- Qt 6.10
- Qt GUI
- LibPNG, version 1.6.56
- Qt 6.10.3 Reference Documentation

# LibPNG, version 1.6.56

libpng is the official PNG reference library.

Used in the qpng image plugin. Configure with -system-libpng or -no-libpng to avoid.

The sources can be found in qtbase/src/3rdparty/libpng.

Project Homepage, upstream version: 1.6.56

     Copyright (c) 1995-2026 The PNG Reference Library Authors
     Copyright (c) 2000-2026 Cosmin Truta
     Copyright (c) 1998-2018 Glenn Randers-Pehrson
     Copyright (c) 1996-1997 Andreas Dilger
     Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
     Copyright (c) 2000-2017 Simon-Pierre Cadieux
     Copyright (c) 2000-2017 Eric S. Raymond
     Copyright (c) 2000-2017 Mans Rullgard
     Copyright (c) 2000-2017 Gilles Vollant
     Copyright (c) 2000-2017 James Yu
     Copyright (c) 2000-2017 Mandar Sahastrabuddhe
     Copyright (c) 1998-2000 Tom Lane
     Copyright (c) 1998-2000 Willem van Schaik
     Copyright (c) 1996-1997 John Bowler
     Copyright (c) 1996-1997 Kevin Bracey
     Copyright (c) 1996-1997 Sam Bushell
     Copyright (c) 1996-1997 Magnus Holmgren
     Copyright (c) 1996-1997 Greg Roelofs
     Copyright (c) 1996-1997 Tom Tanner
     Copyright (c) 1995-1996 Dave Martindale
     Copyright (c) 1995-1996 Paul Schmidt
     Copyright (c) 1995-1996 Tim Wegner

libpng License and PNG Reference Library version 2.

     COPYRIGHT NOTICE, DISCLAIMER, and LICENSE
     =========================================

     PNG Reference Library License version 2
     ---------------------------------------

      * Copyright (c) 1995-2026 The PNG Reference Library Authors.
      * Copyright (c) 2018-2026 Cosmin Truta.
      * Copyright (c) 2000-2002, 2004, 2006-2018 Glenn Randers-Pehrson.
      * Copyright (c) 1996-1997 Andreas Dilger.
      * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.

     The software is supplied "as is", without warranty of any kind,
     express or implied, including, without limitation, the warranties
     of merchantability, fitness for a particular purpose, title, and
     non-infringement.  In no event shall the Copyright owners, or
     anyone distributing the software, be liable for any damages or
     other liability, whether in contract, tort or otherwise, arising
     from, out of, or in connection with the software, or the use or
     other dealings in the software, even if advised of the possibility
     of such damage.

     Permission is hereby granted to use, copy, modify, and distribute
     this software, or portions hereof, for any purpose, without fee,
     subject to the following restrictions:

      1. The origin of this software must not be misrepresented; you
         must not claim that you wrote the original software.  If you
         use this software in a product, an acknowledgment in the product
         documentation would be appreciated, but is not required.

      2. Altered source versions must be plainly marked as such, and must
         not be misrepresented as being the original software.

      3. This Copyright notice may not be removed or altered from any
         source or altered source distribution.

     PNG Reference Library License version 1 (for libpng 0.5 through 1.6.35)
     -----------------------------------------------------------------------

     libpng versions 1.0.7, July 1, 2000, through 1.6.35, July 15, 2018 are
     Copyright (c) 2000-2002, 2004, 2006-2018 Glenn Randers-Pehrson, are
     derived from libpng-1.0.6, and are distributed according to the same
     disclaimer and license as libpng-1.0.6 with the following individuals
     added to the list of Contributing Authors:

         Simon-Pierre Cadieux
         Eric S. Raymond
         Mans Rullgard
         Cosmin Truta
         Gilles Vollant
         James Yu
         Mandar Sahastrabuddhe
         Google Inc.
         Vadim Barkov

     and with the following additions to the disclaimer:

         There is no warranty against interference with your enjoyment of
         the library or against infringement.  There is no warranty that our
         efforts or the library will fulfill any of your particular purposes
         or needs.  This library is provided with all faults, and the entire
         risk of satisfactory quality, performance, accuracy, and effort is
         with the user.

     Some files in the "contrib" directory and some configure-generated
     files that are distributed with libpng have other copyright owners, and
     are released under other open source licenses.

     libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
     Copyright (c) 1998-2000 Glenn Randers-Pehrson, are derived from
     libpng-0.96, and are distributed according to the same disclaimer and
     license as libpng-0.96, with the following individuals added to the
     list of Contributing Authors:

         Tom Lane
         Glenn Randers-Pehrson
         Willem van Schaik

     libpng versions 0.89, June 1996, through 0.96, May 1997, are
     Copyright (c) 1996-1997 Andreas Dilger, are derived from libpng-0.88,
     and are distributed according to the same disclaimer and license as
     libpng-0.88, with the following individuals added to the list of
     Contributing Authors:

         John Bowler
         Kevin Bracey
         Sam Bushell
         Magnus Holmgren
         Greg Roelofs
         Tom Tanner

     Some files in the "scripts" directory have other copyright owners,
     but are released under this license.

     libpng versions 0.5, May 1995, through 0.88, January 1996, are
     Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.

     For the purposes of this copyright and license, "Contributing Authors"
     is defined as the following set of individuals:

         Andreas Dilger
         Dave Martindale
         Guy Eric Schalnat
         Paul Schmidt
         Tim Wegner

     The PNG Reference Library is supplied "AS IS".  The Contributing
     Authors and Group 42, Inc. disclaim all warranties, expressed or
     implied, including, without limitation, the warranties of
     merchantability and of fitness for any purpose.  The Contributing
     Authors and Group 42, Inc. assume no liability for direct, indirect,
     incidental, special, exemplary, or consequential damages, which may
     result from the use of the PNG Reference Library, even if advised of
     the possibility of such damage.

     Permission is hereby granted to use, copy, modify, and distribute this
     source code, or portions hereof, for any purpose, without fee, subject
     to the following restrictions:

      1. The origin of this source code must not be misrepresented.

      2. Altered versions must be plainly marked as such and must not
         be misrepresented as being the original source.

      3. This Copyright notice may not be removed or altered from any
         source or altered source distribution.

     The Contributing Authors and Group 42, Inc. specifically permit,
     without fee, and encourage the use of this source code as a component
     to supporting the PNG file format in commercial products.  If you use
     this source code in a product, acknowledgment is not required but would
     be appreciated.