kc3-lang/libjpeg-turbo/doc/wrjpgcom.1

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• Hash : e69dd40c
  Author :
  Date : 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
  

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• doc/wrjpgcom.1

• .TH WRJPGCOM 1 "15 June 1995"
  .SH NAME
  wrjpgcom \- insert text comments into a JPEG file
  .SH SYNOPSIS
  .B wrjpgcom
  [
  .B \-replace
  ]
  [
  .BI \-comment " text"
  ]
  [
  .BI \-cfile " name"
  ]
  [
  .I filename
  ]
  .LP
  .SH DESCRIPTION
  .LP
  .B wrjpgcom
  reads the named JPEG/JFIF file, or the standard input if no file is named,
  and generates a new JPEG/JFIF file on standard output.  A comment block is
  added to the file.
  .PP
  The JPEG standard allows "comment" (COM) blocks to occur within a JPEG file.
  Although the standard doesn't actually define what COM blocks are for, they
  are widely used to hold user-supplied text strings.  This lets you add
  annotations, titles, index terms, etc to your JPEG files, and later retrieve
  them as text.  COM blocks do not interfere with the image stored in the JPEG
  file.  The maximum size of a COM block is 64K, but you can have as many of
  them as you like in one JPEG file.
  .PP
  .B wrjpgcom
  adds a COM block, containing text you provide, to a JPEG file.
  Ordinarily, the COM block is added after any existing COM blocks; but you
  can delete the old COM blocks if you wish.
  .SH OPTIONS
  Switch names may be abbreviated, and are not case sensitive.
  .TP
  .B \-replace
  Delete any existing COM blocks from the file.
  .TP
  .BI \-comment " text"
  Supply text for new COM block on command line.
  .TP
  .BI \-cfile " name"
  Read text for new COM block from named file.
  .PP
  If you have only one line of comment text to add, you can provide it on the
  command line with
  .BR \-comment .
  The comment text must be surrounded with quotes so that it is treated as a
  single argument.  Longer comments can be read from a text file.
  .PP
  If you give neither
  .B \-comment
  nor
  .BR \-cfile,
  then
  .B wrjpgcom
  will read the comment text from standard input.  (In this case an input image
  file name MUST be supplied, so that the source JPEG file comes from somewhere
  else.)  You can enter multiple lines, up to 64KB worth.  Type an end-of-file
  indicator (usually control-D) to terminate the comment text entry.
  .PP
  .B wrjpgcom
  will not add a COM block if the provided comment string is empty.  Therefore
  \fB\-replace \-comment ""\fR can be used to delete all COM blocks from a file.
  .SH EXAMPLES
  .LP
  Add a short comment to in.jpg, producing out.jpg:
  .IP
  .B wrjpgcom \-c
  \fI"View of my back yard" in.jpg
  .B >
  .I out.jpg
  .PP
  Attach a long comment previously stored in comment.txt:
  .IP
  .B wrjpgcom
  .I in.jpg
  .B <
  .I comment.txt
  .B >
  .I out.jpg
  .PP
  or equivalently
  .IP
  .B wrjpgcom
  .B -cfile
  .I comment.txt
  .B <
  .I in.jpg
  .B >
  .I out.jpg
  .SH SEE ALSO
  .BR cjpeg (1),
  .BR djpeg (1),
  .BR jpegtran (1),
  .BR rdjpgcom (1)
  .SH AUTHOR
  Independent JPEG Group
  

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