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diff --git a/libjpegtwrp/change.log b/libjpegtwrp/change.log new file mode 100644 index 000000000..74102c0db --- /dev/null +++ b/libjpegtwrp/change.log @@ -0,0 +1,217 @@ +CHANGE LOG for Independent JPEG Group's JPEG software + + +Version 6b 27-Mar-1998 +----------------------- + +jpegtran has new features for lossless image transformations (rotation +and flipping) as well as "lossless" reduction to grayscale. + +jpegtran now copies comments by default; it has a -copy switch to enable +copying all APPn blocks as well, or to suppress comments. (Formerly it +always suppressed comments and APPn blocks.) jpegtran now also preserves +JFIF version and resolution information. + +New decompressor library feature: COM and APPn markers found in the input +file can be saved in memory for later use by the application. (Before, +you had to code this up yourself with a custom marker processor.) + +There is an unused field "void * client_data" now in compress and decompress +parameter structs; this may be useful in some applications. + +JFIF version number information is now saved by the decoder and accepted by +the encoder. jpegtran uses this to copy the source file's version number, +to ensure "jpegtran -copy all" won't create bogus files that contain JFXX +extensions but claim to be version 1.01. Applications that generate their +own JFXX extension markers also (finally) have a supported way to cause the +encoder to emit JFIF version number 1.02. + +djpeg's trace mode reports JFIF 1.02 thumbnail images as such, rather +than as unknown APP0 markers. + +In -verbose mode, djpeg and rdjpgcom will try to print the contents of +APP12 markers as text. Some digital cameras store useful text information +in APP12 markers. + +Handling of truncated data streams is more robust: blocks beyond the one in +which the error occurs will be output as uniform gray, or left unchanged +if decoding a progressive JPEG. The appearance no longer depends on the +Huffman tables being used. + +Huffman tables are checked for validity much more carefully than before. + +To avoid the Unisys LZW patent, djpeg's GIF output capability has been +changed to produce "uncompressed GIFs", and cjpeg's GIF input capability +has been removed altogether. We're not happy about it either, but there +seems to be no good alternative. + +The configure script now supports building libjpeg as a shared library +on many flavors of Unix (all the ones that GNU libtool knows how to +build shared libraries for). Use "./configure --enable-shared" to +try this out. + +New jconfig file and makefiles for Microsoft Visual C++ and Developer Studio. +Also, a jconfig file and a build script for Metrowerks CodeWarrior +on Apple Macintosh. makefile.dj has been updated for DJGPP v2, and there +are miscellaneous other minor improvements in the makefiles. + +jmemmac.c now knows how to create temporary files following Mac System 7 +conventions. + +djpeg's -map switch is now able to read raw-format PPM files reliably. + +cjpeg -progressive -restart no longer generates any unnecessary DRI markers. + +Multiple calls to jpeg_simple_progression for a single JPEG object +no longer leak memory. + + +Version 6a 7-Feb-96 +-------------------- + +Library initialization sequence modified to detect version mismatches +and struct field packing mismatches between library and calling application. +This change requires applications to be recompiled, but does not require +any application source code change. + +All routine declarations changed to the style "GLOBAL(type) name ...", +that is, GLOBAL, LOCAL, METHODDEF, EXTERN are now macros taking the +routine's return type as an argument. This makes it possible to add +Microsoft-style linkage keywords to all the routines by changing just +these macros. Note that any application code that was using these macros +will have to be changed. + +DCT coefficient quantization tables are now stored in normal array order +rather than zigzag order. Application code that calls jpeg_add_quant_table, +or otherwise manipulates quantization tables directly, will need to be +changed. If you need to make such code work with either older or newer +versions of the library, a test like "#if JPEG_LIB_VERSION >= 61" is +recommended. + +djpeg's trace capability now dumps DQT tables in natural order, not zigzag +order. This allows the trace output to be made into a "-qtables" file +more easily. + +New system-dependent memory manager module for use on Apple Macintosh. + +Fix bug in cjpeg's -smooth option: last one or two scanlines would be +duplicates of the prior line unless the image height mod 16 was 1 or 2. + +Repair minor problems in VMS, BCC, MC6 makefiles. + +New configure script based on latest GNU Autoconf. + +Correct the list of include files needed