From d3fd15d76b2e0be55c6fe454875a1114aa8a3f24 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=BC=A0=E5=9E=9A?= <yaozhang.chn@gmail.com>
Date: Fri, 29 Jul 2016 12:45:58 +0800
Subject: [PATCH] fix memory leak bug (#13)

* fixed memory leak bug

* fix memory leak bug
---
 captcha/image.py | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/captcha/image.py b/captcha/image.py
index 3741c02..3a5c80f 100644
--- a/captcha/image.py
+++ b/captcha/image.py
@@ -30,6 +30,10 @@ else:
     __all__ = ['ImageCaptcha']
 
 
+table  =  []
+for  i  in  range( 256 ):
+    table.append( i * 1.97 )
+  
 class _Captcha(object):
     def generate(self, chars, format='png'):
         """Generate an Image Captcha of the given characters.
@@ -202,7 +206,7 @@ class ImageCaptcha(_Captcha):
 
         for im in images:
             w, h = im.size
-            mask = im.convert('L').point(lambda i: i * 1.97)
+            mask = im.convert('L').point(table)
             image.paste(im, (offset, int((self._height - h) / 2)), mask)
             offset = offset + w + random.randint(-rand, 0)