Update to libjpeg_turbo 1.4.90

README

-libjpeg-turbo note:  This file has been modified by The libjpeg-turbo Project
-to include only information relevant to libjpeg-turbo, to wordsmith certain
-sections, and to remove impolitic language that existed in the libjpeg v8
-README.  It is included only for reference.  Please see README-turbo.txt for
-information specific to libjpeg-turbo.
-
-
-The Independent JPEG Group's JPEG software
-==========================================
-
-This distribution contains a release of the Independent JPEG Group's free JPEG
-software.  You are welcome to redistribute this software and to use it for any
-purpose, subject to the conditions under LEGAL ISSUES, below.
-
-This software is the work of Tom Lane, Guido Vollbeding, Philip Gladstone,
-Bill Allombert, Jim Boucher, Lee Crocker, Bob Friesenhahn, Ben Jackson,
-Julian Minguillon, Luis Ortiz, George Phillips, Davide Rossi, Ge' Weijers,
-and other members of the Independent JPEG Group.
-
-IJG is not affiliated with the ISO/IEC JTC1/SC29/WG1 standards committee
-(also known as JPEG, together with ITU-T SG16).
-
-
-DOCUMENTATION ROADMAP
-=====================
-
-This file contains the following sections:
-
-OVERVIEW            General description of JPEG and the IJG software.
-LEGAL ISSUES        Copyright, lack of warranty, terms of distribution.
-REFERENCES          Where to learn more about JPEG.
-ARCHIVE LOCATIONS   Where to find newer versions of this software.
-FILE FORMAT WARS    Software *not* to get.
-TO DO               Plans for future IJG releases.
-
-Other documentation files in the distribution are:
-
-User documentation:
-  install.txt       How to configure and install the IJG software.
-  usage.txt         Usage instructions for cjpeg, djpeg, jpegtran,
-                    rdjpgcom, and wrjpgcom.
-  *.1               Unix-style man pages for programs (same info as usage.txt).
-  wizard.txt        Advanced usage instructions for JPEG wizards only.
-  change.log        Version-to-version change highlights.
-Programmer and internal documentation:
-  libjpeg.txt       How to use the JPEG library in your own programs.
-  example.c         Sample code for calling the JPEG library.
-  structure.txt     Overview of the JPEG library's internal structure.
-  coderules.txt     Coding style rules --- please read if you contribute code.
-
-Please read at least the files install.txt and usage.txt.  Some information
-can also be found in the JPEG FAQ (Frequently Asked Questions) article.  See
-ARCHIVE LOCATIONS below to find out where to obtain the FAQ article.
-
-If you want to understand how the JPEG code works, we suggest reading one or
-more of the REFERENCES, then looking at the documentation files (in roughly
-the order listed) before diving into the code.
-
-
-OVERVIEW
-========
-
-This package contains C software to implement JPEG image encoding, decoding,
-and transcoding.  JPEG (pronounced "jay-peg") is a standardized compression
-method for full-color and gray-scale images.  JPEG's strong suit is compressing
-photographic images or other types of images that have smooth color and
-brightness transitions between neighboring pixels.  Images with sharp lines or
-other abrupt features may not compress well with JPEG, and a higher JPEG
-quality may have to be used to avoid visible compression artifacts with such
-images.
-
-JPEG is lossy, meaning that the output pixels are not necessarily identical to
-the input pixels.  However, on photographic content and other "smooth" images,
-very good compression ratios can be obtained with no visible compression
-artifacts, and extremely high compression ratios are possible if you are
-willing to sacrifice image quality (by reducing the "quality" setting in the
-compressor.)
-
-This software implements JPEG baseline, extended-sequential, and progressive
-compression processes.  Provision is made for supporting all variants of these
-processes, although some uncommon parameter settings aren't implemented yet.
-We have made no provision for supporting the hierarchical or lossless
-processes defined in the standard.
-
-We provide a set of library routines for reading and writing JPEG image files,
-plus two sample applications "cjpeg" and "djpeg", which use the library to
-perform conversion between JPEG and some other popular image file formats.
-The library is intended to be reused in other applications.
-
-In order to support file conversion and viewing software, we have included
-considerable functionality beyond the bare JPEG coding/decoding capability;
-for example, the color quantization modules are not strictly part of JPEG
-decoding, but they are essential for output to colormapped file formats or
-colormapped displays.  These extra functions can be compiled out of the
-library if not required for a particular application.