by MetroWerks C for ccommand(). + +Numerous small documentation updates. + + +Version 6 2-Aug-95 +------------------- + +Progressive JPEG support: library can read and write full progressive JPEG +files. A "buffered image" mode supports incremental decoding for on-the-fly +display of progressive images. Simply recompiling an existing IJG-v5-based +decoder with v6 should allow it to read progressive files, though of course +without any special progressive display. + +New "jpegtran" application performs lossless transcoding between different +JPEG formats; primarily, it can be used to convert baseline to progressive +JPEG and vice versa. In support of jpegtran, the library now allows lossless +reading and writing of JPEG files as DCT coefficient arrays. This ability +may be of use in other applications. + +Notes for programmers: +* We changed jpeg_start_decompress() to be able to suspend; this makes all +decoding modes available to suspending-input applications. However, +existing applications that use suspending input will need to be changed +to check the return value from jpeg_start_decompress(). You don't need to +do anything if you don't use a suspending data source. +* We changed the interface to the virtual array routines: access_virt_array +routines now take a count of the number of rows to access this time. The +last parameter to request_virt_array routines is now interpreted as the +maximum number of rows that may be accessed at once, but not necessarily +the height of every access. + + +Version 5b 15-Mar-95 +--------------------- + +Correct bugs with grayscale images having v_samp_factor > 1. + +jpeg_write_raw_data() now supports output suspension. + +Correct bugs in "configure" script for case of compiling in +a directory other than the one containing the source files. + +Repair bug in jquant1.c: sometimes didn't use as many colors as it could. + +Borland C makefile and jconfig file work under either MS-DOS or OS/2. + +Miscellaneous improvements to documentation. + + +Version 5a 7-Dec-94 +-------------------- + +Changed color conversion roundoff behavior so that grayscale values are +represented exactly. (This causes test image files to change.) + +Make ordered dither use 16x16 instead of 4x4 pattern for a small quality +improvement. + +New configure script based on latest GNU Autoconf. +Fix configure script to handle CFLAGS correctly. +Rename *.auto files to *.cfg, so that configure script still works if +file names have been truncated for DOS. + +Fix bug in rdbmp.c: didn't allow for extra data between header and image. + +Modify rdppm.c/wrppm.c to handle 2-byte raw PPM/PGM formats for 12-bit data. + +Fix several bugs in rdrle.c. + +NEED_SHORT_EXTERNAL_NAMES option was broken. + +Revise jerror.h/jerror.c for more flexibility in message table. + +Repair oversight in jmemname.c NO_MKTEMP case: file could be there +but unreadable. + + +Version 5 24-Sep-94 +-------------------- + +Version 5 represents a nearly complete redesign and rewrite of the IJG +software. Major user-visible changes include: + * Automatic configuration simplifies installation for most Unix systems. + * A range of speed vs. image quality tradeoffs are supported. + This includes resizing of an image during decompression: scaling down + by a factor of 1/2, 1/4, or 1/8 is handled very efficiently. + * New programs rdjpgcom and wrjpgcom allow insertion and extraction + of text comments in a JPEG file. + +The application programmer's interface to the library has changed completely. +Notable improvements include: + * We have eliminated the use of callback routines for handling the + uncompressed image data. The application now sees the library as a + set of routines that it calls to read or write image data on a + scanline-by-scanline basis. + * The application image data is represented in a conventional interleaved- + pixel format, rather than as a separate array for each color channel. + This can save a copying step in many programs. + * The handling of compressed data has been cleaned up: the application can + supply routines to source or sink the compressed data. It is possible to + suspend processing on source/sink buffer overrun, although this is not + supported in all operating modes. + * All static state has been eliminated from the library, so that multiple + instances of compression or decompression can be active concurrently. + * JPEG abbreviated datastream formats are supported, ie, quantization and + Huffman tables can be stored separately from the image data. + * And not only that, but the documentation of the library has improved + considerably! + + +The last widely used release before the version 5 rewrite was version 4A of +18-Feb-93. Change logs before that point have been discarded, since they +are not of much interest after the rewrite. |