Provided by: libgraphics-tiff-perl_19-1build2_amd64 
NAME
Graphics::TIFF - Perl extension for the libtiff library
VERSION
19
SYNOPSIS
Perl bindings for the libtiff library. This module allows you to access TIFF images in a
Perlish and object-oriented way, freeing you from the casting and memory management in C,
yet remaining very close in spirit to original API.
The following snippet can be used to read the image data from a TIFF:
use Graphics::TIFF ':all';
my $tif = Graphics::TIFF->Open( 'test.tif', 'r' );
my $stripsize = $tif->StripSize;
for my $stripnum ( 0 .. $tif->NumberOfStrips - 1 ) {
my $buffer = $tif->ReadEncodedStrip( $stripnum, $stripsize );
# do something with $buffer
}
$tif->Close;
DESCRIPTION
The Graphics::TIFF module allows a Perl developer to access TIFF images. Find out more
about libtiff at <http://www.libtiff.org>.
SUBROUTINES/METHODS
Graphics::TIFF->get_version
Returns an array with the LIBTIFF_VERSION_(MAJOR|MINOR|MICRO) versions:
join('.',Graphics::TIFF->get_version)
Graphics::TIFF->get_version_scalar
Returns an scalar with the LIBTIFF_VERSION_(MAJOR|MINOR|MICRO) versions combined as per
the Perl version numbering, i.e. libtiff 4.0.6 gives 4.000006. This allows simple version
comparisons.
Graphics::TIFF->GetVersion
Returns a string with the format "LIBTIFF, Version MAJOR.MINOR.MICRO"
Graphics::TIFF->IsCODECConfigured(compression)
Returns a boolean if libtiff was configured with the given compression method. See the
possible values for the TIFFTAG_COMPRESSION tag for valid compression methods.
Graphics::TIFF->Open(filename, flags)
Returns a TIFF object. 'r' and 'w' are valid flags.
$tif->Close
Closes the tiff given TIFF object.
$tif->FileName
Returns the filename associated with the given TIFF object.
$tif->ReadDirectory
Read the next directory in the specified file and make it the current directory.
Applications only need to call ReadDirectory to read multiple subfiles in a single TIFF
file - the first directory in a file is automatically read when Open is called.
Notes
If the library is compiled with STRIPCHOP_SUPPORT enabled, then images that have a single
uncompressed strip or tile of data are automatically treated as if they were made up of
multiple strips or tiles of approximately 8 kilobytes each. This operation is done only
in-memory; it does not alter the contents of the file. However, the construction of the
''chopped strips'' is visible to the application through the number of strips [tiles]
returned by NumberOfStrips [NumberOfTiles].
Return Values
If the next directory was successfully read, 1 is returned. Otherwise, 0 is returned if an
error was encountered, or if there are no more directories to be read.
$tif->WriteDirectory
WriteDirectory will write the contents of the current directory to the file and setup to
create a new subfile in the same file. Applications only need to call WriteDirectory when
writing multiple subfiles to a single TIFF file. WriteDirectory is automatically called
by Close and Flush to write a modified directory if the file is open for writing.
The RewriteDirectory function operates similarly to WriteDirectory, but can be called with
directories previously read or written that already have an established location in the
file. It will rewrite the directory, but instead of place it at it's old location (as
TIFFWriteDirectory would) it will place them at the end of the file, correcting the
pointer from the preceding directory or file header to point to it's new location. This is
particularly important in cases where the size of the directory and pointed to data has
grown, so it won't fit in the space available at the old location.
The CheckpointDirectory writes the current state of the tiff directory into the file to
make what is currently in the file readable. Unlike WriteDirectory, CheckpointDirectory
does not free up the directory data structures in memory, so they can be updated (as
strips/tiles are written) and written again. Reading such a partial file you will at worst
get a tiff read error for the first strip/tile encountered that is incomplete, but you
will at least get all the valid data in the file before that. When the file is complete,
just use WriteDirectory as usual to finish it off cleanly.
Return Values
1 is returned when the contents are successfully written to the file. Otherwise, 0 is
returned if an error was encountered when writing the directory contents.
