softark/yii2-mb-captcha Yii2 Multibyte CAPTCHA


  1. Description
  2. Requirements
  3. Usage
  4. Properties of softark\mbcaptcha\Captcha
  5. Properties of softark\mbcaptcha\CaptchaAction
  6. How to Customize
  7. History
  8. Acknowledgment

Multibyte captcha widget for Yii framework 2.0.

Multibyte Captcha in Action

Multibyte Captcha using Chinese characters



softark\mbcaptcha\Captcha is an extension to yii\captcha\Captcha.

While yii\captcha\Captcha renders a CAPTCHA image only with English alphabets, softark\mbcaptcha\Captcha can render it with multibyte characters ... Japanese Hirakana by default, but you may use any multibyte characters by providing the appropriate font.

Optionally softark\mbcaptcha\Captcha may render a link next to the CAPTCHA image which will enable you to toggle the CAPTCHA type from the multibyte character to English alphabet, and vice versa.

softark\mbcaptcha\Captcha must be used together with softark\mbcaptcha\CaptchaAction to provide its feature.


  • Yii Version 2.0.44 or later
  • PHP GD + FreeType extension or ImageMagick extension


  1. Add softark/yii2-mb-captcha in your project's composer.json, and let Composer configure your project.

    `php "require": {

     "php": ">=5.4.0",
     "yiisoft/yii2": "~2.0.44",
     "yiisoft/yii2-bootstrap": "*",
     "yiisoft/yii2-swiftmailer": "*",
     "softark/yii2-mb-captcha": "dev-master"

    }, `

  2. Use softark\mbcaptcha\Captcha in place of yii\captcha\Captcha in your view.

    `php / use yii\captcha\Captcha; / use softark\mbcaptcha\Captcha; ... <?=

     $form->field($model, 'verifyCode')->widget(Captcha::className(), [
         'template' => '<div class="row"><div class="col-lg-3">{image}</div><div class="col-lg-6">{input}</div></div>',
     ]) ?>


    Optionally you may want to include {link} token in your template. `php / use yii\captcha\Captcha; / use softark\mbcaptcha\Captcha; <?=

     $form->field($model, 'verifyCode')->widget(Captcha::className(), [
         'template' => '<div class="row"><div class="col-lg-3">{image} {link}</div><div class="col-lg-6">{input}</div></div>',
     ]) ?>


  3. Use softark\mbcaptcha\CaptchaAction in place of yii\captcha\CaptchaAction in your controller.

    `php public function actions() {

     return [
         'captcha' => [
             /* 'class' => 'yii\captcha\CaptchaAction', */
             'class' => 'softark\mbcaptcha\CaptchaAction',
             'fixedVerifyCode' => YII_ENV_TEST ? 'testme' : null,

    } `

Properties of softark\mbcaptcha\Captcha

softark\mbcaptcha\Captcha supports all the properties of yii\captcha\Captcha and the following ones. The items with *()** are the basic options that you may want to configure.

  1. *template ()** @var string

    The template for arranging the CAPTCHA widget. Defaults to '{image} {link} {input}'.

    This property is inherited from the parent and is extended to support the type toggling link tag. In this template, the tokens {image}, {link} and {input} will be replaced with the actual image tag, the type toggling link tag and the text input tag respectively.

    Note that {link} must be a sibling of {image} in the DOM tree, otherwise the toggling link won't work.

    You may omit {link} token if you don't want the type toggling link tag.

  2. *toggleLinkLabel ()** @var string

    The label of the type toggling link. Defaults to "かな/abc" ("Japanese Hirakana/lower-case alphabet").

    You may want to change this label when you use non-Japanese characters.

Properties of softark\mbcaptcha\CaptchaAction

softark\mbcaptcha\CaptchaAction supports all the properties of yii\captcha\CaptchaAction and the following additional ones. The items with *()** are the basic options that you may want to configure.

  1. *mbFontFile ()** @var string

    The font to be used for multibyte characters. Defaults to seto-mini.ttf.

    Note that the default font only supports standard ASCII and Japanese Hirakana and Katakana.

    You have to provide an appropriate font file if you want to render your choice of characters.

  2. *seeds ()** @var string

    The string used for generating the random word. Several characters randomly selected from this string will make up the captcha word.

    Defaults to a series of Japanese Hirakana characters: "あいうえおかきくけこがぎぐげごさしすせそざじずぜぞたちつてとだぢづでどなにぬねのはひふへほはひふへほはひふへほばびぶべぼぱぴぷぺぽまみむめもやゆよらりるれろわをん".

    You may set your own. Make sure that your mbFontFile can render all the characters in the seeds.

  3. mbMinLength @var integer

    The minimum length for randomly generated multibyte character word. Defaults to 5

  4. mbMaxLength @var integer

    The maximum length for randomly generated multibyte character word. Defaults to 5

  5. mbOffset @var integer

    The offset between characters. Defaults to 2. You can adjust this property in order to decrease or increase the readability of the multibyte character captcha.

  6. fixedAngle @var boolean

    Whether to render the multibyte character captcha image with a fixed angle. Defaults to false. You may want to set this to true if you have trouble rendering your font.

How to Customize

The following is a sample code that shows how to customize softark\mbcaptcha\Captcha and softark\mbcaptcha\CaptchaAction. It shows Chinese characters for the captcha.

In the view script:

use softark\mbcaptcha\Captcha;
    $form->field($model, 'verifyCode')->widget(Captcha::className(), [
        'template' => '<div class="row"><div class="col-lg-3">{image} {link}</div><div class="col-lg-6">{input}</div></div>',
        'toggleLinkLabel' => '漢字/abc',
    ]) ?>

And in the controller:

public function actions()
    return [
        'captcha' => [
            'class' => 'softark\mbcaptcha\CaptchaAction',
            'seeds' => '几乎所有的应用程序都是建立在数据库之上虽然可以非常灵活的' .
                '操作数据库但有些时候一些设计的选择可以使它更便于使用首先应用程序' .
                '广泛使用了设计的考虑主要围绕优化使用而不是组成复杂语句实际上大多' .
                '的设计是使用友好的模式来解决实践中的问题最常用的方式是创建易于被' .
            'mbFontFile' => '@frontend/fonts/gbsn00lp.ttf',

Note that the sample code assumes that you have placed your choice of font file in the 'fonts' sub-directory of your frontend application directory.

You have to be careful not to include the characters in seeds that are not supported by your font.


  • Version 1.0.0 (2014-11-15)
    • Tested on Yii 2.0.0
    • Adopted the code style of the core (spaces for indentation)
  • Version 0.9.0 (2014-04-22)
    • Update for Yii 2.0 beta
  • Version 0.8.0 (2014-02-08)
    • Initial release
    • Ported from JCaptcha 1.0.3, which is for Yii 1.1.x.
    • Developed under Yii 2.0 alpha


Many thanks to the author of the wonderful work of setofont.ttf. The default font "seto-mini.ttf" is a subset of setofont.ttf.

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1 follower
Yii Version: 2.0
License: BSD-3-Clause
Category: Security
Developed by: softark
Created on: Apr 8, 2018
Last updated: (not set)
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