I. Overview

Zlib and libpngare two libraries with regard to the PNG (Portable Network Graphics) sourcecode. Jean-loup Gailly wrote the compression part of zilb and Mark Adler was incharge of the decompression part. Libpng were written by Guy Eric Schalnat, AndreasDilger and Glenn Randers-Pehrson. Since in practice, the two softwares mustcoexist in order to function well, they are often combined and co-licensed under the zlib/libpng.

 

II. Current Status

Almost all the PNG softwares are licensed under zlib/libpng.

III. Rights and Duties

  1. Rights

Permission is granted to anyone to use this software for any purpose, including commercial applications, and to alter it and redistribute it freely.

  2. Duties

    (1) The origin of this software must not be misrepresented; the licensee must not claim that he/she wrote the original software.

    (2) Altered source versions must clearly indicate the origin of the source code.

    (3) This notice may not be removed or altered from any source distribution. In other words, it does not grant the right to alter the license.

IV. Other Important Features

Zlib/libpng is a free software license approved by the Free Software Foundation (FSF), and is also an open source license approved by the Open Source Initiative (OSI). It is compatible with the GPL.