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e8b40f3c
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2022-11-01T21:45:39
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Vastly improve 12-bit JPEG integration
The Gordian knot that 7fec5074f962b20ed00b4f5da4533e1e8d4ed8ac attempted
to unravel was caused by the fact that there are several
data-precision-dependent (JSAMPLE-dependent) fields and methods in the
exposed libjpeg API structures, and if you change the exposed libjpeg
API structures, then you have to change the whole API. If you change
the whole API, then you have to provide a whole new library to support
the new API, and that makes it difficult to support multiple data
precisions in the same application. (It is not impossible, as example.c
demonstrated, but using data-precision-dependent libjpeg API structures
would have made the cjpeg, djpeg, and jpegtran source code hard to read,
so it made more sense to build, install, and package 12-bit-specific
versions of those applications.)
Unfortunately, the result of that initial integration effort was an
unreadable and unmaintainable mess, which is a problem for a library
that is an ISO/ITU-T reference implementation. Also, as I dug into the
problem of lossless JPEG support, I realized that 16-bit lossless JPEG
images are a thing, and supporting yet another version of the libjpeg
API just for those images is untenable.
In fact, however, the touch points for JSAMPLE in the exposed libjpeg
API structures are minimal:
- The colormap and sample_range_limit fields in jpeg_decompress_struct
- The alloc_sarray() and access_virt_sarray() methods in
jpeg_memory_mgr
- jpeg_write_scanlines() and jpeg_write_raw_data()
- jpeg_read_scanlines() and jpeg_read_raw_data()
- jpeg_skip_scanlines() and jpeg_crop_scanline()
(This is subtle, but both of those functions use JSAMPLE-dependent
opaque structures behind the scenes.)
It is much more readable and maintainable to provide 12-bit-specific
versions of those six top-level API functions and to document that the
aforementioned methods and fields must be type-cast when using 12-bit
samples. Since that eliminates the need to provide a 12-bit-specific
version of the exposed libjpeg API structures, we can:
- Compile only the precision-dependent libjpeg modules (the
coefficient buffer controllers, the colorspace converters, the
DCT/IDCT managers, the main buffer controllers, the preprocessing
and postprocessing controller, the downsampler and upsamplers, the
quantizers, the integer DCT methods, and the IDCT methods) for
multiple data precisions.
- Introduce 12-bit-specific methods into the various internal
structures defined in jpegint.h.
- Create precision-independent data type, macro, method, field, and
function names that are prefixed by an underscore, and use an
internal header to convert those into precision-dependent data
type, macro, method, field, and function names, based on the value
of BITS_IN_JSAMPLE, when compiling the precision-dependent libjpeg
modules.
- Expose precision-dependent jinit*() functions for each of the
precision-dependent libjpeg modules.
- Abstract the precision-dependent libjpeg modules by calling the
appropriate precision-dependent jinit*() function, based on the
value of cinfo->data_precision, from top-level libjpeg API
functions.
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7fec5074
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2022-03-08T12:34:11
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Support 8-bit & 12-bit JPEGs using the same build
Partially implements #199
This commit also implements a request from #178 (the ability to compile
the libjpeg example as a standalone program.)
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17297239
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2022-01-06T09:17:30
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Eliminate non-ANSI C compatibility macros
libjpeg-turbo has never supported non-ANSI C compilers. Per the spec,
ANSI C compilers must have locale.h, stddef.h, stdlib.h, memset(),
memcpy(), unsigned char, and unsigned short. They must also handle
undefined structures.
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4d9f256b
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2021-07-13T11:52:49
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jpegtran: Add option to copy only ICC markers
Closes #533
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cd342acf
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2020-10-27T16:42:14
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Merge branch 'master' into dev
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9ecb67c2
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2020-10-27T15:32:46
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transupp.c: Code formatting tweaks
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88ae6098
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2020-10-27T13:28:56
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Merge branch 'ijg' into dev
- Restore GIF read/compressed GIF write support from jpeg-6a and
jpeg-9d.
- Integrate jpegtran -wipe and -drop options from jpeg-9a and jpeg-9d.
