af618ffe09
- Rename jpeg_simple_lossless() to jpeg_enable_lossless() and modify the
function so that it stores the lossless parameters directly in the Ss
and Al fields of jpeg_compress_struct rather than using a scan script.
- Move the cjpeg -lossless switch into "Switches for advanced users".
- Document the libjpeg API and run-time features that are unavailable in
lossless mode, and ensure that all parameters, functions, and switches
related to unavailable features are ignored or generate errors in
lossless mode.
- Defer any action that depends on whether lossless mode is enabled
until jpeg_start_compress()/jpeg_start_decompress() is called.
- Document the purpose of the point transform value.
- "Codec" stands for coder/decoder, so it is a bit awkward to say
"lossless compression codec" and "lossless decompression codec".
Use "lossless compressor" and "lossless decompressor" instead.
- Restore backward API/ABI compatibility with libjpeg v6b:
* Move the new 'lossless' field from the exposed jpeg_compress_struct
and jpeg_decompress_struct structures into the opaque
jpeg_comp_master and jpeg_decomp_master structures, and allocate the
master structures in the body of jpeg_create_compress() and
jpeg_create_decompress().
* Remove the new 'process' field from jpeg_compress_struct and
jpeg_decompress_struct and replace it with the old
'progressive_mode' field and the new 'lossless' field.
* Remove the new 'data_unit' field from jpeg_compress_struct and
jpeg_decompress_struct and replace it with a locally-computed
data unit variable.
* Restore the names of macros and fields that refer to DCT blocks, and
document that they have a different meaning in lossless mode. (Most
of them aren't very meaningful in lossless mode anyhow.)
* Remove the new alloc_darray() method from jpeg_memory_mgr and
replace it with an internal macro that wraps the alloc_sarray()
method.
* Move the JDIFF* data types from jpeglib.h and jmorecfg.h into
jpegint.h.
* Remove the new 'codec' field from jpeg_compress_struct and
jpeg_decompress_struct and instead reuse the existing internal
coefficient control, forward/inverse DCT, and entropy
encoding/decoding structures for lossless compression/decompression.
* Repurpose existing error codes rather than introducing new ones.
(The new JERR_BAD_RESTART and JWRN_MUST_DOWNSCALE codes remain,
although JWRN_MUST_DOWNSCALE will probably be removed in
libjpeg-turbo, since we have a different way of handling multiple
data precisions.)
- Automatically enable lossless mode when a scan script with parameters
that are only valid for lossless mode is detected, and document the
use of scan scripts to generate lossless JPEG images.
- Move the sequential and shared Huffman routines back into jchuff.c and
jdhuff.c, and document that those routines are shared with jclhuff.c
and jdlhuff.c as well as with jcphuff.c and jdphuff.c.
- Move MAX_DIFF_BITS from jchuff.h into jclhuff.c, the only place where
it is used.
- Move the predictor and scaler code into jclossls.c and jdlossls.c.
- Streamline register usage in the [un]differencers (inspired by similar
optimizations in the color [de]converters.)
- Restructure the logic in a few places to reduce duplicated code.
- Ensure that all lossless-specific code is guarded by
C_LOSSLESS_SUPPORTED or D_LOSSLESS_SUPPORTED and that the library can
be built successfully if either or both of those macros is undefined.
- Remove all short forms of external names introduced by the lossless
JPEG patch. (These will not be needed by libjpeg-turbo, so there is
no use cleaning them up.)
- Various wordsmithing, formatting, and punctuation tweaks
- Eliminate various compiler warnings.
236 lines
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236 lines
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IJG JPEG LIBRARY: FILE LIST
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This file was part of the Independent JPEG Group's software:
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Copyright (C) 1994-1998, Thomas G. Lane.
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Lossless JPEG Modifications:
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Copyright (C) 1999, Ken Murchison.
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Copyright (C) 2022, D. R. Commander.
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For conditions of distribution and use, see the accompanying README file.
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Here is a road map to the files in the IJG JPEG distribution. The
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distribution includes the JPEG library proper, plus two application
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programs ("cjpeg" and "djpeg") which use the library to convert JPEG
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files to and from some other popular image formats. A third application
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"jpegtran" uses the library to do lossless conversion between different
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variants of JPEG. There are also two stand-alone applications,
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"rdjpgcom" and "wrjpgcom".
