# exif(n) 1.1.2 exif "EXIF parsing"

## Name

exif - Tcl EXIF extracts and parses EXIF fields from digital images

## Table Of Contents

## Synopsis

- package require Tcl 8.2
- package require exif ?1.1.2?

- exif::analyze channel ?thumbnail?
- exif::analyzeFile filename ?thumbnail?
- exif::fieldnames

## Description

The EXIF package is a recoding of Chris Breeze's Perl package to do the same thing. This version accepts a channel as input and returns a serialized array with all the recognised fields parsed out.

There is also a function to obtain a list of all possible field names that might be present, which is useful in building GUIs that present such information.

## COMMANDS

exif::analyze channel ?thumbnail?

  channel should be an open file handle rewound to the start. It does not need to be seekable. channel will be set to binary mode and is left wherever it happens to stop being parsed, usually at the end of the file or the start of the image data. You must open and close the stream yourself. If no error is thrown, the return value is a serialized array with informative English text about what was found in the EXIF block. Failure during parsing or I/O throw errors.

  If thumbnail is present and not the empty string it will be interpreted as the name of a file, and the thumbnail image contained in the exif data will be written into it.

exif::analyzeFile filename ?thumbnail?

  This is a file-based wrapper around exif::analyze. Instead of taking a stream it takes a filename and analyzes the contents of the specified file.

exif::fieldnames

  This returns a list of all possible field names. That is, the array returned by exif::analyze will not contain keys that are not listed in the return from exif::fieldnames. Of course, if information is missing in the image file, exif::analyze may not return all the fields listed in the return from exif::fieldnames. This function is expected to be primarily useful for building GUIs to display results.

  N.B.: Read the implementation of exif::fieldnames before modifying the implementation of exif::analyze.

## COPYRIGHTS

(c) 2002 Darren New Hold harmless the author, and any lawful use is allowed.

## ACKNOWLEDGEMENTS

This code is a direct translation of version 1.3 of exif.pl by Chris Breeze. See the source for full headers, references, etc.

## BUGS, IDEAS, FEEDBACK

This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category exif of the Tcllib SF Trackers. Please also report any ideas for enhancements you may have for either package and/or documentation.

## Keywords

exif, jpeg, maker note, tiff

## Category

File formats