blob: 704d8b23c2ecf72f20b829f04baaf42ea78973dc [file] [log] [blame]
Thomas G. Lane36a4ccc1994-09-24 00:00:00 +00001CHANGE LOG for Independent JPEG Group's JPEG software
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Guido Vollbedinga4ecaac2010-05-16 00:00:00 +00004Version 8b 16-May-2010
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6
7Repair problem in new memory source manager with corrupt JPEG data.
8Thank to Ted Campbell and Samuel Chun for the report.
9
Guido Vollbedinga4ecaac2010-05-16 00:00:00 +000010
Guido Vollbedingf18f81b2010-02-28 00:00:00 +000011Version 8a 28-Feb-2010
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13
14Writing tables-only datastreams via jpeg_write_tables works again.
15
16Support 32-bit BMPs (RGB image with Alpha channel) for read in cjpeg.
17Thank to Brett Blackham for the suggestion.
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Guido Vollbedingf18f81b2010-02-28 00:00:00 +000019
Guido Vollbeding989630f2010-01-10 00:00:00 +000020Version 8 10-Jan-2010
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Guido Vollbeding989630f2010-01-10 00:00:00 +000023Add sanity check in BMP reader module to avoid cjpeg crash for empty input
24image (thank to Isaev Ildar of ISP RAS, Moscow, RU for reporting this error).
25
26Add data source and destination managers for read from and write to
27memory buffers. New API functions jpeg_mem_src and jpeg_mem_dest.
28Thank to Roberto Boni from Italy for the suggestion.
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Guido Vollbeding5996a252009-06-27 00:00:00 +000031Version 7 27-Jun-2009
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Guido Vollbeding5996a252009-06-27 00:00:00 +000034cjpeg -quality option has been extended for support of separate quality
35settings for luminance and chrominance (or in general, for every provided
36quantization table slot).
37New API function jpeg_default_qtables() and q_scale_factor array in library.
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Guido Vollbeding5996a252009-06-27 00:00:00 +000039Support arithmetic entropy encoding and decoding.
40Added files jaricom.c, jcarith.c, jdarith.c.
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Guido Vollbeding5996a252009-06-27 00:00:00 +000042jpegtran has a new "lossless" cropping feature.
43
44Implement -perfect option in jpegtran, new API function
45jtransform_perfect_transform() in transupp. (DP 204_perfect.dpatch)
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47Better error messages for jpegtran fopen failure.
48(DP 203_jpegtran_errmsg.dpatch)
49
50Fix byte order issue with 16bit PPM/PGM files in rdppm.c/wrppm.c:
51according to Netpbm, the de facto standard implementation of the PNM formats,
52the most significant byte is first. (DP 203_rdppm.dpatch)
53
54Add -raw option to rdjpgcom not to mangle the output.
55(DP 205_rdjpgcom_raw.dpatch)
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57Make rdjpgcom locale aware. (DP 201_rdjpgcom_locale.dpatch)
58
59Add extern "C" to jpeglib.h.
60This avoids the need to put extern "C" { ... } around #include "jpeglib.h"
61in your C++ application. Defining the symbol DONT_USE_EXTERN_C in the
62configuration prevents this. (DP 202_jpeglib.h_c++.dpatch)
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Thomas G. Lane5ead57a1998-03-27 00:00:00 +000065Version 6b 27-Mar-1998
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67
68jpegtran has new features for lossless image transformations (rotation
69and flipping) as well as "lossless" reduction to grayscale.
70
71jpegtran now copies comments by default; it has a -copy switch to enable
72copying all APPn blocks as well, or to suppress comments. (Formerly it
73always suppressed comments and APPn blocks.) jpegtran now also preserves
74JFIF version and resolution information.
75
76New decompressor library feature: COM and APPn markers found in the input
77file can be saved in memory for later use by the application. (Before,
78you had to code this up yourself with a custom marker processor.)
79
80There is an unused field "void * client_data" now in compress and decompress
81parameter structs; this may be useful in some applications.
