NAME

tiff - TIFF reading, writing, and querying and manipulation of meta data

SYNOPSIS

package require Tcl 8.2

package require tiff ?0.2.1?

::tiff::isTIFF file

::tiff::byteOrder file

::tiff::numImages file

::tiff::dimensions file ?image?

::tiff::imageInfo file ?image?

::tiff::entries file ?image?

::tiff::getEntry file entry ?image?

::tiff::addEntry file entry ?image?

::tiff::deleteEntry file entry ?image?

::tiff::getImage file ?image?

::tiff::writeImage image file ?entry?

::tiff::nametotag names

::tiff::tagtoname tags

::tiff::debug file

DESCRIPTION

This package provides commands to query, modify, read, and write TIFF images. TIFF stands for Tagged Image File Format and is a standard for lossless storage of photographical images and associated metadata. It is specified at http://partners.adobe.com/public/developer/tiff/index.html.

Multiple images may be stored in a single TIFF file. The ?image? options to the functions in this package are for accessing images other than the first. Data in a TIFF image is stored as a series of tags having a numerical value, which are represented in either a 4 digit hexadecimal format or a string name. For a reference on defined tags and their meanings see http://www.awaresystems.be/imaging/tiff/tifftags.html

COMMANDS

::tiff::isTIFF file

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

::tiff::byteOrder file

Returns either big or little. Throws an error if file is not a TIFF image.

::tiff::numImages file

Returns the number of images in file. Throws an error if file is not a TIFF image.

::tiff::dimensions file ?image?

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

::tiff::imageInfo file ?image?

Returns a dictionary with keys ImageWidth, ImageLength, BitsPerSample, Compression, PhotometricInterpretation, ImageDescription, Orientation, XResolution, YResolution, ResolutionUnit, DateTime, Artist, and HostComputer. The values are the associated properties of the TIFF ?image? in file. Values may be empty if the associated tag is not present in the file.

    puts [::tiff::imageInfo photo.tif]
    ImageWidth 686 ImageLength 1024 BitsPerSample {8 8 8} Compression 1
    PhotometricInterpretation 2 ImageDescription {} Orientation 1
    XResolution 170.667 YResolution 170.667 ResolutionUnit 2 DateTime {2005:12:28 19:44:45}
    Artist {} HostComputer {}

There is nothing special about these tags, this is simply a convience procedure which calls getEntry with common entries. Throws an error if file is not a TIFF image.

::tiff::entries file ?image?

Returns a list of all entries in the given file and ?image? in hexadecimal format. Throws an error if file is not a TIFF image.

::tiff::getEntry file entry ?image?

Returns the value of entry from image ?image? in the TIFF file. entry may be a list of multiple entries. If an entry does not exist, an empty string is returned

    set data [::tiff::getEntry photo.tif {0131 0132}]
    puts "file was written at [lindex $data 0] with software [lindex $data 1]"

Throws an error if file is not a TIFF image.

::tiff::addEntry file entry ?image?

Adds the specified entries to the image named by ?image? (default 0), or optionally all. entry must be a list where each element is a list of tag, type, and value. If a tag already exists, it is overwritten.

    ::tiff::addEntry photo.tif {{010e 2 "an example photo"} {013b 2 "Aaron F"}}

The data types are defined as follows

1: BYTE (8 bit unsigned integer)
2: ASCII
3: SHORT (16 bit unsigned integer)
4: LONG (32 bit unsigned integer)
5: RATIONAL
6: SBYTE (8 bit signed byte)
7: UNDEFINED (uninterpreted binary data)
8: SSHORT (signed 16 bit integer)
9: SLONG (signed 32 bit integer)
10: SRATIONAL
11: FLOAT (32 bit floating point number)
12: DOUBLE (64 bit floating point number)

Throws an error if file is not a TIFF image.

::tiff::deleteEntry file entry ?image?: Deletes the specified entries from the image named by ?image? (default 0), or optionally all. Throws an error if file is not a TIFF image.
::tiff::getImage file ?image?: Returns the name of a Tk image containing the image at index ?image? from file Throws an error if file is not a TIFF image, or if image is an unsupported format. Supported formats are uncompressed 24 bit RGB and uncompressed 8 bit palette.
::tiff::writeImage image file ?entry?: Writes the contents of the Tk image image to a tiff file file. Files are written in the 24 bit uncompressed format, with big endian byte order. Additional entries to be added to the image may be specified, in the same format as tiff::addEntry
::tiff::nametotag names: Returns a list with names translated from string to 4 digit format. 4 digit names in the input are passed through unchanged. Strings without a defined tag name will throw an error.
::tiff::tagtoname tags: Returns a list with tags translated from 4 digit to string format. If a tag does not have a defined name it is passed through unchanged.
::tiff::debug file: Prints everything we know about the given file in a nice format.

VARIABLES

The mapping of 4 digit tag names to string names uses the array ::tiff::tiff_tags. The reverse mapping uses the array ::tiff::tiff_sgat.

LIMITATIONS

[1]: Cannot write exif ifd
[2]: Reading limited to uncompressed 8 bit rgb and 8 bit palletized images
[3]: Writing limited to uncompressed 8 bit rgb

BUGS, IDEAS, FEEDBACK

This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category tiff 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.

KEYWORDS

image, tif, tiff

COPYRIGHT

Copyright (c) 2005-2006, Aaron Faupell <afaupell@users.sourceforge.net>