Merge pull request #3325 from preems/develop

closing  #656 add font_size in create_captcha()
diff --git a/system/helpers/captcha_helper.php b/system/helpers/captcha_helper.php
index 5d023b2..2ffa86d 100644
--- a/system/helpers/captcha_helper.php
+++ b/system/helpers/captcha_helper.php
@@ -71,6 +71,7 @@
 			'font_path'	=> '',
 			'expiration'	=> 7200,
 			'word_length'	=> 8,
+			'font_size'	=> 16,
 			'pool'		=> '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ',
 			'colors'	=> array(
 				'background'	=> array(255,255,255),
@@ -193,13 +194,13 @@
 		$use_font = ($font_path !== '' && file_exists($font_path) && function_exists('imagettftext'));
 		if ($use_font === FALSE)
 		{
-			$font_size = 5;
+			($font_size > 5) && $font_size = 5;
 			$x = mt_rand(0, $img_width / ($length / 3));
 			$y = 0;
 		}
 		else
 		{
-			$font_size = 16;
+			($font_size > 30) && $font_size = 30;
 			$x = mt_rand(0, $img_width / ($length / 1.5));
 			$y = $font_size + 2;
 		}
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index 25f6f2c..242881c 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -133,6 +133,7 @@
       - Added *colors* configuration to allow customization for the *background*, *border*, *text* and *grid* colors.
       - Added *filename* to the returned array elements.
       - Updated to use `imagepng()` in case that `imagejpeg()` isn't available.
+      - Added **font_size** option to allow customization of font size.
 
    -  :doc:`Text Helper <helpers/text_helper>` changes include:
 
diff --git a/user_guide_src/source/helpers/captcha_helper.rst b/user_guide_src/source/helpers/captcha_helper.rst
index 1b74d08..3cf5133 100644
--- a/user_guide_src/source/helpers/captcha_helper.rst
+++ b/user_guide_src/source/helpers/captcha_helper.rst
@@ -33,6 +33,7 @@
 		'img_height'	=> 30,
 		'expiration'	=> 7200,
 		'word_length'	=> 8,
+		'font_size'	=> 16,
 		'pool'		=> '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ',
 
 		// White background and border, black text and red grid
@@ -59,6 +60,7 @@
    in the captcha folder before it will be deleted. The default is two
    hours.
 -  **word_length** defaults to 8, **pool** defaults to '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
+-  **font_size** defaults to 16, the native GD font has a size limit. Specify a "true type" font for bigger sizes. 
 -  If any of the **colors** values is missing, it will be replaced by the default.
 
 Adding a Database