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THE JPEG LIBRARY
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================
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Include files:
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jpeglib.h JPEG library's exported data and function declarations.
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jconfig.h Configuration declarations. Note: this file is not present
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in the distribution; it is generated during installation.
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jmorecfg.h Additional configuration declarations; need not be changed
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for a standard installation.
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jerror.h Declares JPEG library's error and trace message codes.
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jinclude.h Central include file used by all IJG .c files to reference
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system include files.
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jpegint.h JPEG library's internal data structures.
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jlossls.h JPEG library's lossless codec data structures.
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jchuff.h Private declarations for Huffman encoder modules.
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jdhuff.h Private declarations for Huffman decoder modules.
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jdct.h Private declarations for forward & reverse DCT subsystems.
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jmemsys.h Private declarations for memory management subsystem.
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jversion.h Version information.
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Applications using the library should include jpeglib.h (which in turn
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includes jconfig.h and jmorecfg.h). Optionally, jerror.h may be included
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if the application needs to reference individual JPEG error codes. The
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other include files are intended for internal use and would not normally
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be included by an application program. (cjpeg/djpeg/etc do use jinclude.h,
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since its function is to improve portability of the whole IJG distribution.
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Most other applications will directly include the system include files they
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want, and hence won't need jinclude.h.)
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C source code files:
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These files contain most of the functions intended to be called directly by
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an application program:
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jcapimin.c Application program interface: core routines for compression.
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jcapistd.c Application program interface: standard compression.
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jdapimin.c Application program interface: core routines for decompression.
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jdapistd.c Application program interface: standard decompression.
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jcomapi.c Application program interface routines common to compression
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and decompression.
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jcparam.c Compression parameter setting helper routines.
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jctrans.c API and library routines for transcoding compression.
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jdtrans.c API and library routines for transcoding decompression.
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Compression side of the library:
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jcinit.c Initialization: determines which other modules to use.
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jcmaster.c Master control: setup and inter-pass sequencing logic.
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jcmainct.c Main buffer controller (preprocessor => JPEG compressor).
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jcprepct.c Preprocessor buffer controller.
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jccolor.c Color space conversion.
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jcsample.c Downsampling.
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jchuff.c Shared Huffman entropy encoding routines.
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jcmarker.c JPEG marker writing.
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jdatadst.c Data destination manager for stdio output.
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Lossy (DCT) codec:
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jccoefct.c Buffer controller for DCT coefficient buffer.
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jcdctmgr.c DCT manager (DCT implementation selection & control).
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jfdctint.c Forward DCT using slow-but-accurate integer method.
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jfdctfst.c Forward DCT using faster, less accurate integer method.
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jfdctflt.c Forward DCT using floating-point arithmetic.
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jchuff.c Huffman entropy coding for sequential JPEG.
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jcphuff.c Huffman entropy coding for progressive JPEG.
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Lossless (spatial) codec:
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jcdiffct.c Buffer controller for difference buffer.
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jclossls.c Prediction, sample differencing, and point transform
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jclhuff.c Huffman entropy encoding for lossless JPEG.
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Decompression side of the library:
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jdmaster.c Master control: determines which other modules to use.
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jdinput.c Input controller: controls input processing modules.
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jdmainct.c Main buffer controller (JPEG decompressor => postprocessor).
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jdpostct.c Postprocessor buffer controller.
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jdmarker.c JPEG marker reading.
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jdhuff.c Shared Huffman entropy decoding routines.
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jdsample.c Upsampling.
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jdcolor.c Color space conversion.
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jdmerge.c Merged upsampling/color conversion (faster, lower quality).
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jquant1.c One-pass color quantization using a fixed-spacing colormap.
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jquant2.c Two-pass color quantization using a custom-generated colormap.
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Also handles one-pass quantization to an externally given map.
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jdatasrc.c Data source manager for stdio input.
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Lossy (DCT) codec:
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jdcoefct.c Buffer controller for DCT coefficient buffer.
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jdhuff.c Huffman entropy decoding for sequential JPEG.
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jdphuff.c Huffman entropy decoding for progressive JPEG.
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jddctmgr.c IDCT manager (IDCT implementation selection & control).
