- Qt 6.10
- Third-Party Licenses Used in Qt
- Qt 6.10.2 Reference Documentation

# Third-Party Licenses Used in Qt

Qt includes a number of third-party libraries that are used to provide certain features. Unlike the code described in the code used in Qt document, these libraries are supplied alongside the Qt modules.

Third Party Software may impose additional restrictions and it is the user's responsibility to ensure that they have met the licensing requirements of the GPL, LGPL, or Qt Commercial license and the relevant license of the Third Party Software they are using.

Run `configure -help` to see any options that may be available for controlling the use of these libraries.

## DES (`des.cpp`)

Implementation of DES encryption for NTLM
Copyright 1997-2005 Simon Tatham.
This software is released under the MIT license.

See `src/3rdparty/des/des.cpp` for more information about the terms and conditions under which the code is supplied.

## FreeType 2 (`freetype`) version 2.3.6

The FreeType project is a team of volunteers who develop free, portable and high-quality software solutions for digital typography. We specifically target embedded systems and focus on bringing small, efficient and ubiquitous products. – quoted from `3rdparty/freetype/docs/freetype2.html`.

See `src/3rdparty/freetype/docs/FTL.txt` and `src/3rdparty/freetype/docs/GPL.txt` for license details.

See also the files in `src/3rdparty/harfbuzz`, which are used by FreeType.

Parts of the FreeType projects have been modified and put into Qt for use in the painting subsystem. These files are ftraster.h, ftraster.c, ftgrays.h and ftgrays.c. The following modifications has been made to these files:

- Renamed FT_ and ft_ symbols to QT_FT_ and qt_ft_ to avoid name conflicts.
- Removed parts of code not relevant when compiled with _STANDALONE_ defined.
- Changed behavior in ftraster.c to follow X polygon filling rules.
- Implemented support in ftraster.c for winding / odd even polygon fill rules.
- Replaced bitmap generation with span generation in ftraster.c
- Renamed: ftraster.h to qblackraster_p.h
- Renamed: ftraster.c to qblackraster.c
- Renamed: ftgrays.h to qgrayraster_p.h
- Renamed: ftgrays.c to qgrayraster.c

## HarfBuzz (`harfbuzz`)

This is HarfBuzz, an OpenType Layout engine.

It was derived originally from the OpenType code in FreeType-1.x, ported to FreeType2. (This code has been abandoned for FreeType2, but until something better comes along, should serve our purposes.) In addition to porting to FreeType-2, it has been modified in various other ways. – quoted from `src/3rdparty/harfbuzz/README`.

See `src/3rdparty/harfbuzz/COPYING.FTL` and src/3rdparty/harfbuzz/COPYING.GPL for license details.

## The Independent JPEG Group's JPEG Software (`libjpeg`) version 6b

This package contains C software to implement JPEG image compression and decompression. JPEG (pronounced "jay-peg") is a standardized compression method for full-color and gray-scale images. JPEG is intended for compressing "real-world" scenes; line drawings, cartoons and other non-realistic images are not its strong suit. JPEG is lossy, meaning that the output image is not exactly identical to the input image. – quoted from `src/3rdparty/libjpeg/README`.

See `src/3rdparty/libjpeg/README` for license details.

## MD4 (`md4.cpp` and `md4.h`)

MD4 (RFC-1320) message digest.
Modified from MD5 code by Andrey Panin <pazke@donpac.ru>
Written by Solar Designer <solar@openwall.com> in 2001, and placed in
the public domain. There's absolutely no warranty.

See `src/3rdparty/md4/md4.cpp` and `src/3rdparty/md4/md4.h` for more information about the terms and conditions under which the code is supplied.

## MD5 (`md5.cpp` and `md5.h`)

This code implements the MD5 message-digest algorithm. The algorithm is due to Ron Rivest. This code was written by Colin Plumb in 1993, no copyright is claimed. This code is in the public domain; do with it what you wish. – quoted from `src/3rdparty/md5/md5.h`

See `src/3rdparty/md5/md5.cpp` and `src/3rdparty/md5/md5.h` for more information about the terms and conditions under which the code is supplied.