82
83JFIF version number information is now saved by the decoder and accepted by
84the encoder. jpegtran uses this to copy the source file's version number,
85to ensure "jpegtran -copy all" won't create bogus files that contain JFXX
86extensions but claim to be version 1.01. Applications that generate their
87own JFXX extension markers also (finally) have a supported way to cause the
88encoder to emit JFIF version number 1.02.
89
90djpeg's trace mode reports JFIF 1.02 thumbnail images as such, rather
91than as unknown APP0 markers.
92
93In -verbose mode, djpeg and rdjpgcom will try to print the contents of
94APP12 markers as text. Some digital cameras store useful text information
95in APP12 markers.
96
97Handling of truncated data streams is more robust: blocks beyond the one in
98which the error occurs will be output as uniform gray, or left unchanged
99if decoding a progressive JPEG. The appearance no longer depends on the
100Huffman tables being used.
101
102Huffman tables are checked for validity much more carefully than before.
103
104To avoid the Unisys LZW patent, djpeg's GIF output capability has been
105changed to produce "uncompressed GIFs", and cjpeg's GIF input capability
106has been removed altogether. We're not happy about it either, but there
107seems to be no good alternative.
108
109The configure script now supports building libjpeg as a shared library
110on many flavors of Unix (all the ones that GNU libtool knows how to
111build shared libraries for). Use "./configure --enable-shared" to
112try this out.
113
114New jconfig file and makefiles for Microsoft Visual C++ and Developer Studio.
115Also, a jconfig file and a build script for Metrowerks CodeWarrior
116on Apple Macintosh. makefile.dj has been updated for DJGPP v2, and there
117are miscellaneous other minor improvements in the makefiles.
118
119jmemmac.c now knows how to create temporary files following Mac System 7
120conventions.
121
122djpeg's -map switch is now able to read raw-format PPM files reliably.
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124cjpeg -progressive -restart no longer generates any unnecessary DRI markers.
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126Multiple calls to jpeg_simple_progression for a single JPEG object
127no longer leak memory.
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129
Thomas G. Lane489583f1996-02-07 00:00:00 +0000130Version 6a 7-Feb-96
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132
133Library initialization sequence modified to detect version mismatches
134and struct field packing mismatches between library and calling application.
135This change requires applications to be recompiled, but does not require
136any application source code change.
137
138All routine declarations changed to the style "GLOBAL(type) name ...",
139that is, GLOBAL, LOCAL, METHODDEF, EXTERN are now macros taking the
140routine's return type as an argument. This makes it possible to add
141Microsoft-style linkage keywords to all the routines by changing just
142these macros. Note that any application code that was using these macros
143will have to be changed.
144
145DCT coefficient quantization tables are now stored in normal array order
146rather than zigzag order. Application code that calls jpeg_add_quant_table,
147or otherwise manipulates quantization tables directly, will need to be
148changed. If you need to make such code work with either older or newer
149versions of the library, a test like "#if JPEG_LIB_VERSION >= 61" is
150recommended.
151
152djpeg's trace capability now dumps DQT tables in natural order, not zigzag
153order. This allows the trace output to be made into a "-qtables" file
154more easily.
155
156New system-dependent memory manager module for use on Apple Macintosh.
157
158Fix bug in cjpeg's -smooth option: last one or two scanlines would be
159duplicates of the prior line unless the image height mod 16 was 1 or 2.
160
161Repair minor problems in VMS, BCC, MC6 makefiles.
162
163New configure script based on latest GNU Autoconf.
164
165Correct the list of include files needed by MetroWerks C for ccommand().
166
167Numerous small documentation updates.
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169
Thomas G. Lanebc79e061995-08-02 00:00:00 +0000170Version 6 2-Aug-95
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172
173Progressive JPEG support: library can read and write full progressive JPEG
174files. A "buffered image" mode supports incremental decoding for on-the-fly
175display of progressive images. Simply recompiling an existing IJG-v5-based
176decoder with v6 should allow it to read progressive files, though of course
177without any special progressive display.
