VisualStudio instructions libpng version 1.4.19beta02 - December 13, 2015 Copyright (c) 1998-2010 Glenn Randers-Pehrson This code is released under the libpng license. For conditions of distribution and use, see the disclaimer and license in png.h This directory contains support for building libpng under MicroSoft VisualStudio 2010. It may also work under later versions of VisualStudio. You should be familiar with VisualStudio before using this directory. This is a slightly modified copy of the 'vstudio' solution from libpng 1.5; it is intended to provide compatibility for libpng 1.4 with later releases of zlib (from 1.2.4) and to provide a migration aid for 1.5. A 'VB' DLL is no longer produced - use the standard 'Release' DLL. Initial preparations ==================== You should install the 'official' build of zlib on your system - follow the instructions provided on http://www.zlib.net. When a new release is being made of zlib the instructions disappear for a while until the new official build is available. You will have to wait. You must enter some information in zlib.props before attempting to build with this 'solution'. Please read and edit zlib.props first. You will probably not be familiar with the contents of zlib.props - do not worry, it is mostly harmless. Make sure that your official build layout matches the requirements listed in zlib.props. Prior to zlib-1.2.4 the official build (1.2.3) placed include and library files in different directories - if you find this has happened just put them all in the same directory. This is all you need to do to build the 'release' and 'release library' configurations. Debugging ========= The release configurations default to /Ox optimization. Full debugging information is produced (in the .pdb), but if you encounter a problem the optimization may make it difficult to debug. Simply rebuild with a lower optimization level (e.g. /Od.) Stop reading here ================= You have enough information to build a working application. Debug versions have limited support =================================== This solution includes limited support for debug versions of libpng. You do not need these unless your own solution itself uses debug builds (it is far more effective to debug on the release builds, there is no point building a special debug build.) If, despite the previous paragraph, you still feel you need a debug build you will have to download the zlib source as well (http://www.zlib.net) and include the directory where you unpack it in zlib.props. This solution will then be able to build a minimal zlib sufficient for libpng. This build is only suitable for making a debug libpng. The debug build of libpng is minimally supported. Support for debug builds of zlib is also minimal. You really don't want to do this. This solution only supports the Multi-Threaded DLL C Runtime ============================================================ If you examine the solution you will find that it very deliberately lists exactly which MicroSoft DLLs it is linking against. It explicitly links against msvcrt.lib. The debug version links against msvcrtd.lib (this is why it is a debug version - it's nothing to do with having any special debug support, it doesn't). These versions of the MicroSoft C runtime correspond to the compiler flags /MD (release) and /MDd (debug) - the "Multi-Threaded DLL" implementation of the C runtime library. If you need to change this then you will have to make sure that both the compiler flags and the ".lib" in the linker dependences match up. Fortunately neither zlib nor libpng require libraries other than a C runtime and kernel32. You cannot pass (FILE*) objects from a different runtime (including msvcrtd to msvcrt) to libpng. If you do then your program will crash within libpng when it first makes a file read or write call. It is likely if you have read this far that you have found you can't avoid having multiple C runtimes in your program. This is OK, it does work, but you will have to implement the libpng file read/write callbacks rather than using the internal libpng default. This is easy.