| Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 1 | CHANGE LOG for Independent JPEG Group's JPEG software |
| 2 | |
| 3 | |
| Thomas G. Lane | 9ba2f5e | 1994-12-07 00:00:00 +0000 | [diff] [blame^] | 4 | Version 5a 7-Dec-94 |
| 5 | -------------------- |
| 6 | |
| 7 | Changed color conversion roundoff behavior so that grayscale values are |
| 8 | represented exactly. (This causes test image files to change.) |
| 9 | |
| 10 | Make ordered dither use 16x16 instead of 4x4 pattern for a small quality |
| 11 | improvement. |
| 12 | |
| 13 | New configure script based on latest GNU Autoconf. |
| 14 | Fix configure script to handle CFLAGS correctly. |
| 15 | Rename *.auto files to *.cfg, so that configure script still works if |
| 16 | file names have been truncated for DOS. |
| 17 | |
| 18 | Fix bug in rdbmp.c: didn't allow for extra data between header and image. |
| 19 | |
| 20 | Modify rdppm.c/wrppm.c to handle 2-byte raw PPM/PGM formats for 12-bit data. |
| 21 | |
| 22 | Fix several bugs in rdrle.c. |
| 23 | |
| 24 | NEED_SHORT_EXTERNAL_NAMES option was broken. |
| 25 | |
| 26 | Revise jerror.h/jerror.c for more flexibility in message table. |
| 27 | |
| 28 | Repair oversight in jmemname.c NO_MKTEMP case: file could be there |
| 29 | but unreadable. |
| 30 | |
| 31 | |
| Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 32 | Version 5 24-Sep-94 |
| 33 | -------------------- |
| 34 | |
| 35 | Version 5 represents a nearly complete redesign and rewrite of the IJG |
| 36 | software. Major user-visible changes include: |
| 37 | * Automatic configuration simplifies installation for most Unix systems. |
| 38 | * A range of speed vs. image quality tradeoffs are supported. |
| 39 | This includes resizing of an image during decompression: scaling down |
| 40 | by a factor of 1/2, 1/4, or 1/8 is handled very efficiently. |
| 41 | * New programs rdjpgcom and wrjpgcom allow insertion and extraction |
| 42 | of text comments in a JPEG file. |
| 43 | |
| 44 | The application programmer's interface to the library has changed completely. |
| 45 | Notable improvements include: |
| 46 | * We have eliminated the use of callback routines for handling the |
| 47 | uncompressed image data. The application now sees the library as a |
| 48 | set of routines that it calls to read or write image data on a |
| 49 | scanline-by-scanline basis. |
| 50 | * The application image data is represented in a conventional interleaved- |
| 51 | pixel format, rather than as a separate array for each color channel. |
| 52 | This can save a copying step in many programs. |
| 53 | * The handling of compressed data has been cleaned up: the application can |
| 54 | supply routines to source or sink the compressed data. It is possible to |
| 55 | suspend processing on source/sink buffer overrun, although this is not |
| 56 | supported in all operating modes. |
| 57 | * All static state has been eliminated from the library, so that multiple |
| 58 | instances of compression or decompression can be active concurrently. |
| 59 | * JPEG abbreviated datastream formats are supported, ie, quantization and |
| 60 | Huffman tables can be stored separately from the image data. |
| 61 | * And not only that, but the documentation of the library has improved |
| 62 | considerably! |
| 63 | |
| 64 | |
| 65 | The last widely used release before the version 5 rewrite was version 4A of |
| 66 | 18-Feb-93. Change logs before that point have been discarded, since they |
| 67 | are not of much interest after the rewrite. |