- Qt 6.10
- Qt GUI
- Anti-aliasing rasterizer from FreeType 2
- Qt 6.10.2 Reference Documentation

# Anti-aliasing rasterizer from FreeType 2

FreeType is a freely available software library to render fonts.

Used in Qt GUI.

The sources can be found in qt6-base-6.10.2+dfsg/src/gui/painting/qgrayraster.c.

Project Homepage

     Copyright 2000-2016 by David Turner, Robert Wilhelm, and Werner Lemberg.

Freetype Project License or GNU General Public License v2.0 only.

     FREETYPE LICENSES
     -----------------

     The FreeType  2 font  engine is  copyrighted work  and cannot  be used
     legally without  a software  license.  In order  to make  this project
     usable to  a vast majority of  developers, we distribute it  under two
     mutually exclusive open-source licenses.

     This means that *you* must choose  *one* of the two licenses described
     below, then obey all its terms and conditions when using FreeType 2 in
     any of your projects or products.

       - The FreeType License,  found in the file  `docs/FTL.TXT`, which is
         similar to the  original BSD license *with*  an advertising clause
         that forces  you to explicitly  cite the FreeType project  in your
         product's  documentation.  All  details are  in the  license file.
         This license is suited to products which don't use the GNU General
         Public License.

         Note that  this license  is compatible to  the GNU  General Public
         License version 3, but not version 2.

       - The   GNU   General   Public   License   version   2,   found   in
         `docs/GPLv2.TXT`  (any  later  version  can  be  used  also),  for
         programs  which  already  use  the  GPL.  Note  that  the  FTL  is
         incompatible with GPLv2 due to its advertisement clause.

     The contributed  BDF and PCF  drivers come  with a license  similar to
     that  of the  X Window  System.   It is  compatible to  the above  two
     licenses (see files `src/bdf/README`  and `src/pcf/README`).  The same
     holds   for   the   source    code   files   `src/base/fthash.c`   and
     `include/freetype/internal/fthash.h`; they wer part  of the BDF driver
     in earlier FreeType versions.

     The gzip  module uses the  zlib license (see  `src/gzip/zlib.h`) which
     too is compatible to the above two licenses.

     The  MD5 checksum  support  (only used  for  debugging in  development
     builds) is in the public domain.

     -- FTL.TXT --

     The FreeType Project LICENSE
     ----------------------------

             2006-Jan-27

     Copyright 1996-2002, 2006 by
     David Turner, Robert Wilhelm, and Werner Lemberg

     Introduction
     ============

     The FreeType  Project is distributed in  several archive packages;
     some of them may contain, in addition to the FreeType font engine,
     various tools and  contributions which rely on, or  relate to, the
     FreeType Project.

     This  license applies  to all  files found  in such  packages, and
     which do not  fall under their own explicit  license.  The license
     affects  thus  the  FreeType   font  engine,  the  test  programs,
     documentation and makefiles, at the very least.

     This  license   was  inspired  by  the  BSD,   Artistic,  and  IJG
     (Independent JPEG  Group) licenses, which  all encourage inclusion
     and  use of  free  software in  commercial  and freeware  products
     alike.  As a consequence, its main points are that:

     o We don't promise that this software works. However, we will be
     interested in any kind of bug reports. (`as is' distribution)

     o You can  use this software for whatever you  want, in parts or
     full form, without having to pay us. (`royalty-free' usage)

     o You may not pretend that  you wrote this software.  If you use
     it, or  only parts of it,  in a program,  you must acknowledge
     somewhere  in  your  documentation  that  you  have  used  the
     FreeType code. (`credits')

     We  specifically  permit  and  encourage  the  inclusion  of  this
     software, with  or without modifications,  in commercial products.
     We  disclaim  all warranties  covering  The  FreeType Project  and
     assume no liability related to The FreeType Project.

     Finally,  many  people  asked  us  for  a  preferred  form  for  a
     credit/disclaimer to use in compliance with this license.  We thus
     encourage you to use the following text:

     """
     Portions of this software are copyright © <year> The FreeType
     Project (www.freetype.org).  All rights reserved.
     """

     Please replace <year> with the value from the FreeType version you
     actually use.