- Integrate jpegtran -crop extension (for expanding the image size) from
jpeg-9a and jpeg-9d.
- Integrate other minor code tweaks from jpeg-9*
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9fc018fd
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2020-01-12T00:00:00
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The Independent JPEG Group's JPEG software v9d
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96e4e7eb
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2018-01-14T00:00:00
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The Independent JPEG Group's JPEG software v9c
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52fef349
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2019-12-10T19:10:55
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Eliminate internal use of GETJOCTET() macro
Because of 01e30323546d37792e4f682d78d58bb8b3e185ab (officially
eliminating support for compilers without unsigned char, since we never
effectively supported those compilers anyhow), GETJOCTET() is now a
no-op. Since that macro is in jmorecfg.h, it is part of the de facto
libjpeg API and must remain in the public headers. However, there is no
reason to continue using it internally, and eliminating its internal use
improves code readability.
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293263c3
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2018-03-17T15:14:35
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Format preprocessor macros more consistently
Within the libjpeg API code, it seems to be more the convention than not
to separate the macro name and value by two or more spaces, which
improves general readability. Making this consistent across all of
libjpeg-turbo is less about my individual preferences and more about
making it easy to automatically detect variations from our chosen
formatting convention. I intend to release the script I'm using to
validate this stuff, once it matures and stabilizes a bit.
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19c791cd
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2018-03-08T10:55:20
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Improve code formatting consistency
With rare exceptions ...
- Always separate line continuation characters by one space from
preceding code.
- Always use two-space indentation. Never use tabs.
- Always use K&R-style conditional blocks.
- Always surround operators with spaces, except in raw assembly code.
- Always put a space after, but not before, a comma.
- Never put a space between type casts and variables/function calls.
- Never put a space between the function name and the argument list in
function declarations and prototypes.
- Always surround braces ('{' and '}') with spaces.
- Always surround statements (if, for, else, catch, while, do, switch)
with spaces.
- Always attach pointer symbols ('*' and '**') to the variable or
function name.
- Always precede pointer symbols ('*' and '**') by a space in type
casts.
- Use the MIN() macro from jpegint.h within the libjpeg and TurboJPEG
API libraries (using min() from tjutil.h is still necessary for
TJBench.)
- Where it makes sense (particularly in the TurboJPEG code), put a blank
line after variable declaration blocks.
- Always separate statements in one-liners by two spaces.
The purpose of this was to ease maintenance on my part and also to make
it easier for contributors to figure out how to format patch
submissions. This was admittedly confusing (even to me sometimes) when
we had 3 or 4 different style conventions in the same source tree. The
new convention is more consistent with the formatting of other OSS code
bases.
This commit corrects deviations from the chosen formatting style in the
libjpeg API code and reformats the TurboJPEG API code such that it
conforms to the same standard.
NOTES:
- Although it is no longer necessary for the function name in function
declarations to begin in Column 1 (this was historically necessary
because of the ansi2knr utility, which allowed libjpeg to be built
with non-ANSI compilers), we retain that formatting for the libjpeg
code because it improves readability when using libjpeg's function
attribute macros (GLOBAL(), etc.)
- This reformatting project was accomplished with the help of AStyle and
Uncrustify, although neither was completely up to the task, and thus
a great deal of manual tweaking was required. Note to developers of
code formatting utilities: the libjpeg-turbo code base is an
excellent test bed, because AFAICT, it breaks every single one of the
utilities that are currently available.
- The legacy (MMX, SSE, 3DNow!) assembly code for i386 has been
formatted to match the SSE2 code (refer to
ff5685d5344273df321eb63a005eaae19d2496e3.) I hadn't intended to
bother with this, but the Loongson MMI implementation demonstrated
that there is still academic value to the MMX implementation, as an
algorithmic model for other 64-bit vector implementations. Thus, it
is desirable to improve its readability in the same manner as that of
the SSE2 implementation.
