From d211a02b3c636e19d6029700acb42c7a47da3dbc Mon Sep 17 00:00:00 2001
From: giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8>
Date: Mon, 26 Sep 2016 16:47:30 +0000
Subject: Add comment

git-svn-id: http://svn.code.sf.net/p/netpbm/code/trunk@2822 9d0c8265-081b-0410-96cb-a4ca84ce46f8
---
 converter/other/pngx.h | 4 ++++
 1 file changed, 4 insertions(+)

(limited to 'converter')

diff --git a/converter/other/pngx.h b/converter/other/pngx.h
index cabb0663..008081eb 100644
--- a/converter/other/pngx.h
+++ b/converter/other/pngx.h
@@ -2,6 +2,10 @@
 #define PNGX_H_INCLUDED
 
 #include <png.h>
+    /* This includes the Zlib interface header file zlib.h because libpng uses
+       libz and some of the Zlib interface, e.g. the Z_DEFLATED constant,
+       is part of the libpng interface.
+    */
 #include "pm_c_util.h"
 
 /* pngx is designed to be an extension of the PNG library to make using
-- 
cgit 1.4.1