     Legal Terms
     ===========

     0. Definitions
     --------------

     Throughout this license,  the terms `package', `FreeType Project',
     and  `FreeType  archive' refer  to  the  set  of files  originally
     distributed  by the  authors  (David Turner,  Robert Wilhelm,  and
     Werner Lemberg) as the `FreeType Project', be they named as alpha,
     beta or final release.

     `You' refers to  the licensee, or person using  the project, where
     `using' is a generic term including compiling the project's source
     code as  well as linking it  to form a  `program' or `executable'.
     This  program is  referred to  as  `a program  using the  FreeType
     engine'.

     This  license applies  to all  files distributed  in  the original
     FreeType  Project,   including  all  source   code,  binaries  and
     documentation,  unless  otherwise  stated   in  the  file  in  its
     original, unmodified form as  distributed in the original archive.
     If you are  unsure whether or not a particular  file is covered by
     this license, you must contact us to verify this.

     The FreeType  Project is copyright (C) 1996-2000  by David Turner,
     Robert Wilhelm, and Werner Lemberg.  All rights reserved except as
     specified below.

     1. No Warranty
     --------------

     THE FREETYPE PROJECT  IS PROVIDED `AS IS' WITHOUT  WARRANTY OF ANY
     KIND, EITHER  EXPRESS OR IMPLIED,  INCLUDING, BUT NOT  LIMITED TO,
     WARRANTIES  OF  MERCHANTABILITY   AND  FITNESS  FOR  A  PARTICULAR
     PURPOSE.  IN NO EVENT WILL ANY OF THE AUTHORS OR COPYRIGHT HOLDERS
     BE LIABLE  FOR ANY DAMAGES CAUSED  BY THE USE OR  THE INABILITY TO
     USE, OF THE FREETYPE PROJECT.

     2. Redistribution
     -----------------

     This  license  grants  a  worldwide, royalty-free,  perpetual  and
     irrevocable right  and license to use,  execute, perform, compile,
     display,  copy,   create  derivative  works   of,  distribute  and
     sublicense the  FreeType Project (in  both source and  object code
     forms)  and  derivative works  thereof  for  any  purpose; and  to
     authorize others  to exercise  some or all  of the  rights granted
     herein, subject to the following conditions:

     o Redistribution of  source code  must retain this  license file
     (`FTL.TXT') unaltered; any  additions, deletions or changes to
     the original  files must be clearly  indicated in accompanying
     documentation.   The  copyright   notices  of  the  unaltered,
     original  files must  be  preserved in  all  copies of  source
     files.

     o Redistribution in binary form must provide a  disclaimer  that
     states  that  the software is based in part of the work of the
     FreeType Team,  in  the  distribution  documentation.  We also
     encourage you to put an URL to the FreeType web page  in  your
     documentation, though this isn't mandatory.

     These conditions  apply to any  software derived from or  based on
     the FreeType Project,  not just the unmodified files.   If you use
     our work, you  must acknowledge us.  However, no  fee need be paid
     to us.

     3. Advertising
     --------------

     Neither the  FreeType authors and  contributors nor you  shall use
     the name of the  other for commercial, advertising, or promotional
     purposes without specific prior written permission.

     We suggest,  but do not require, that  you use one or  more of the
     following phrases to refer  to this software in your documentation
     or advertising  materials: `FreeType Project',  `FreeType Engine',
     `FreeType library', or `FreeType Distribution'.

     As  you have  not signed  this license,  you are  not  required to
     accept  it.   However,  as  the FreeType  Project  is  copyrighted
     material, only  this license, or  another one contracted  with the
     authors, grants you  the right to use, distribute,  and modify it.
     Therefore,  by  using,  distributing,  or modifying  the  FreeType
     Project, you indicate that you understand and accept all the terms
     of this license.

     4. Contacts
     -----------

     There are two mailing lists related to FreeType:

     o freetype@nongnu.org

     Discusses general use and applications of FreeType, as well as
     future and  wanted additions to the  library and distribution.
     If  you are looking  for support,  start in  this list  if you
     haven't found anything to help you in the documentation.

     o freetype-devel@nongnu.org

     Discusses bugs,  as well  as engine internals,  design issues,
     specific licenses, porting, etc.