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44b2399a
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2017-01-19T15:18:57
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libjpeg API: Support reading/writing ICC profiles
This commit does the following:
-- Merges the two glueware functions (read_icc_profile() and
write_icc_profile()) from iccjpeg.c, which is contained in downstream
projects such as LCMS, Ghostscript, Mozilla, etc. These functions were
originally intended for inclusion in libjpeg, but Tom Lane left the IJG
before that could be accomplished. Since then, programs and libraries
that needed to embed/extract ICC profiles in JPEG files had to include
their own local copy of iccjpeg.c, which is suboptimal.
-- The new functions were prefixed with jpeg_ and split into separate
files for the compressor and decompressor, per the existing libjpeg
coding standards.
-- jpeg_write_icc_profile() was made slightly more fault-tolerant.
It will now trigger a libjpeg error if it is called before
jpeg_start_compress() or if it is passed NULL arguments.
-- jpeg_read_icc_profile() was made slightly more fault-tolerant.
It will now trigger a libjpeg error if it is called before
jpeg_read_header() or if it is passed NULL arguments. It will also
now trigger libjpeg warnings if the ICC profile data is corrupt.
-- The code comments have been wordsmithed.
-- Note that the one-line setup_read_icc_profile() function was not
included. Instead, libjpeg.txt now documents the need to call
jpeg_save_markers(cinfo, JPEG_APP0 + 2, 0xFFFF) prior to calling
jpeg_read_header(), if jpeg_read_icc_profile() is to be used.
-- Adds documentation for the new functions to libjpeg.txt.
-- Adds an -icc switch to cjpeg and jpegtran that allows those programs
to embed an ICC profile in the JPEG files they generate.
-- Adds an -icc switch to djpeg that allows that program to extract an
ICC profile from a JPEG file while decompressing.
-- Adds appropriate unit tests for all of the above.
-- Bumps the SO_AGE of the libjpeg API library to indicate the presence
of new API functions.
Note that the licensing information was obtained from:
https://github.com/mm2/Little-CMS/issues/37#issuecomment-66450180
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a0b7de9a
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2017-01-19T18:51:41
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Always tweak EXIF w/h tags w/ lossless transforms
... even if using libjpeg v6b emulation. Previously
adjust_exif_parameters() was only called with libjpeg v7/v8 emulation,
but due to a bug (which this commit also fixes), it only worked properly
with libjpeg v8 emulation.
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22527955
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2017-01-19T17:50:59
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Fix error w/ lossless crop & libjpeg v7 emulation
The JPEG_LIB_VERSION #ifdef in jtransform_adjust_parameters() was
incorrect, which caused a "Bogus virtual array access" error when
attempting to use the lossless crop feature.
Introduced in c04bd3cc97f44fd9030de1e141754c8775d4e5a5.
This also adds libjpeg v7 API/ABI emulation to the Travis CI tests.
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bd49803f
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2016-02-19T08:53:33
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Use consistent/modern code formatting for pointers
The convention used by libjpeg:
type * variable;
is not very common anymore, because it looks too much like
multiplication. Some (particularly C++ programmers) prefer to tuck the
pointer symbol against the type:
type* variable;
to emphasize that a pointer to a type is effectively a new type.
However, this can also be confusing, since defining multiple variables
on the same line would not work properly:
type* variable1, variable2; /* Only variable1 is actually a
pointer. */
This commit reformats the entirety of the libjpeg-turbo code base so
that it uses the same code formatting convention for pointers that the
TurboJPEG API code uses:
type *variable1, *variable2;
This seems to be the most common convention among C programmers, and
it is the convention used by other codec libraries, such as libpng and
libtiff.
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fc11193e
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2014-01-19T00:00:00
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The Independent JPEG Group's JPEG software v9a
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e7f88aec
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2013-01-13T00:00:00
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The Independent JPEG Group's JPEG software v9
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7e3acc0e
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2015-10-10T10:25:46
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Rename README, LICENSE, BUILDING text files
The IJG README file has been renamed to README.ijg, in order to avoid
confusion (many people were assuming that that was our project's README
file and weren't reading README-turbo.txt) and to lay the groundwork for
markdown versions of the libjpeg-turbo README and build instructions.
