kmx git

Commit	Date	Message
55bcad88	2024-06-24T22:16:07	Merge branch 'main' into dev
94c64ead	2024-06-17T20:27:57	Various doc tweaks - "bits per component" = "bits per sample" Describing the data precision of a JPEG image using "bits per component" is technically correct, but "bits per sample" is the terminology that the JPEG-1 spec uses. Also, "bits per component" is more commonly used to describe the precision of packed-pixel formats (as opposed to "bits per pixel") rather than planar formats, in which all components are grouped together. - Unmention legacy display technologies. Colormapped and monochrome displays aren't a thing anymore, and even when they were still a thing, it was possible to display full-color images to them. In 1991, when JPEG decompression time was measured in minutes per megapixel, it made sense to keep a decompressed copy of JPEG images on disk, in a format that could be displayed without further color conversion (since color conversion was slow and memory-intensive.) In 2024, JPEG decompression time is measured in milliseconds per megapixel, and color conversion is even faster. Thus, JPEG images can be decompressed, displayed, and color-converted (if necessary) "on the fly" at speeds too fast for human vision to perceive. (In fact, your TV performs much more complicated decompression algorithms at least 60 times per second.) - Document that color quantization (and associated features), GIF input/output, Targa input/output, and OS/2 BMP input/output are legacy features. Legacy status doesn't necessarily mean that the features are deprecated. Rather, it is meant to discourage users from using features that may be of little or no benefit on modern machines (such as low-quality modes that had significant performance advantages in the early 1990s but no longer do) and that are maintained on a break/fix basis only. - General wordsmithing, grammar/punctuation policing, and formatting tweaks - Clarify which data precisions each cjpeg input format and each djpeg output format supports. - cjpeg.1: Remove unnecessary and impolitic statement about the -targa switch. - Adjust or remove performance claims to reflect the fact that: * On modern machines, the djpeg "-fast" switch has a negligible effect on performance. * There is a measurable difference between the performance of Floyd- Steinberg dithering and no dithering, but it is not likely perceptible to most users. * There is a measurable difference between the performance of 1-pass and 2-pass color quantization, but it is not likely perceptible to most users. * There is a measurable difference between the performance of full-color and grayscale output when decompressing a full-color JPEG image, but it is not likely perceptible to most users. * IDCT scaling does not necessarily improve performance. (It generally does if the scaling factor is <= 1/2 and generally doesn't if the scaling factor is > 1/2, at least on my machine. The performance claim made in jpeg-6b was probably invalidated when we merged the additional scaling factors from jpeg-7.) - Clarify which djpeg switches/output formats cannot be used when decompressing lossless JPEG images. - Remove djpeg hints, since those involve quality vs. speed tradeoffs that are no longer relevant for modern machines. - Remove documentation regarding using color quantization with 16-bit data precision. (Color quantization requires lossy mode.) - Java: Fix typos in TJDecompressor.decompress12() and TJDecompressor.decompress16() documentation. - jpegtran.1: Fix truncated paragraph In a man page, a single quote at the start of a line is interpreted as a macro. Closes #775 - libjpeg.txt: * Mention J16SAMPLE data type (oversight.) * Remove statement about extending jdcolor.c. (libjpeg-turbo is not quite as DIY as libjpeg once was.) * Remove paragraph about tweaking the various typedefs in jmorecfg.h. It is no longer relevant for modern machines. * Remove caveat regarding systems with ints less than 16 bits wide. (ANSI/ISO C requires an int to be at least 16 bits wide, and libjpeg-turbo has never supported non-ANSI compilers.) - usage.txt: * Add copyright header. * Document cjpeg -icc, -memdst, -report, -strict, and -version switches. * Document djpeg -icc, -maxscans, -memsrc, -report, -skip, -crop, -strict, and -version switches. * Document jpegtran -icc, -maxscans, -report, -strict, and -version switches.
