yii2 captcha image doesn't show - php

Question

i have the following code in yii2 but the captcha image doesn't show !
controller:
public function actions() {
return [
'captcha' => [
'class' => 'yii\captcha\CaptchaAction',
'fixedVerifyCode' => YII_ENV_TEST ? 'testme' : null,
'foreColor' => 0xF9AF21,
'maxLength' => 5,
'minLength' => 3,
'padding' => 5,
'offset' => 1,
'transparent' => true,
'height' => 40
],
'error' => [
'class' => 'yii\web\ErrorAction',
],
];
}
model :(rules)
['verifyCode', 'captcha',],
view:
$form->field($model, 'verifyCode')->widget(Captcha::className()])

Answer 1

In SiteController look for behaviors() function, it might look like in the example bellow.
public function behaviors()
{
return [
'access' => [
'class' => AccessControl::className(),
'only' => ['logout', 'signup'],
'rules' => [
[
'actions' => ['signup'],
'allow' => true,
'roles' => ['?'],
],
[
'actions' => ['logout'],
'allow' => true,
'roles' => ['#'],
],
],
],
];
}
You will not see captcha image, if in your behaviour() function wouldn't be specified 'only' actions, like this: 'only' => ['logout', 'signup'],. This line says that apply access rules only to this actions. If you don't want to add rules to specific actions, you can add 'captcha' action to your rules, like in example below.
public function behaviors()
{
return [
'access' => [
'class' => AccessControl::className(),
'rules' => [
[
'actions' => ['signup', 'captcha'],
'allow' => true,
'roles' => ['?'],
],
[
'actions' => ['logout'],
'allow' => true,
'roles' => ['#'],
],
],
],
];
}

Answer 2

Controller:
public function actions()
{
return [
'error' => [
'class' => 'yii\web\ErrorAction',
],
'captcha' => [
'class' => 'yii\captcha\CaptchaAction',
'fixedVerifyCode' => YII_ENV_TEST ? 'testme' : null,
'foreColor' => 115006,
'backColor' => 333333,
'height' => 30,
'maxLength' => 4,
'minLength' => 4,
'offset' => 2,
'testLimit' => 1,
],
];
}
Model:
public function rules()
{
return [
['verifyCode', 'captcha'],
];
}
View:
use yii\captcha\Captcha;
<?= $form->field($model, 'verifyCode')->widget(Captcha::classname()) ?>

Answer 3

remove this function in site controller and the problems solved:
public function behaviors()
{
return [
'access' => [
'class' => AccessControl::className(),
'rules' => [
[
'actions' => ['login', 'error'],
'allow' => true,
],
[
'actions' => ['logout', 'index'],
'allow' => true,
'roles' => ['#'],
],
],
],
'verbs' => [
'class' => VerbFilter::className(),
'actions' => [
'logout' => ['post'],
],
],
];
}