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5829cb23
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2012-01-15T00:00:00
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The Independent JPEG Group's JPEG software v8d
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989630f7
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2010-01-10T00:00:00
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The Independent JPEG Group's JPEG software v8
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5996a25e
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2009-06-27T00:00:00
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The Independent JPEG Group's JPEG software v7
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5ead57a3
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1998-03-27T00:00:00
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The Independent JPEG Group's JPEG software v6b
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5de454b2
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2014-05-18T19:04:03
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libjpeg-turbo has never supported non-ANSI compilers, so get rid of the crufty SIZEOF() macro. It was not being used consistently anyhow, so it would not have been possible to build prior releases of libjpeg-turbo using the broken compilers for which that macro was designed.
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1313 632fc199-4ca6-4c93-a231-07263d6284db
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5033f3e1
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2014-05-18T18:33:44
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Remove MS-DOS code and information, and adjust copyright headers to reflect the removal of features in r1307 and r1308. libjpeg-turbo has never supported MS-DOS, nor is it even possible for us to do so.
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1312 632fc199-4ca6-4c93-a231-07263d6284db
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b7753510
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2014-05-11T09:36:25
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Convert tabs to spaces in the libjpeg code and the SIMD code (TurboJPEG retains the use of tabs for historical reasons. They were annoying in the libjpeg code primarily because they were not consistently used and because they were used to format as well as indent the code. In the case of TurboJPEG, tabs are used just to indent the code, so even if the editor assumes a different tab width, the code will still be readable.)
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.3.x@1285 632fc199-4ca6-4c93-a231-07263d6284db
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e5eaf374
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2014-05-09T18:00:32
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Convert tabs to spaces in the libjpeg code and the SIMD code (TurboJPEG retains the use of tabs for historical reasons. They were annoying in the libjpeg code primarily because they were not consistently used and because they were used to format as well as indent the code. In the case of TurboJPEG, tabs are used just to indent the code, so even if the editor assumes a different tab width, the code will still be readable.)
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1278 632fc199-4ca6-4c93-a231-07263d6284db
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506a7421
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2014-03-21T09:29:28
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Fix compiler warning about unused function when building with the libjpeg v6b API/ABI
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.3.x@1189 632fc199-4ca6-4c93-a231-07263d6284db
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a6ef282a
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2013-09-28T03:23:49
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Some of the IJG headers say "Modified by", so clarify that our "Modifications" are not referring to these.
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.3.x@1053 632fc199-4ca6-4c93-a231-07263d6284db
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8cbf8939
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2013-01-01T10:44:00
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Port the width/height force feature from jpegtran v8d.
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@881 632fc199-4ca6-4c93-a231-07263d6284db
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cf763c0c
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2013-01-01T09:51:37
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Further changes to the copyright/attribution notices to make it clear that our modified files are not part of the IJG's software.
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.2.x@876 632fc199-4ca6-4c93-a231-07263d6284db
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a73e870a
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2012-12-31T02:52:30
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Change the copyright notices to make it clear that our modified files are not part of the IJG's software.
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.2.x@873 632fc199-4ca6-4c93-a231-07263d6284db
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ba5ea514
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2011-03-04T03:20:34
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Tile generation did not work with TJXFORM_HFLIP, because the underlying transform code was using an in-place algorithm, which modified the source coefficients after the first tile was generated. Thus, create a new option which allows TurboJPEG to turn off the in-place horizontal flip if there are multiple transforms being performed from the same set of coefficients.
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@495 632fc199-4ca6-4c93-a231-07263d6284db
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9a648cc9
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2010-10-10T02:48:21
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Fix transpose feature with jpeg v6b code base
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@244 632fc199-4ca6-4c93-a231-07263d6284db
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c04bd3cc
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2010-10-10T02:15:56
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Implement lossless crop feature from jpeg v7 and v8
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@243 632fc199-4ca6-4c93-a231-07263d6284db
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36a6eec9
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2010-10-08T08:05:44
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Added optional emulation of the jpeg-7 or jpeg-8b API/ABI's
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@236 632fc199-4ca6-4c93-a231-07263d6284db
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c8753072
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2006-05-25T05:01:55
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Migrating to new directory structure adopted from the RealVNC's source tree. More changes will follow.
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1 632fc199-4ca6-4c93-a231-07263d6284db
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