The Independent JPEG Group's JPEG software
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README for release 6b of 27-Mar-1998
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This distribution contains the sixth public 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.
Serious users of this software (particularly those incorporating it into
larger programs) should contact IJG at jpeg-info@uunet.uu.net to be added to
our electronic mailing list. Mailing list members are notified of updates
and have a chance to participate in technical discussions, etc.
This software is the work of Tom Lane, Philip Gladstone, Jim Boucher,
Lee Crocker, Julian Minguillon, Luis Ortiz, George Phillips, Davide Rossi,
Guido Vollbeding, Ge' Weijers, and other members of the Independent JPEG
Group.
IJG is not affiliated with the official ISO JPEG standards committee.
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.
RELATED SOFTWARE Other stuff you should get.
FILE FORMAT WARS Software *not* to get.
TO DO Plans for future IJG releases.
Other documentation files in the distribution are:
User documentation:
install.doc How to configure and install the IJG software.
usage.doc Usage instructions for cjpeg, djpeg, jpegtran,
rdjpgcom, and wrjpgcom.
*.1 Unix-style man pages for programs (same info as usage.doc).
wizard.doc Advanced usage instructions for JPEG wizards only.
change.log Version-to-version change highlights.
Programmer and internal documentation:
libjpeg.doc How to use the JPEG library in your own programs.
example.c Sample code for calling the JPEG library.
structure.doc Overview of the JPEG library's internal structure.
filelist.doc Road map of IJG files.
coderules.doc Coding style rules --- please read if you contribute code.
Please read at least the files install.doc and usage.doc. Useful 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 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. Hence you must not use JPEG if you
have to have identical output bits. However, on typical photographic images,
very good compression levels can be obtained with no visible change, and
remarkably high compression levels are possible if you can tolerate a
low-quality image. For more details, see the references, or just experiment
with various compression settings.
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.
For legal reasons, we are not distributing code for the arithmetic-coding
variants of JPEG; see LEGAL ISSUES. 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) 1991-1998, Thomas G. Lane.
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.
ansi2knr.c is included in this distribution by permission of
CxImage用法示例 （534个子文件） 
ANNOUNCE 1KB Image.aps 20KB pnggccrd.c 235KB pngvcrd.c 144KB pngrtran.c 143KB jbig.c 93KB pngrutil.c 92KB pngwutil.c 84KB tif_ojpeg.c 83KB fax3sm_winnt.c 79KB jpc_enc.c 72KB tif_getimage.c 64KB jpc_dec.c 62KB deflate.c 55KB jas_icc.c 50KB jquant2.c 49KB jpc_cs.c 48KB pngwrite.c 48KB pngread.c 47KB pngpread.c 46KB inflate.c 46KB trees.c 44KB tif_fax3.c 42KB jdmarker.c 42KB jmemmgr.c 41KB tif_jpeg.c 41KB jas_image.c 40KB pngset.c 39KB tif_luv.c 39KB tif_dirread.c 38KB jas_cm.c 37KB tif_dir.c 36KB tif_pixarlog.c 35KB jpc_qmfb.c 33KB jas_stream.c 32KB jquant1.c 31KB gzio.c 31KB tif_dirwrite.c 30KB jchuff.c 28KB jpc_t1enc.c 28KB jpc_t1dec.c 28KB jas_iccdata.c 28KB tif_lzw.c 27KB pngget.c 26KB jp2_cod.c 26KB tcd.c 26KB jbig_tab.c 25KB jcphuff.c 25KB jdcoefct.c 25KB png.c 24KB t1.c 24KB jdhuff.c 23KB infback.c 22KB j2k.c 22KB jpc_t2cod.c 22KB jcparam.c 21KB mif_cod.c 21KB jdphuff.c 21KB jdmainct.c 20KB jpc_t2enc.c 20KB jpc_tsfb.c 20KB pngtrans.c 20KB jcmaster.c 20KB jdmaster.c 20KB tif_write.c 20KB jp2_dec.c 19KB jcsample.c 19KB jpc_t2dec.c 19KB tif_read.c 18KB jcmarker.c 17KB pngwtran.c 17KB pngmem.c 17KB jdsample.c 16KB jccoefct.c 16KB tif_print.c 16KB pnm_dec.c 16KB pnm_enc.c 16KB jpc_bs.c 16KB tif_dirinfo.c 16KB bmp_dec.c 16KB jpg_enc.c 15KB tstcodec.c 15KB jccolor.c 15KB jidctint.c 15KB jpc_t1cod.c 15KB jp2_enc.c 14KB bmp_enc.c 14KB jas_seq.c 14KB jpc_mqenc.c 14KB jctrans.c 14KB jdmerge.c 14KB pi.c 14KB jidctred.c 14KB ras_dec.c 14KB jdinput.c 14KB inftrees.c 13KB jpg_dec.c 13KB jidctfst.c 13KB jdcolor.c 13KB tif_open.c 13KB共 534 条
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