source: trunk/www.guidonia.net/wp/wp-content/themes/atahualpa/functions/bfa_text_widget.php@ 44

<?php // create new text widgets
function widget_text($args, $widget_args = 1) {
        extract( $args, EXTR_SKIP );
        if ( is_numeric($widget_args) )
                $widget_args = array( 'number' => $widget_args );
        $widget_args = wp_parse_args( $widget_args, array( 'number' => -1 ) );
        extract( $widget_args, EXTR_SKIP );

        $options = get_option('widget_text');
        if ( !isset($options[$number]) )
                return;

        $title = apply_filters('widget_title', $options[$number]['title']);
        $text = apply_filters( 'widget_text', $options[$number]['text'] );
?>
                <?php echo $before_widget; ?>
                        <?php if ( !empty( $title ) ) { echo $before_title . $title . $after_title; } ?>
                        <div class="textwidget"><?php echo $text; ?></div>
                <?php if ( !empty( $title ) ) { echo $after_widget; } else { echo "</div>"; } ?>
<?php
}
// create new text widget controls
function widget_text_control($widget_args = 1) {
        global $wp_registered_widgets;
        static $updated = false;

        if ( is_numeric($widget_args) )
                $widget_args = array( 'number' => $widget_args );
        $widget_args = wp_parse_args( $widget_args, array( 'number' => -1 ) );
        extract( $widget_args, EXTR_SKIP );

        $options = get_option('widget_text');
        if ( !is_array($options) )
                $options = array();

        if ( !$updated && !empty($_POST['sidebar']) ) {
                $sidebar = (string) $_POST['sidebar'];

                $sidebars_widgets = wp_get_sidebars_widgets();
                if ( isset($sidebars_widgets[$sidebar]) )
                        $this_sidebar =& $sidebars_widgets[$sidebar];
                else
                        $this_sidebar = array();

                foreach ( $this_sidebar as $_widget_id ) {
                        if ( 'widget_text' == $wp_registered_widgets[$_widget_id]['callback'] && isset($wp_registered_widgets[$_widget_id]['params'][0]['number']) ) {
                                $widget_number = $wp_registered_widgets[$_widget_id]['params'][0]['number'];
                                if ( !in_array( "text-$widget_number", $_POST['widget-id'] ) ) // the widget has been removed.
                                        unset($options[$widget_number]);
                        }
                }

                foreach ( (array) $_POST['widget-text'] as $widget_number => $widget_text ) {
                        if ( !isset($widget_text['text']) && isset($options[$widget_number]) ) // user clicked cancel
                                continue;
                        $title = strip_tags(stripslashes($widget_text['title']));
                        if ( current_user_can('unfiltered_html') )
                                $text = stripslashes( $widget_text['text'] );
                        else
                                $text = stripslashes(wp_filter_post_kses( $widget_text['text'] ));
                        $options[$widget_number] = compact( 'title', 'text' );
                }

                update_option('widget_text', $options);
                $updated = true;
        }

        if ( -1 == $number ) {
                $title = '';
                $text = '';
                $number = '%i%';
        } else {
                $title = attribute_escape($options[$number]['title']);
                $text = format_to_edit($options[$number]['text']);
        }
?>
                <p>
                        <input class="widefat" id="text-title-<?php echo $number; ?>" name="widget-text[<?php echo $number; ?>][title]" type="text" value="<?php echo $title; ?>" />
                        <textarea class="widefat" rows="16" cols="20" id="text-text-<?php echo $number; ?>" name="widget-text[<?php echo $number; ?>][text]"><?php echo $text; ?></textarea>
                        <input type="hidden" name="widget-text[<?php echo $number; ?>][submit]" value="1" />
                </p>
<?php
}

// unregister old / register new text widgets

function widget_text_un_re_register() {
        if ( !$options = get_option('widget_text') )
                $options = array();
        $widget_ops = array('classname' => 'widget_text', 'description' => __('Arbitrary text or HTML','atahualpa'));
        $control_ops = array('width' => 400, 'height' => 350, 'id_base' => 'text');
        $name = __('Text','atahualpa');

        $id = false;
        foreach ( array_keys($options) as $o ) {
                // Old widgets can have null values for some reason
                if ( !isset($options[$o]['title']) || !isset($options[$o]['text']) )
                        continue;
                $id = "text-$o"; // Never never never translate an id
                unregister_sidebar_widget($id, $name, 'wp_widget_text', $widget_ops, array( 'number' => $o ));
                unregister_widget_control($id, $name, 'wp_widget_text_control', $control_ops, array( 'number' => $o ));
                wp_register_sidebar_widget($id, $name, 'widget_text', $widget_ops, array( 'number' => $o ));
                wp_register_widget_control($id, $name, 'widget_text_control', $control_ops, array( 'number' => $o ));
        }

        // If there are none, we register the widget's existance with a generic template
        if ( !$id ) {
                unregister_sidebar_widget( 'text-1', $name, 'wp_widget_text', $widget_ops, array( 'number' => -1 ) );
                unregister_widget_control( 'text-1', $name, 'wp_widget_text_control', $control_ops, array( 'number' => -1 ) );
                wp_register_sidebar_widget( 'text-1', $name, 'widget_text', $widget_ops, array( 'number' => -1 ) );
                wp_register_widget_control( 'text-1', $name, 'widget_text_control', $control_ops, array( 'number' => -1 ) );
        }
}
add_action( 'widgets_init', 'widget_text_un_re_register' )
?>