e69dd40c	2024-01-23T13:26:41	Reorganize source to make things easier to find - Move all libjpeg documentation, except for README.ijg, into the doc/ subdirectory. - Move the TurboJPEG C API documentation from doc/html/ into doc/turbojpeg/. - Move all C source code and headers into a src/ subdirectory. - Move turbojpeg-jni.c into the java/ subdirectory. Referring to #226, there is no ideal solution to this problem. A semantically ideal solution would have involved placing all source code, including the SIMD and Java source code, under src/ (or perhaps placing C library source code under lib/ and C test program source code under test/), all header files under include/, and all documentation under doc/. However: - To me it makes more sense to have separate top-level directories for each language, since the SIMD extensions and the Java API are technically optional features. src/ now contains only the code that is relevant to the core C API libraries and associated programs. - I didn't want to bury the java/ and simd/ directories or add a level of depth to them, since both directories already contain source code that is 3-4 levels deep. - I would prefer not to separate the header files from the C source code, because: 1. It would be disruptive. libjpeg and libjpeg-turbo have historically placed C source code and headers in the same directory, and people who are familiar with both projects (self included) are used to looking for the headers in the same directory as the C source code. 2. In terms of how the headers are used internally in libjpeg-turbo, the distinction between public and private headers is a bit fuzzy. - It didn't make sense to separate the test source code from the library source code, since there is not a clear distinction in some cases. (For instance, the IJG image I/O functions are used by cjpeg and djpeg as well as by the TurboJPEG API.) This solution is minimally disruptive, since it keeps all C source code and headers together and keeps java/ and simd/ as top-level directories. It is a bit awkward, because java/ and simd/ technically contain source code, even though they are not under src/. However, other solutions would have been more awkward for different reasons. Closes #226
97772cba	2022-11-14T15:36:25	Merge branch 'ijg.lossless' into dev Refer to #402
7fec5074	2022-03-08T12:34:11	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.)
88ae6098	2020-10-27T13:28:56	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*
26e3aedb	2020-10-22T23:04:24	README.ijg: Update URLs; remove Usenet info
84893085	2018-07-10T15:06:46	README.ijg: Clarification regarding JPEG 2000/XR The sentence: "Indeed, one of the original reasons for developing this free software was to help force convergence on common, interoperable format standards for JPEG files." might be seen to imply that JPEG 2000 and JPEG XR are not interoperable with themselves, although it is certainly the case that those formats are not interoperable with each other, nor with ITU T.81 \| ISO/IEC 10918. They are also certainly not as common as ITU T.81 \| ISO/IEC 10918, and (as an example) popular web browsers will not display JPEG 2000 files. The sentence in question was originally referring to proprietary, non-standard formats and was meant to provide historical context. libjpeg was originally released prior to the adoption of JFIF as an official standard, so it encouraged adoption of JFIF as a de facto standard by providing, under a business-friendly free software license, a library for reading and writing images in that format.
ed3c5273	2018-04-06T17:07:56	README.ijg: Wordsmith per ISO/ITU-T suggestions This commit merges the following paragraph from the latest libjpeg release: https://github.com/libjpeg-turbo/ijg/blob/jpeg-9c/README#L222-L229 which takes into account the fact that JFIF is now an official ISO/ITU-T standard. I also included the ISO/IEC document number for the JFIF spec (jpeg-9c included only the ITU-T rec number.) This commit also heavily wordsmiths the "FILE FORMAT WARS" section. In jpeg-7 and later, this section has become somewhat impolitic, referring to JPEG 2000 and JPEG XR as "faulty technologies" and "momentary mistakes." The original intent of this section, which was introduced in jpeg-5 and refined in jpeg-6 (https://github.com/libjpeg-turbo/ijg/blob/jpeg-5/README#L317-L338, https://github.com/libjpeg-turbo/ijg/blob/jpeg-6b/README#L335-L367) was to highlight the problem of JPEG file format divergence that existed in the 1990s prior to the adoption of JFIF as an official ISO/ITU-T standard. That problem is fortunately no longer a problem, thanks in part to the existence of libjpeg. I have attempted to preserve Tom's intent of using this section to describe which file formats the code is compatible with and why it isn't compatible with some file formats bearing the name "JPEG." Such modifications always put our project in a very awkward position, because we are not the IJG and do not claim to be, but it is still necessary for us to modify the IJG README file from time to time to eliminate obsolete information while attempting to remain as neutral as possible.
19c791cd	2018-03-08T10:55:20	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.
8c40ac8a	2017-11-16T18:46:01	Add TurboJPEG C example and clean up Java example Also rename example.c --> example.txt and add a disclaimer to that file so people will stop trying to compile it.
d9cb76f6	2017-01-16T15:55:02	Remove vestigial license text regarding autoconf
54e6b8e8	2016-02-18T15:16:17	Include some comments/doc tweaks from jpeg-9+
7e3acc0e	2015-10-10T10:25:46	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.

