From fbde2798688ab99cfe3fdd22746d60f0877b2c27 Mon Sep 17 00:00:00 2001
From: Andrey Andreev <narf@devilix.net>
Date: Mon, 11 May 2015 11:03:06 +0300
Subject: Fix #3846

---
 system/libraries/Image_lib.php      | 18 ++++++++++++------
 user_guide_src/source/changelog.rst |  1 +
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/system/libraries/Image_lib.php b/system/libraries/Image_lib.php
index e056654bb..6374aacdd 100644
--- a/system/libraries/Image_lib.php
+++ b/system/libraries/Image_lib.php
@@ -1055,8 +1055,11 @@ class CI_Image_lib {
 
 		if ($this->rotation_angle === 'hor')
 		{
-			for ($i = 0; $i < $height; $i++, $left = 0, $right = $width-1)
+			for ($i = 0; $i < $height; $i++)
 			{
+				$left = 0;
+				$right = $width - 1;
+
 				while ($left < $right)
 				{
 					$cl = imagecolorat($src_img, $left, $i);
@@ -1072,18 +1075,21 @@ class CI_Image_lib {
 		}
 		else
 		{
-			for ($i = 0; $i < $width; $i++, $top = 0, $bot = $height-1)
+			for ($i = 0; $i < $width; $i++)
 			{
-				while ($top < $bot)
+				$top = 0;
+				$bottom = $height - 1;
+
+				while ($top < $botttom)
 				{
 					$ct = imagecolorat($src_img, $i, $top);
-					$cb = imagecolorat($src_img, $i, $bot);
+					$cb = imagecolorat($src_img, $i, $bottom);
 
 					imagesetpixel($src_img, $i, $top, $cb);
-					imagesetpixel($src_img, $i, $bot, $ct);
+					imagesetpixel($src_img, $i, $bottom, $ct);
 
 					$top++;
-					$bot--;
+					$bottom--;
 				}
 			}
 		}
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index 2d10f8f96..185a17af4 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -27,6 +27,7 @@ Bug fixes for 3.0.1
 -  Fixed a bug (#3801) - :doc:`Output Library <libraries/output>` method ``_display_cache()`` incorrectly looked for the last modified time of a directory instead of the cache file.
 -  Fixed a bug (#3816) - :doc:`Form Validation Library <libraries/form_validation>` treated empty string values as non-existing ones.
 -  Fixed a bug (#3823) - :doc:`Session Library <libraries/sessions>` drivers Redis and Memcached didn't properly handle locks that are blocking the request for more than 30 seconds.
+-  Fixed a bug (#3846) - :doc:`Image Manipulation Library <libraries/image_lib>` method `image_mirror_gd()` didn't properly initialize its variables.
 
 Version 3.0.0
 =============
-- 
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