     Our home page can be found at

     https://www.freetype.org

     --- end of FTL.TXT ---

     --- GPLv2.TXT ---

                         GNU GENERAL PUBLIC LICENSE
                            Version 2, June 1991

      Copyright (C) 1989, 1991 Free Software Foundation, Inc.
          51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
      Everyone is permitted to copy and distribute verbatim copies
      of this license document, but changing it is not allowed.

                                 Preamble

       The licenses for most software are designed to take away your
     freedom to share and change it.  By contrast, the GNU General Public
     License is intended to guarantee your freedom to share and change free
     software--to make sure the software is free for all its users.  This
     General Public License applies to most of the Free Software
     Foundation's software and to any other program whose authors commit to
     using it.  (Some other Free Software Foundation software is covered by
     the GNU Library General Public License instead.)  You can apply it to
     your programs, too.

       When we speak of free software, we are referring to freedom, not
     price.  Our General Public Licenses are designed to make sure that you
     have the freedom to distribute copies of free software (and charge for
     this service if you wish), that you receive source code or can get it
     if you want it, that you can change the software or use pieces of it
     in new free programs; and that you know you can do these things.

       To protect your rights, we need to make restrictions that forbid
     anyone to deny you these rights or to ask you to surrender the rights.
     These restrictions translate to certain responsibilities for you if you
     distribute copies of the software, or if you modify it.

       For example, if you distribute copies of such a program, whether
     gratis or for a fee, you must give the recipients all the rights that
     you have.  You must make sure that they, too, receive or can get the
     source code.  And you must show them these terms so they know their
     rights.

       We protect your rights with two steps: (1) copyright the software, and
     (2) offer you this license which gives you legal permission to copy,
     distribute and/or modify the software.

       Also, for each author's protection and ours, we want to make certain
     that everyone understands that there is no warranty for this free
     software.  If the software is modified by someone else and passed on, we
     want its recipients to know that what they have is not the original, so
     that any problems introduced by others will not reflect on the original
     authors' reputations.

       Finally, any free program is threatened constantly by software
     patents.  We wish to avoid the danger that redistributors of a free
     program will individually obtain patent licenses, in effect making the
     program proprietary.  To prevent this, we have made it clear that any
     patent must be licensed for everyone's free use or not licensed at all.

       The precise terms and conditions for copying, distribution and
     modification follow.

                         GNU GENERAL PUBLIC LICENSE
        TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

       0. This License applies to any program or other work which contains
     a notice placed by the copyright holder saying it may be distributed
     under the terms of this General Public License.  The "Program", below,
     refers to any such program or work, and a "work based on the Program"
     means either the Program or any derivative work under copyright law:
     that is to say, a work containing the Program or a portion of it,
     either verbatim or with modifications and/or translated into another
     language.  (Hereinafter, translation is included without limitation in
     the term "modification".)  Each licensee is addressed as "you".

     Activities other than copying, distribution and modification are not
     covered by this License; they are outside its scope.  The act of
     running the Program is not restricted, and the output from the Program
     is covered only if its contents constitute a work based on the
     Program (independent of having been made by running the Program).
     Whether that is true depends on what the Program does.

       1. You may copy and distribute verbatim copies of the Program's
     source code as you receive it, in any medium, provided that you
     conspicuously and appropriately publish on each copy an appropriate
     copyright notice and disclaimer of warranty; keep intact all the
     notices that refer to this License and to the absence of any warranty;
     and give any other recipients of the Program a copy of this License
     along with the Program.

     You may charge a fee for the physical act of transferring a copy, and
     you may at your option offer warranty protection in exchange for a fee.

       2. You may modify your copy or copies of the Program or any portion
     of it, thus forming a work based on the Program, and copy and
     distribute such modifications or work under the terms of Section 1
     above, provided that you also meet all of these conditions:

         a) You must cause the modified files to carry prominent notices
         stating that you changed the files and the date of any change.

         b) You must cause any work that you distribute or publish, that in
         whole or in part contains or is derived from the Program or any
         part thereof, to be licensed as a whole at no charge to all third
         parties under the terms of this License.

         c) If the modified program normally reads commands interactively
         when run, you must cause it, when started running for such
         interactive use in the most ordinary way, to print or display an
         announcement including an appropriate copyright notice and a
         notice that there is no warranty (or else, saying that you provide
         a warranty) and that users may redistribute the program under
         these conditions, and telling the user how to view a copy of this
         License.  (Exception: if the Program itself is interactive but
         does not normally print such an announcement, your work based on
         the Program is not required to print an announcement.)