55bcad88

2024-06-24T22:16:07

Merge branch 'main' into dev

94c64ead

2024-06-17T20:27:57

Various doc tweaks - "bits per component" = "bits per sample" Describing the data precision of a JPEG image using "bits per component" is technically correct, but "bits per sample" is the terminology that the JPEG-1 spec uses. Also, "bits per component" is more commonly used to describe the precision of packed-pixel formats (as opposed to "bits per pixel") rather than planar formats, in which all components are grouped together. - Unmention legacy display technologies. Colormapped and monochrome displays aren't a thing anymore, and even when they were still a thing, it was possible to display full-color images to them. In 1991, when JPEG decompression time was measured in minutes per megapixel, it made sense to keep a decompressed copy of JPEG images on disk, in a format that could be displayed without further color conversion (since color conversion was slow and memory-intensive.) In 2024, JPEG decompression time is measured in milliseconds per megapixel, and color conversion is even faster. Thus, JPEG images can be decompressed, displayed, and color-converted (if necessary) "on the fly" at speeds too fast for human vision to perceive. (In fact, your TV performs much more complicated decompression algorithms at least 60 times per second.) - Document that color quantization (and associated features), GIF input/output, Targa input/output, and OS/2 BMP input/output are legacy features. Legacy status doesn't necessarily mean that the features are deprecated. Rather, it is meant to discourage users from using features that may be of little or no benefit on modern machines (such as low-quality modes that had significant performance advantages in the early 1990s but no longer do) and that are maintained on a break/fix basis only. - General wordsmithing, grammar/punctuation policing, and formatting tweaks - Clarify which data precisions each cjpeg input format and each djpeg output format supports. - cjpeg.1: Remove unnecessary and impolitic statement about the -targa switch. - Adjust or remove performance claims to reflect the fact that: * On modern machines, the djpeg "-fast" switch has a negligible effect on performance. * There is a measurable difference between the performance of Floyd- Steinberg dithering and no dithering, but it is not likely perceptible to most users. * There is a measurable difference between the performance of 1-pass and 2-pass color quantization, but it is not likely perceptible to most users. * There is a measurable difference between the performance of full-color and grayscale output when decompressing a full-color JPEG image, but it is not likely perceptible to most users. * IDCT scaling does not necessarily improve performance. (It generally does if the scaling factor is <= 1/2 and generally doesn't if the scaling factor is > 1/2, at least on my machine. The performance claim made in jpeg-6b was probably invalidated when we merged the additional scaling factors from jpeg-7.) - Clarify which djpeg switches/output formats cannot be used when decompressing lossless JPEG images. - Remove djpeg hints, since those involve quality vs. speed tradeoffs that are no longer relevant for modern machines. - Remove documentation regarding using color quantization with 16-bit data precision. (Color quantization requires lossy mode.) - Java: Fix typos in TJDecompressor.decompress12() and TJDecompressor.decompress16() documentation. - jpegtran.1: Fix truncated paragraph In a man page, a single quote at the start of a line is interpreted as a macro. Closes #775 - libjpeg.txt: * Mention J16SAMPLE data type (oversight.) * Remove statement about extending jdcolor.c. (libjpeg-turbo is not quite as DIY as libjpeg once was.) * Remove paragraph about tweaking the various typedefs in jmorecfg.h. It is no longer relevant for modern machines. * Remove caveat regarding systems with ints less than 16 bits wide. (ANSI/ISO C requires an int to be at least 16 bits wide, and libjpeg-turbo has never supported non-ANSI compilers.) - usage.txt: * Add copyright header. * Document cjpeg -icc, -memdst, -report, -strict, and -version switches. * Document djpeg -icc, -maxscans, -memsrc, -report, -skip, -crop, -strict, and -version switches. * Document jpegtran -icc, -maxscans, -report, -strict, and -version switches.

