large'] ) ) {
    $new_instance['large'] = 1;
}
return $new_instance; } add_filter( 'widget_update_callback', 'doublesize_save', 10, 2 );

What I can't seem to be able to do is insert a class on the widget frontend display something like

• php
• customization
• custom-field
• widgets

• When you say "widget frontend" do you mean in the widget editor in the admin area or the public facing website? – jdm2112 Commented Sep 9, 2020 at 12:56

1 Answer 1

I eventually use the following to be able to do it:

add_filter('dynamic_sidebar_params', function($params) {
global $wp_registered_widgets;
$this_widget_id = $params[0]['widget_id'];
$this_widget = $wp_registered_widgets[$this_widget_id];
$widget_object = $this_widget['callback'][0];
$all_settings = get_option($widget_object->option_name);
$saved_settings = $all_settings[$params[1]['number']];
if ($saved_settings['myclass']) {
    $classe_to_add = 'myclass ';
    $classe_to_add = 'class=" '.$classe_to_add;
    $params[0]['before_widget'] = str_replace('class="',$classe_to_add,$params[0]['before_widget']);
}
return $params;

});