     These requirements apply to the modified work as a whole.  If
     identifiable sections of that work are not derived from the Program,
     and can be reasonably considered independent and separate works in
     themselves, then this License, and its terms, do not apply to those
     sections when you distribute them as separate works.  But when you
     distribute the same sections as part of a whole which is a work based
     on the Program, the distribution of the whole must be on the terms of
     this License, whose permissions for other licensees extend to the
     entire whole, and thus to each and every part regardless of who wrote it.

     Thus, it is not the intent of this section to claim rights or contest
     your rights to work written entirely by you; rather, the intent is to
     exercise the right to control the distribution of derivative or
     collective works based on the Program.

     In addition, mere aggregation of another work not based on the Program
     with the Program (or with a work based on the Program) on a volume of
     a storage or distribution medium does not bring the other work under
     the scope of this License.

       3. You may copy and distribute the Program (or a work based on it,
     under Section 2) in object code or executable form under the terms of
     Sections 1 and 2 above provided that you also do one of the following:

         a) Accompany it with the complete corresponding machine-readable
         source code, which must be distributed under the terms of Sections
         1 and 2 above on a medium customarily used for software interchange; or,

         b) Accompany it with a written offer, valid for at least three
         years, to give any third party, for a charge no more than your
         cost of physically performing source distribution, a complete
         machine-readable copy of the corresponding source code, to be
         distributed under the terms of Sections 1 and 2 above on a medium
         customarily used for software interchange; or,

         c) Accompany it with the information you received as to the offer
         to distribute corresponding source code.  (This alternative is
         allowed only for noncommercial distribution and only if you
         received the program in object code or executable form with such
         an offer, in accord with Subsection b above.)

     The source code for a work means the preferred form of the work for
     making modifications to it.  For an executable work, complete source
     code means all the source code for all modules it contains, plus any
     associated interface definition files, plus the scripts used to
     control compilation and installation of the executable.  However, as a
     special exception, the source code distributed need not include
     anything that is normally distributed (in either source or binary
     form) with the major components (compiler, kernel, and so on) of the
     operating system on which the executable runs, unless that component
     itself accompanies the executable.

     If distribution of executable or object code is made by offering
     access to copy from a designated place, then offering equivalent
     access to copy the source code from the same place counts as
     distribution of the source code, even though third parties are not
     compelled to copy the source along with the object code.

       4. You may not copy, modify, sublicense, or distribute the Program
     except as expressly provided under this License.  Any attempt
     otherwise to copy, modify, sublicense or distribute the Program is
     void, and will automatically terminate your rights under this License.
     However, parties who have received copies, or rights, from you under
     this License will not have their licenses terminated so long as such
     parties remain in full compliance.

       5. You are not required to accept this License, since you have not
     signed it.  However, nothing else grants you permission to modify or
     distribute the Program or its derivative works.  These actions are
     prohibited by law if you do not accept this License.  Therefore, by
     modifying or distributing the Program (or any work based on the
     Program), you indicate your acceptance of this License to do so, and
     all its terms and conditions for copying, distributing or modifying
     the Program or works based on it.

       6. Each time you redistribute the Program (or any work based on the
     Program), the recipient automatically receives a license from the
     original licensor to copy, distribute or modify the Program subject to
     these terms and conditions.  You may not impose any further
     restrictions on the recipients' exercise of the rights granted herein.
     You are not responsible for enforcing compliance by third parties to
     this License.

       7. If, as a consequence of a court judgment or allegation of patent
     infringement or for any other reason (not limited to patent issues),
     conditions are imposed on you (whether by court order, agreement or
     otherwise) that contradict the conditions of this License, they do not
     excuse you from the conditions of this License.  If you cannot
     distribute so as to satisfy simultaneously your obligations under this
     License and any other pertinent obligations, then as a consequence you
     may not distribute the Program at all.  For example, if a patent
     license would not permit royalty-free redistribution of the Program by
     all those who receive copies directly or indirectly through you, then
     the only way you could satisfy both it and this License would be to
     refrain entirely from distribution of the Program.

     If any portion of this section is held invalid or unenforceable under
     any particular circumstance, the balance of the section is intended to
     apply and the section as a whole is intended to apply in other
     circumstances.