e69dd40c

2024-01-23T13:26:41

Reorganize source to make things easier to find - Move all libjpeg documentation, except for README.ijg, into the doc/ subdirectory. - Move the TurboJPEG C API documentation from doc/html/ into doc/turbojpeg/. - Move all C source code and headers into a src/ subdirectory. - Move turbojpeg-jni.c into the java/ subdirectory. Referring to #226, there is no ideal solution to this problem. A semantically ideal solution would have involved placing all source code, including the SIMD and Java source code, under src/ (or perhaps placing C library source code under lib/ and C test program source code under test/), all header files under include/, and all documentation under doc/. However: - To me it makes more sense to have separate top-level directories for each language, since the SIMD extensions and the Java API are technically optional features. src/ now contains only the code that is relevant to the core C API libraries and associated programs. - I didn't want to bury the java/ and simd/ directories or add a level of depth to them, since both directories already contain source code that is 3-4 levels deep. - I would prefer not to separate the header files from the C source code, because: 1. It would be disruptive. libjpeg and libjpeg-turbo have historically placed C source code and headers in the same directory, and people who are familiar with both projects (self included) are used to looking for the headers in the same directory as the C source code. 2. In terms of how the headers are used internally in libjpeg-turbo, the distinction between public and private headers is a bit fuzzy. - It didn't make sense to separate the test source code from the library source code, since there is not a clear distinction in some cases. (For instance, the IJG image I/O functions are used by cjpeg and djpeg as well as by the TurboJPEG API.) This solution is minimally disruptive, since it keeps all C source code and headers together and keeps java/ and simd/ as top-level directories. It is a bit awkward, because java/ and simd/ technically contain source code, even though they are not under src/. However, other solutions would have been more awkward for different reasons. Closes #226

97772cba

2022-11-14T15:36:25

Merge branch 'ijg.lossless' into dev Refer to #402

7fec5074

2022-03-08T12:34:11

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.)

88ae6098

2020-10-27T13:28:56

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*

26e3aedb

2020-10-22T23:04:24

README.ijg: Update URLs; remove Usenet info

84893085

2018-07-10T15:06:46

README.ijg: Clarification regarding JPEG 2000/XR The sentence: "Indeed, one of the original reasons for developing this free software was to help force convergence on common, interoperable format standards for JPEG files." might be seen to imply that JPEG 2000 and JPEG XR are not interoperable with themselves, although it is certainly the case that those formats are not interoperable with each other, nor with ITU T.81 | ISO/IEC 10918. They are also certainly not as common as ITU T.81 | ISO/IEC 10918, and (as an example) popular web browsers will not display JPEG 2000 files. The sentence in question was originally referring to proprietary, non-standard formats and was meant to provide historical context. libjpeg was originally released prior to the adoption of JFIF as an official standard, so it encouraged adoption of JFIF as a de facto standard by providing, under a business-friendly free software license, a library for reading and writing images in that format.

ed3c5273

2018-04-06T17:07:56

README.ijg: Wordsmith per ISO/ITU-T suggestions This commit merges the following paragraph from the latest libjpeg release: https://github.com/libjpeg-turbo/ijg/blob/jpeg-9c/README#L222-L229 which takes into account the fact that JFIF is now an official ISO/ITU-T standard. I also included the ISO/IEC document number for the JFIF spec (jpeg-9c included only the ITU-T rec number.) This commit also heavily wordsmiths the "FILE FORMAT WARS" section. In jpeg-7 and later, this section has become somewhat impolitic, referring to JPEG 2000 and JPEG XR as "faulty technologies" and "momentary mistakes." The original intent of this section, which was introduced in jpeg-5 and refined in jpeg-6 (https://github.com/libjpeg-turbo/ijg/blob/jpeg-5/README#L317-L338, https://github.com/libjpeg-turbo/ijg/blob/jpeg-6b/README#L335-L367) was to highlight the problem of JPEG file format divergence that existed in the 1990s prior to the adoption of JFIF as an official ISO/ITU-T standard. That problem is fortunately no longer a problem, thanks in part to the existence of libjpeg. I have attempted to preserve Tom's intent of using this section to describe which file formats the code is compatible with and why it isn't compatible with some file formats bearing the name "JPEG." Such modifications always put our project in a very awkward position, because we are not the IJG and do not claim to be, but it is still necessary for us to modify the IJG README file from time to time to eliminate obsolete information while attempting to remain as neutral as possible.

19c791cd

2018-03-08T10:55:20

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.

8c40ac8a

2017-11-16T18:46:01

Add TurboJPEG C example and clean up Java example Also rename example.c --> example.txt and add a disclaimer to that file so people will stop trying to compile it.

d9cb76f6

2017-01-16T15:55:02

Remove vestigial license text regarding autoconf

54e6b8e8

2016-02-18T15:16:17

Include some comments/doc tweaks from jpeg-9+

7e3acc0e

2015-10-10T10:25:46

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.

kc3-lang/libjpeg-turbo/README.ijg

README.ijg

Log