Fixes #5598: added ImageMagick with PNG and GD with FreeType checks to requirements of basic and advanced applications, used better Captcha exception message

requirements.php

@@ -23,6 +23,28 @@ if (!is_dir($frameworkPath)) {
 require_once($frameworkPath . '/requirements/YiiRequirementChecker.php');
 $requirementsChecker = new YiiRequirementChecker();
 
+$gdMemo = $imagickMemo = 'Either GD PHP extension with FreeType support or ImageMagick PHP extension with PNG support is required for image CAPTCHA.';
+$gdOK = $imagickOK = false;
+
+if (extension_loaded('imagick')) {
+    $imagick = new Imagick();
+    $imagickFormats = $imagick->queryFormats('PNG');
+    if (in_array('PNG', $imagickFormats)) {
+        $imagickOK = true;
+    } else {
+        $imagickMemo = 'Imagick extension should be installed with PNG support in order to be used for image CAPTCHA.';
+    }
+}
+
+if (extension_loaded('gd')) {
+    $gdInfo = gd_info();
+    if (!empty($gdInfo['FreeType Support'])) {
+        $gdOK = true;
+    } else {
+        $gdMemo = 'GD extension should be installed with FreeType support in order to be used for image CAPTCHA.';
+    }
+}
+
 /**
  * Adjust requirements according to your application specifics.
  */
@@ -69,6 +91,21 @@ $requirements = array(
         'condition' => extension_loaded('apc'),
         'by' => '<a href="http://www.yiiframework.com/doc-2.0/yii-caching-apccache.html">ApcCache</a>',
     ),
+    // CAPTCHA:
+    array(
+        'name' => 'GD PHP extension with FreeType support',
+        'mandatory' => false,
+        'condition' => $gdOK,
+        'by' => '<a href="http://www.yiiframework.com/doc-2.0/yii-captcha-captcha.html">Captcha</a>',
+        'memo' => $gdMemo,
+    ),
+    array(
+        'name' => 'ImageMagick PHP extension with PNG support',
+        'mandatory' => false,
+        'condition' => $imagickOK,
+        'by' => '<a href="http://www.yiiframework.com/doc-2.0/yii-captcha-captcha.html">Captcha</a>',
+        'memo' => $imagickMemo,
+    ),
     // PHP ini :
     'phpSafeMode' => array(
         'name' => 'PHP safe mode',