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function is not described

_mce_set_direction() WP 2.1.0

Set the localized direction for MCE plugin.

Will only set the direction to 'rtl', if the WordPress locale has the text direction set to 'rtl'.

Fills in the 'directionality' setting, enables the 'directionality' plugin, and adds the 'ltr' button to 'toolbar1', formerly 'theme_advanced_buttons1' array keys. These keys are then returned in the $mce_init (TinyMCE settings) array.

No Hooks.

Return

Array. Direction set for 'rtl', if needed by locale.

Usage

_mce_set_direction( $mce_init );
$mce_init(array) (required)
MCE settings array.

Code of mce set direction: wp-includes/functions.php VER 5.0.3

<?php
function _mce_set_direction( $mce_init ) {
	if ( is_rtl() ) {
		$mce_init['directionality'] = 'rtl';
		$mce_init['rtl_ui'] = true;

		if ( ! empty( $mce_init['plugins'] ) && strpos( $mce_init['plugins'], 'directionality' ) === false ) {
			$mce_init['plugins'] .= ',directionality';
		}

		if ( ! empty( $mce_init['toolbar1'] ) && ! preg_match( '/\bltr\b/', $mce_init['toolbar1'] ) ) {
			$mce_init['toolbar1'] .= ',ltr';
		}
	}

	return $mce_init;
}