-
-We have also included "jpegtran", a utility for lossless transcoding between
-different JPEG processes, and "rdjpgcom" and "wrjpgcom", two simple
-applications for inserting and extracting textual comments in JFIF files.
-
-The emphasis in designing this software has been on achieving portability and
-flexibility, while also making it fast enough to be useful.  In particular,
-the software is not intended to be read as a tutorial on JPEG.  (See the
-REFERENCES section for introductory material.)  Rather, it is intended to
-be reliable, portable, industrial-strength code.  We do not claim to have
-achieved that goal in every aspect of the software, but we strive for it.
-
-We welcome the use of this software as a component of commercial products.
-No royalty is required, but we do ask for an acknowledgement in product
-documentation, as described under LEGAL ISSUES.
-
-
-LEGAL ISSUES
-============
-
-In plain English:
-
-1. We don't promise that this software works.  (But if you find any bugs,
-   please let us know!)
-2. You can use this software for whatever you want.  You don't have to pay us.
-3. You may not pretend that you wrote this software.  If you use it in a
-   program, you must acknowledge somewhere in your documentation that
-   you've used the IJG code.
-
-In legalese:
-
-The authors make NO WARRANTY or representation, either express or implied,
-with respect to this software, its quality, accuracy, merchantability, or
-fitness for a particular purpose.  This software is provided "AS IS", and you,
-its user, assume the entire risk as to its quality and accuracy.
-
-This software is copyright (C) 1991-2012, Thomas G. Lane, Guido Vollbeding.
-All Rights Reserved except as specified below.
-
-Permission is hereby granted to use, copy, modify, and distribute this
-software (or portions thereof) for any purpose, without fee, subject to these
-conditions:
-(1) If any part of the source code for this software is distributed, then this
-README file must be included, with this copyright and no-warranty notice
-unaltered; and any additions, deletions, or changes to the original files
-must be clearly indicated in accompanying documentation.
-(2) If only executable code is distributed, then the accompanying
-documentation must state that "this software is based in part on the work of
-the Independent JPEG Group".
-(3) Permission for use of this software is granted only if the user accepts
-full responsibility for any undesirable consequences; the authors accept
-NO LIABILITY for damages of any kind.
-
-These conditions apply to any software derived from or based on the IJG code,
-not just to the unmodified library.  If you use our work, you ought to
-acknowledge us.
-
-Permission is NOT granted for the use of any IJG author's name or company name
-in advertising or publicity relating to this software or products derived from
-it.  This software may be referred to only as "the Independent JPEG Group's
-software".
-
-We specifically permit and encourage the use of this software as the basis of
-commercial products, provided that all warranty or liability claims are
-assumed by the product vendor.
-
-
-The Unix configuration script "configure" was produced with GNU Autoconf.
-It is copyright by the Free Software Foundation but is freely distributable.
-The same holds for its supporting scripts (config.guess, config.sub,
-ltmain.sh).  Another support script, install-sh, is copyright by X Consortium
-but is also freely distributable.
-
-The IJG distribution formerly included code to read and write GIF files.
-To avoid entanglement with the Unisys LZW patent, GIF reading support has
-been removed altogether, and the GIF writer has been simplified to produce
-"uncompressed GIFs".  This technique does not use the LZW algorithm; the
-resulting GIF files are larger than usual, but are readable by all standard
-GIF decoders.
-
-We are required to state that
-    "The Graphics Interchange Format(c) is the Copyright property of
-    CompuServe Incorporated.  GIF(sm) is a Service Mark property of
-    CompuServe Incorporated."
-
-
-REFERENCES
-==========
-
-We recommend reading one or more of these references before trying to
-understand the innards of the JPEG software.
-
-The best short technical introduction to the JPEG compression algorithm is
-        Wallace, Gregory K.  "The JPEG Still Picture Compression Standard",
-        Communications of the ACM, April 1991 (vol. 34 no. 4), pp. 30-44.
-(Adjacent articles in that issue discuss MPEG motion picture compression,
-applications of JPEG, and related topics.)  If you don't have the CACM issue
-handy, a PostScript file containing a revised version of Wallace's article is
-available at http://www.ijg.org/files/wallace.ps.gz.  The file (actually
-a preprint for an article that appeared in IEEE Trans. Consumer Electronics)
-omits the sample images that appeared in CACM, but it includes corrections
-and some added material.  Note: the Wallace article is copyright ACM and IEEE,
-and it may not be used for commercial purposes.
