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 qt-everywhere-src-5.15.16/qtbase/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
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     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
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     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
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 form) with the major components (compiler, kernel, and so on) of the
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 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
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 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 ---