     It is not the purpose of this section to induce you to infringe any
     patents or other property right claims or to contest validity of any
     such claims; this section has the sole purpose of protecting the
     integrity of the free software distribution system, which is
     implemented by public license practices.  Many people have made
     generous contributions to the wide range of software distributed
     through that system in reliance on consistent application of that
     system; it is up to the author/donor to decide if he or she is willing
     to distribute software through any other system and a licensee cannot
     impose that choice.

     This section is intended to make thoroughly clear what is believed to
     be a consequence of the rest of this License.

       8. If the distribution and/or use of the Program is restricted in
     certain countries either by patents or by copyrighted interfaces, the
     original copyright holder who places the Program under this License
     may add an explicit geographical distribution limitation excluding
     those countries, so that distribution is permitted only in or among
     countries not thus excluded.  In such case, this License incorporates
     the limitation as if written in the body of this License.

       9. The Free Software Foundation may publish revised and/or new versions
     of the General Public License from time to time.  Such new versions will
     be similar in spirit to the present version, but may differ in detail to
     address new problems or concerns.

     Each version is given a distinguishing version number.  If the Program
     specifies a version number of this License which applies to it and "any
     later version", you have the option of following the terms and conditions
     either of that version or of any later version published by the Free
     Software Foundation.  If the Program does not specify a version number of
     this License, you may choose any version ever published by the Free Software
     Foundation.

       10. If you wish to incorporate parts of the Program into other free
     programs whose distribution conditions are different, write to the author
     to ask for permission.  For software which is copyrighted by the Free
     Software Foundation, write to the Free Software Foundation; we sometimes
     make exceptions for this.  Our decision will be guided by the two goals
     of preserving the free status of all derivatives of our free software and
     of promoting the sharing and reuse of software generally.

                                 NO WARRANTY

       11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
     FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
     OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
     PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
     OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
     TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
     PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
     REPAIR OR CORRECTION.

       12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
     WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
     REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
     INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
     OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
     TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
     YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
     PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
     POSSIBILITY OF SUCH DAMAGES.

                          END OF TERMS AND CONDITIONS

                 How to Apply These Terms to Your New Programs

       If you develop a new program, and you want it to be of the greatest
     possible use to the public, the best way to achieve this is to make it
     free software which everyone can redistribute and change under these terms.

       To do so, attach the following notices to the program.  It is safest
     to attach them to the start of each source file to most effectively
     convey the exclusion of warranty; and each file should have at least
     the "copyright" line and a pointer to where the full notice is found.

         <one line to give the program's name and a brief idea of what it does.>
         Copyright (C) <year>  <name of author>

         This program is free software; you can redistribute it and/or modify
         it under the terms of the GNU General Public License as published by
         the Free Software Foundation; either version 2 of the License, or
         (at your option) any later version.

         This program is distributed in the hope that it will be useful,
         but WITHOUT ANY WARRANTY; without even the implied warranty of
         MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
         GNU General Public License for more details.

         You should have received a copy of the GNU General Public License
         along with this program; if not, write to the Free Software
         Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

     Also add information on how to contact you by electronic and paper mail.

     If the program is interactive, make it output a short notice like this
     when it starts in an interactive mode:

         Gnomovision version 69, Copyright (C) year  name of author
         Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
         This is free software, and you are welcome to redistribute it
         under certain conditions; type `show c' for details.

     The hypothetical commands `show w' and `show c' should show the appropriate
     parts of the General Public License.  Of course, the commands you use may
     be called something other than `show w' and `show c'; they could even be
     mouse-clicks or menu items--whatever suits your program.

     You should also get your employer (if you work as a programmer) or your
     school, if any, to sign a "copyright disclaimer" for the program, if
     necessary.  Here is a sample; alter the names:

       Yoyodyne, Inc., hereby disclaims all copyright interest in the program
       `Gnomovision' (which makes passes at compilers) written by James Hacker.

       <signature of Ty Coon>, 1 April 1989
       Ty Coon, President of Vice

     This General Public License does not permit incorporating your program into
     proprietary programs.  If your program is a subroutine library, you may
     consider it more useful to permit linking proprietary applications with the
     library.  If this is what you want to do, use the GNU Library General
     Public License instead of this License.

     --- end of GPLv2.TXT ---