-
-A somewhat less technical, more leisurely introduction to JPEG can be found in
-"The Data Compression Book" by Mark Nelson and Jean-loup Gailly, published by
-M&T Books (New York), 2nd ed. 1996, ISBN 1-55851-434-1.  This book provides
-good explanations and example C code for a multitude of compression methods
-including JPEG.  It is an excellent source if you are comfortable reading C
-code but don't know much about data compression in general.  The book's JPEG
-sample code is far from industrial-strength, but when you are ready to look
-at a full implementation, you've got one here...
-
-The best currently available description of JPEG is the textbook "JPEG Still
-Image Data Compression Standard" by William B. Pennebaker and Joan L.
-Mitchell, published by Van Nostrand Reinhold, 1993, ISBN 0-442-01272-1.
-Price US$59.95, 638 pp.  The book includes the complete text of the ISO JPEG
-standards (DIS 10918-1 and draft DIS 10918-2).
-
-The original JPEG standard is divided into two parts, Part 1 being the actual
-specification, while Part 2 covers compliance testing methods.  Part 1 is
-titled "Digital Compression and Coding of Continuous-tone Still Images,
-Part 1: Requirements and guidelines" and has document numbers ISO/IEC IS
-10918-1, ITU-T T.81.  Part 2 is titled "Digital Compression and Coding of
-Continuous-tone Still Images, Part 2: Compliance testing" and has document
-numbers ISO/IEC IS 10918-2, ITU-T T.83.
-
-The JPEG standard does not specify all details of an interchangeable file
-format.  For the omitted details we follow the "JFIF" conventions, revision
-1.02.  JFIF 1.02 has been adopted as an Ecma International Technical Report
-and thus received a formal publication status.  It is available as a free
-download in PDF format from
-http://www.ecma-international.org/publications/techreports/E-TR-098.htm.
-A PostScript version of the JFIF document is available at
-http://www.ijg.org/files/jfif.ps.gz.  There is also a plain text version at
-http://www.ijg.org/files/jfif.txt.gz, but it is missing the figures.
-
-The TIFF 6.0 file format specification can be obtained by FTP from
-ftp://ftp.sgi.com/graphics/tiff/TIFF6.ps.gz.  The JPEG incorporation scheme
-found in the TIFF 6.0 spec of 3-June-92 has a number of serious problems.
-IJG does not recommend use of the TIFF 6.0 design (TIFF Compression tag 6).
-Instead, we recommend the JPEG design proposed by TIFF Technical Note #2
-(Compression tag 7).  Copies of this Note can be obtained from
-http://www.ijg.org/files/.  It is expected that the next revision
-of the TIFF spec will replace the 6.0 JPEG design with the Note's design.
-Although IJG's own code does not support TIFF/JPEG, the free libtiff library
-uses our library to implement TIFF/JPEG per the Note.
-
-
-ARCHIVE LOCATIONS
-=================
-
-The "official" archive site for this software is www.ijg.org.
-The most recent released version can always be found there in
-directory "files".  This particular version will be archived as
-http://www.ijg.org/files/jpegsrc.v8d.tar.gz, and in Windows-compatible
-"zip" archive format as http://www.ijg.org/files/jpegsr8d.zip.
-
-The JPEG FAQ (Frequently Asked Questions) article is a source of some
-general information about JPEG.
-It is available on the World Wide Web at http://www.faqs.org/faqs/jpeg-faq/
-and other news.answers archive sites, including the official news.answers
-archive at rtfm.mit.edu: ftp://rtfm.mit.edu/pub/usenet/news.answers/jpeg-faq/.
-If you don't have Web or FTP access, send e-mail to mail-server@rtfm.mit.edu
-with body
-        send usenet/news.answers/jpeg-faq/part1
-        send usenet/news.answers/jpeg-faq/part2
-
-
-FILE FORMAT WARS
-================
-
-The ISO/IEC JTC1/SC29/WG1 standards committee (also known as JPEG, together
-with ITU-T SG16) currently promotes different formats containing the name
-"JPEG" which are incompatible with original DCT-based JPEG.  IJG therefore does
-not support these formats (see REFERENCES).  Indeed, one of the original
-reasons for developing this free software was to help force convergence on
-common, interoperable format standards for JPEG files.
-Don't use an incompatible file format!
-(In any case, our decoder will remain capable of reading existing JPEG
-image files indefinitely.)
-
-
-TO DO
-=====
-
-Please send bug reports, offers of help, etc. to jpeg-info@jpegclub.org.