## MNG Library (`libmng`) version 1.0.10

The libmng library supports decoding, displaying, encoding, and various other manipulations of the Multiple-image Network Graphics (MNG) format image files. It uses the zlib compression library, and optionally the JPEG library by the Independant JPEG Group (IJG) and/or lcms (little cms), a color-management library by Marti Maria Saguer. – quoted from `src/3rdparty/libmng/doc/libmng.txt`

See `src/3rdparty/libmng/LICENSE` for license details.

## PNG Reference Library (`libpng`) version 1.2.29

Libpng was written as a companion to the PNG specification, as a way of reducing the amount of time and effort it takes to support the PNG file format in application programs. – quoted from `src/3rdparty/libpng/libpng.txt`.

See `src/3rdparty/libpng/LICENSE` for license details.

## The ptmalloc memory allocator (`ptmalloc3`) version 1.8

ptmcalloc3 is a scalable concurrent memory allocator suitable for use in multi-threaded programs.

Copyright (c) 2001-2006 Wolfram Gloger

Permission to use, copy, modify, distribute, and sell this software and its documentation for any purpose is hereby granted without fee, provided that (i) the above copyright notices and this permission notice appear in all copies of the software and related documentation, and (ii) the name of Wolfram Gloger may not be used in any advertising or publicity relating to the software.

THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

IN NO EVENT SHALL WOLFRAM GLOGER BE LIABLE FOR ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND, OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

See `src/3rdparty/ptmalloc/COPYRIGHT` for license details.

## SHA-1 (`sha1.cpp`)

Based on the public domain implementation of the SHA-1 algorithm
Copyright (C) Dominik Reichl <dominik.reichl@t-online.de>

See `src/3rdparty/sha1/sha1.cpp` for more information about the terms and conditions under which the code is supplied.

## SQLite (`sqlite`) version 3.5.9

SQLite is a small C library that implements a self-contained, embeddable, zero-configuration SQL database engine. – quoted from www.sqlite.org.

According to the comments in the source files, the code is in the public domain. See the SQLite Copyright page on the SQLite web site for further information.

## TIFF Software Distribution (`libtiff`) version 3.8.2

libtiff is a set of C functions (a library) that support the manipulation of TIFF image files. – quoted from `src/libtiff/html/libtiff.html`

Copyright (c) 1988-1997 Sam Leffler
Copyright (c) 1991-1997 Silicon Graphics, Inc.
Copyright (C) 2004, Andrey Kiselev <dron@ak4719.spb.edu>
Copyright (c) 1997 Greg Ward Larson

Permission to use, copy, modify, distribute, and sell this software and its documentation for any purpose is hereby granted without fee, provided that (i) the above copyright notices and this permission notice appear in all copies of the software and related documentation, and (ii) the names of Sam Leffler and Silicon Graphics may not be used in any advertising or publicity relating to the software without the specific, prior written permission of Sam Leffler and Silicon Graphics.

THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND, OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

Copyright (c) 1996-1997 Sam Leffler
Copyright (c) 1996 Pixar

Permission to use, copy, modify, distribute, and sell this software and its documentation for any purpose is hereby granted without fee, provided that (i) the above copyright notices and this permission notice appear in all copies of the software and related documentation, and (ii) the names of Pixar, Sam Leffler and Silicon Graphics may not be used in any advertising or publicity relating to the software without the specific, prior written permission of Pixar, Sam Leffler and Silicon Graphics.

THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

IN NO EVENT SHALL PIXAR, SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND, OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

See `src/3rdparty/libtiff/COPYRIGHT` for license details.

## Wintab API (`wintab`)

Wintab is a de facto API for pointing devices on Windows. The wintab code is from http://www.pointing.com/WINTAB.HTM.

See `src/3rdparty/wintab/wintab.h` for license details.

## Data Compression Library (`zlib`) version 1.2.3

zlib is a general purpose data compression library. All the code is thread safe. The data format used by the zlib library is described by RFCs (Request for Comments) 1950 to 1952 – quoted from `src/3rdparty/zlib/README`.

See `src/3rdparty/zlib/README` for license details.