jpeg(n) JPEG image manipulation jpeg(n) 







jpeg - JPEG querying and manipulation of meta data








package require Tcl 8.2


package require jpeg ?0.3.5?


::jpeg::isJPEG file


::jpeg::imageInfo file


::jpeg::dimensions file


::jpeg::getThumbnail file


::jpeg::getExif file ?section?


::jpeg::formatExif keys


::jpeg::exifKeys


::jpeg::removeExif file


::jpeg::stripJPEG file


::jpeg::getComments file


::jpeg::addComment file text...


::jpeg::removeComments file


::jpeg::replaceComment file text


::jpeg::debug file


::jpeg::markers channel












This package provides commands to query and modify JPEG images.
    JPEG stands for Joint Photography Experts Group and is a standard for
    the lossy compression of photographical images. It is specified at
    LINK_HERE.









  
::jpeg::isJPEG file

  
Returns a boolean value indicating if file is a JPEG image.

  
::jpeg::imageInfo file

  
Returns a dictionary with keys version, units,
      xdensity, ydensity, xthumb, and ythumb. The
      values are the associated properties of the JPEG image in file.
      Throws an error if file is not a JPEG image.

  
::jpeg::dimensions file

  
Returns the dimensions of the JPEG file as a list of the horizontal
      and vertical pixel count. Throws an error if file is not a JPEG
      image.

  
::jpeg::getThumbnail file

  
This procedure will return the binary thumbnail image data, if a JPEG
      thumbnail is included in file, and the empty string otherwise. Note
      that it is possible to include thumbnails in formats other than JPEG
      although that is not common. The command finds thumbnails that are encoded
      in either the JFXX or EXIF segments of the JPEG information. If both are
      present the EXIF thumbnail will take precedence. Throws an error if
      file is not a JPEG image.
    
    set fh [open thumbnail.jpg w+]
    fconfigure $fh -translation binary -encoding binary
    puts -nonewline $fh [::jpeg::getThumbnail photo.jpg]
    close $fh
    

  

  
::jpeg::getExif file ?section?

  
section must be one of main or thumbnail. The default
      is main. Returns a dictionary containing the EXIF information for
      the specified section. For example:
    

    
    set exif {
	Make     Canon
	Model    {Canon DIGITAL IXUS}
	DateTime {2001:06:09 15:17:32}
    }
    

    Throws an error if file is not a JPEG image.

  
::jpeg::formatExif keys

  
Takes a list of key-value pairs as returned by getExif and formats
      many of the values into a more human readable form. As few as one
      key-value may be passed in, the entire exif is not required.
    
    foreach {key val} [::jpeg::formatExif [::jpeg::getExif photo.jpg]] {
        puts "$key: $val"
    }
    

    

    
    array set exif [::jpeg::getExif photo.jpg]
    puts "max f-stop: [::jpeg::formatExif [list MaxAperture $exif(MaxAperture)]]
    

  

  
::jpeg::exifKeys

  
Returns a list of the EXIF keys which are currently understood. There may
      be keys present in getExif data that are not understood. Those keys
      will appear in a 4 digit hexadecimal format.

  
::jpeg::removeExif file

  
Removes the Exif data segment from the specified file and replaces it with
      a standard JFIF segment. Throws an error if file is not a JPEG
      image.

  
::jpeg::stripJPEG file

  
Removes all metadata from the JPEG file leaving only the image. This
      includes comments, EXIF segments, JFXX segments, and application specific
      segments. Throws an error if file is not a JPEG image.

  
::jpeg::getComments file

  
Returns a list containing all the JPEG comments found in the file.
      Throws an error if file is not a valid JPEG image.

  
::jpeg::addComment file text...

  
Adds one or more plain text comments to the JPEG image in
      file. Throws an error if file is not a valid JPEG
    image.

  
::jpeg::removeComments file

  
Removes all comments from the file specified. Throws an error if
      file is not a valid JPEG image.

  
::jpeg::replaceComment file text

  
Replaces the first comment in the file with the new text. This is
      merely a shortcut for ::jpeg::removeComments and
      ::jpeg::addComment Throws an error if file is not a valid
      JPEG image.

  
::jpeg::debug file

  
Prints everything we know about the given file in a nice format.

  
::jpeg::markers channel

  
This is an internal helper command, we document it for use by advanced
      users of the package. The argument channel is an open file handle
      positioned at the start of the first marker (usually 2 bytes). The command
      returns a list with one element for each JFIF marker found in the file.
      Each element consists of a list of the marker name, its offset in the
      file, and its length. The offset points to the beginning of the sections
      data, not the marker itself. The length is the length of the data from the
      offset listed to the start of the next marker.










can only work with files cant write exif data gps exif data not
    parsed makernote data not yet implemented








This document, and the package it describes, will undoubtedly
    contain bugs and other problems. Please report such in the category
    jpeg of the Tcllib SF Trackers
    [http://sourceforge.net/tracker/?group_id=12883]. Please also report any
    ideas for enhancements you may have for either package and/or
  documentation.








comment, exif, image, jfif, jpeg, thumbnail








File formats








Copyright (c) 2004-2005, Code: Aaron Faupell <afaupell@users.sourceforge.net>
Copyright (c) 2007, Code:  Andreas Kupries <andreas_kupries@users.sourceforge.net>
Copyright (c) 2004-2009, Doc:  Andreas Kupries <andreas_kupries@users.sourceforge.net>








  

    0.3.5
    jpeg