178
179New "jpegtran" application performs lossless transcoding between different
180JPEG formats; primarily, it can be used to convert baseline to progressive
181JPEG and vice versa. In support of jpegtran, the library now allows lossless
182reading and writing of JPEG files as DCT coefficient arrays. This ability
183may be of use in other applications.
184
185Notes for programmers:
186* We changed jpeg_start_decompress() to be able to suspend; this makes all
187decoding modes available to suspending-input applications. However,
188existing applications that use suspending input will need to be changed
189to check the return value from jpeg_start_decompress(). You don't need to
190do anything if you don't use a suspending data source.
191* We changed the interface to the virtual array routines: access_virt_array
192routines now take a count of the number of rows to access this time. The
193last parameter to request_virt_array routines is now interpreted as the
194maximum number of rows that may be accessed at once, but not necessarily
195the height of every access.
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Thomas G. Lanea8b67c41995-03-15 00:00:00 +0000198Version 5b 15-Mar-95
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200
201Correct bugs with grayscale images having v_samp_factor > 1.
202
203jpeg_write_raw_data() now supports output suspension.
204
205Correct bugs in "configure" script for case of compiling in
206a directory other than the one containing the source files.
207
208Repair bug in jquant1.c: sometimes didn't use as many colors as it could.
209
210Borland C makefile and jconfig file work under either MS-DOS or OS/2.
211
212Miscellaneous improvements to documentation.
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Thomas G. Lane9ba2f5e1994-12-07 00:00:00 +0000215Version 5a 7-Dec-94
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217
218Changed color conversion roundoff behavior so that grayscale values are
219represented exactly. (This causes test image files to change.)
220
221Make ordered dither use 16x16 instead of 4x4 pattern for a small quality
222improvement.
223
224New configure script based on latest GNU Autoconf.
225Fix configure script to handle CFLAGS correctly.
226Rename *.auto files to *.cfg, so that configure script still works if
227file names have been truncated for DOS.
228
229Fix bug in rdbmp.c: didn't allow for extra data between header and image.
230
231Modify rdppm.c/wrppm.c to handle 2-byte raw PPM/PGM formats for 12-bit data.
232
233Fix several bugs in rdrle.c.
234
235NEED_SHORT_EXTERNAL_NAMES option was broken.
236
237Revise jerror.h/jerror.c for more flexibility in message table.
238
239Repair oversight in jmemname.c NO_MKTEMP case: file could be there
240but unreadable.
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Thomas G. Lane36a4ccc1994-09-24 00:00:00 +0000243Version 5 24-Sep-94
244--------------------
245
246Version 5 represents a nearly complete redesign and rewrite of the IJG
247software. Major user-visible changes include:
248 * Automatic configuration simplifies installation for most Unix systems.
249 * A range of speed vs. image quality tradeoffs are supported.
250 This includes resizing of an image during decompression: scaling down
251 by a factor of 1/2, 1/4, or 1/8 is handled very efficiently.
252 * New programs rdjpgcom and wrjpgcom allow insertion and extraction
253 of text comments in a JPEG file.
254
255The application programmer's interface to the library has changed completely.
256Notable improvements include:
257 * We have eliminated the use of callback routines for handling the
258 uncompressed image data. The application now sees the library as a
259 set of routines that it calls to read or write image data on a
260 scanline-by-scanline basis.
261 * The application image data is represented in a conventional interleaved-
262 pixel format, rather than as a separate array for each color channel.
263 This can save a copying step in many programs.
264 * The handling of compressed data has been cleaned up: the application can
265 supply routines to source or sink the compressed data. It is possible to
266 suspend processing on source/sink buffer overrun, although this is not
267 supported in all operating modes.
268 * All static state has been eliminated from the library, so that multiple
269 instances of compression or decompression can be active concurrently.
270 * JPEG abbreviated datastream formats are supported, ie, quantization and
271 Huffman tables can be stored separately from the image data.
272 * And not only that, but the documentation of the library has improved
273 considerably!
274
275
276The last widely used release before the version 5 rewrite was version 4A of
27718-Feb-93. Change logs before that point have been discarded, since they
278are not of much interest after the rewrite.