- Qt 6.9
- Qt PDF
- Qt PDF Licensing
- libjpeg-turbo
- Qt 6.9.1 Reference Documentation

# libjpeg-turbo

Project Homepage

     libjpeg-turbo Licenses
     ======================

     libjpeg-turbo is covered by three compatible BSD-style open source licenses:

     - The IJG (Independent JPEG Group) License, which is listed in
       [README.ijg](README.ijg)

       This license applies to the libjpeg API library and associated programs
       (any code inherited from libjpeg, and any modifications to that code.)

     - The Modified (3-clause) BSD License, which is listed below

       This license covers the TurboJPEG API library and associated programs, as
       well as the build system.

     - The [zlib License](https://opensource.org/licenses/Zlib)

       This license is a subset of the other two, and it covers the libjpeg-turbo
       SIMD extensions.

     Complying with the libjpeg-turbo Licenses
     =========================================

     This section provides a roll-up of the libjpeg-turbo licensing terms, to the
     best of our understanding.

     1.  If you are distributing a modified version of the libjpeg-turbo source,
         then:

         1.  You cannot alter or remove any existing copyright or license notices
             from the source.

             **Origin**
             - Clause 1 of the IJG License
             - Clause 1 of the Modified BSD License
             - Clauses 1 and 3 of the zlib License

         2.  You must add your own copyright notice to the header of each source
             file you modified, so others can tell that you modified that file (if
             there is not an existing copyright header in that file, then you can
             simply add a notice stating that you modified the file.)

             **Origin**
             - Clause 1 of the IJG License
             - Clause 2 of the zlib License

         3.  You must include the IJG README file, and you must not alter any of the
             copyright or license text in that file.

             **Origin**
             - Clause 1 of the IJG License

     2.  If you are distributing only libjpeg-turbo binaries without the source, or
         if you are distributing an application that statically links with
         libjpeg-turbo, then:

         1.  Your product documentation must include a message stating:

             This software is based in part on the work of the Independent JPEG
             Group.

             **Origin**
             - Clause 2 of the IJG license

         2.  If your binary distribution includes or uses the TurboJPEG API, then
             your product documentation must include the text of the Modified BSD
             License (see below.)

             **Origin**
             - Clause 2 of the Modified BSD License

     3.  You cannot use the name of the IJG or The libjpeg-turbo Project or the
         contributors thereof in advertising, publicity, etc.

         **Origin**
         - IJG License
         - Clause 3 of the Modified BSD License

     4.  The IJG and The libjpeg-turbo Project do not warrant libjpeg-turbo to be
         free of defects, nor do we accept any liability for undesirable
         consequences resulting from your use of the software.

         **Origin**
         - IJG License
         - Modified BSD License
         - zlib License

     The Modified (3-clause) BSD License
     ===================================

     Copyright (C)2009-2023 D. R. Commander.  All Rights Reserved.&lt;br&gt;
     Copyright (C)2015 Viktor Szathmáry.  All Rights Reserved.

     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions are met:

     - Redistributions of source code must retain the above copyright notice,
       this list of conditions and the following disclaimer.
     - Redistributions in binary form must reproduce the above copyright notice,
       this list of conditions and the following disclaimer in the documentation
       and/or other materials provided with the distribution.
     - Neither the name of the libjpeg-turbo Project nor the names of its
       contributors may be used to endorse or promote products derived from this
       software without specific prior written permission.

     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS &quot;AS IS&quot;,
     AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
     LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     POSSIBILITY OF SUCH DAMAGE.

     Why Three Licenses?
     ===================

     The zlib License could have been used instead of the Modified (3-clause) BSD
     License, and since the IJG License effectively subsumes the distribution
     conditions of the zlib License, this would have effectively placed
     libjpeg-turbo binary distributions under the IJG License.  However, the IJG
     License specifically refers to the Independent JPEG Group and does not extend
     attribution and endorsement protections to other entities.  Thus, it was
     desirable to choose a license that granted us the same protections for new code
     that were granted to the IJG for code derived from their software.