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jidctint.c Inverse DCT using slow-but-accurate integer method.
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jidctfst.c Inverse DCT using faster, less accurate integer method.
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jidctflt.c Inverse DCT using floating-point arithmetic.
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jidctred.c Inverse DCTs with reduced-size outputs.
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Lossless (spatial) codec:
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jddiffct.c Buffer controller for difference buffer.
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jdlossls.c Prediction, sample undifferencing, point transform, and sample
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scaling
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jdlhuff.c Huffman entropy decoding for lossless JPEG.
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Support files for both compression and decompression:
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jerror.c Standard error handling routines (application replaceable).
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jmemmgr.c System-independent (more or less) memory management code.
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jutils.c Miscellaneous utility routines.
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jmemmgr.c relies on a system-dependent memory management module. The IJG
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distribution includes the following implementations of the system-dependent
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module:
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jmemnobs.c "No backing store": assumes adequate virtual memory exists.
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jmemansi.c Makes temporary files with ANSI-standard routine tmpfile().
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jmemname.c Makes temporary files with program-generated file names.
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jmemdos.c Custom implementation for MS-DOS (16-bit environment only):
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can use extended and expanded memory as well as temp files.
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jmemmac.c Custom implementation for Apple Macintosh.
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Exactly one of the system-dependent modules should be configured into an
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installed JPEG library (see install.doc for hints about which one to use).
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On unusual systems you may find it worthwhile to make a special
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system-dependent memory manager.
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Non-C source code files:
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jmemdosa.asm 80x86 assembly code support for jmemdos.c; used only in
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MS-DOS-specific configurations of the JPEG library.
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CJPEG/DJPEG/JPEGTRAN
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====================
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Include files:
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cdjpeg.h Declarations shared by cjpeg/djpeg/jpegtran modules.
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cderror.h Additional error and trace message codes for cjpeg et al.
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transupp.h Declarations for jpegtran support routines in transupp.c.
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C source code files:
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cjpeg.c Main program for cjpeg.
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djpeg.c Main program for djpeg.
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jpegtran.c Main program for jpegtran.
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cdjpeg.c Utility routines used by all three programs.
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rdcolmap.c Code to read a colormap file for djpeg's "-map" switch.
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rdswitch.c Code to process some of cjpeg's more complex switches.
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Also used by jpegtran.
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transupp.c Support code for jpegtran: lossless image manipulations.
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Image file reader modules for cjpeg:
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rdbmp.c BMP file input.
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rdgif.c GIF file input (now just a stub).
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rdppm.c PPM/PGM file input.
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rdrle.c Utah RLE file input.
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rdtarga.c Targa file input.
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Image file writer modules for djpeg:
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wrbmp.c BMP file output.
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wrgif.c GIF file output (a mere shadow of its former self).
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wrppm.c PPM/PGM file output.
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wrrle.c Utah RLE file output.
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wrtarga.c Targa file output.
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RDJPGCOM/WRJPGCOM
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=================
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C source code files:
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rdjpgcom.c Stand-alone rdjpgcom application.
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wrjpgcom.c Stand-alone wrjpgcom application.
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These programs do not depend on the IJG library. They do use
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jconfig.h and jinclude.h, only to improve portability.
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ADDITIONAL FILES
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================
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Documentation (see README for a guide to the documentation files):
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README Master documentation file.
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*.doc Other documentation files.
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*.1 Documentation in Unix man page format.
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change.log Version-to-version change highlights.
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example.c Sample code for calling JPEG library.
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Configuration/installation files and programs (see install.doc for more info):
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configure Unix shell script to perform automatic configuration.
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ltconfig Support scripts for configure (from GNU libtool).
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ltmain.sh
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config.guess
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config.sub
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install-sh Install shell script for those Unix systems lacking one.
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ckconfig.c Program to generate jconfig.h on non-Unix systems.
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jconfig.doc Template for making jconfig.h by hand.
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makefile.* Sample makefiles for particular systems.
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jconfig.* Sample jconfig.h for particular systems.
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ansi2knr.c De-ANSIfier for pre-ANSI C compilers (courtesy of
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L. Peter Deutsch and Aladdin Enterprises).
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Test files (see install.doc for test procedure):
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test*.* Source and comparison files for confidence test.
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These are binary image files, NOT text files.
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