$tif->ReadEXIFDirectory(diroff)
Required before reading EXIF tags.
$tif->NumberOfDirectories
Returns the number of directory in the given TIFF object.
$tif->SetDirectory(dirnum)
Changes the current directory and reads its contents with ReadDirectory. The parameter
dirnum specifies the subfile/directory as an integer number, with the first directory
numbered zero.
Return Values
On successful return 1 is returned. Otherwise, 0 is returned if dirnum or diroff specifies
a non-existent directory, or if an error was encountered while reading the directory's
contents.
$tif->SetSubDirectory(diroff)
Acts like SetDirectory, except the directory is specified as a file offset instead of an
index; this is required for accessing subdirectories linked through a SubIFD tag.
$tif->GetField(tag)
Returns the value of a tag or pseudo-tag associated with the the current directory of the
open TIFF file tif. (A pseudo-tag is a parameter that is used to control the operation of
the TIFF library but whose value is not read or written to the underlying file.) The file
must have been previously opened with Open. The type and number of values returned is
dependent on the tag being requested.
The tags understood by libtiff are shown below. Consult the TIFF specification for
information on the meaning of each tag and their possible values.
TIFFTAG_ARTIST TIFFTAG_BADFAXLINES TIFFTAG_BITSPERSAMPLE TIFFTAG_CLEANFAXDATA
TIFFTAG_COLORMAP TIFFTAG_COMPRESSION (COMPRESSION_NONE COMPRESSION_CCITTRLE
COMPRESSION_CCITTFAX3 COMPRESSION_CCITT_T4 COMPRESSION_CCITTFAX4 COMPRESSION_CCITT_T6
COMPRESSION_LZW COMPRESSION_OJPEG COMPRESSION_JPEG COMPRESSION_T85 COMPRESSION_T43
COMPRESSION_NEXT COMPRESSION_CCITTRLEW COMPRESSION_PACKBITS COMPRESSION_THUNDERSCAN
COMPRESSION_IT8CTPAD COMPRESSION_IT8LW COMPRESSION_IT8MP COMPRESSION_IT8BL
COMPRESSION_PIXARFILM COMPRESSION_PIXARLOG COMPRESSION_DEFLATE COMPRESSION_ADOBE_DEFLATE
COMPRESSION_DCS COMPRESSION_JBIG COMPRESSION_SGILOG COMPRESSION_SGILOG24
COMPRESSION_JP2000 COMPRESSION_LZMA) TIFFTAG_CONSECUTIVEBADFAXLINES TIFFTAG_COPYRIGHT
TIFFTAG_DATATYPE TIFFTAG_DATETIME TIFFTAG_DOCUMENTNAME TIFFTAG_DOTRANGE
TIFFTAG_EXTRASAMPLES (EXTRASAMPLE_UNSPECIFIED EXTRASAMPLE_ASSOCALPHA
EXTRASAMPLE_UNASSALPHA) TIFFTAG_FAXMODE TIFFTAG_FAXFILLFUNC TIFFTAG_FILLORDER
(FILLORDER_MSB2LSB FILLORDER_LSB2MSB) TIFFTAG_GROUP3OPTIONS (GROUP3OPT_2DENCODING
GROUP3OPT_UNCOMPRESSED GROUP3OPT_FILLBITS) TIFFTAG_GROUP4OPTIONS (GROUP4OPT_UNCOMPRESSED)
TIFFTAG_HALFTONEHINTS TIFFTAG_HOSTCOMPUTER TIFFTAG_IMAGEDEPTH TIFFTAG_IMAGEDESCRIPTION
TIFFTAG_IMAGELENGTH TIFFTAG_IMAGEWIDTH TIFFTAG_INKNAMES TIFFTAG_INKSET (INKSET_CMYK
INKSET_MULTIINK) TIFFTAG_JPEGTABLES TIFFTAG_JPEGQUALITY TIFFTAG_JPEGCOLORMODE
(JPEGCOLORMODE_RAW JPEGCOLORMODE_RGB) TIFFTAG_JPEGPROC (JPEGPROC_BASELINE
JPEGPROC_LOSSLESS) TIFFTAG_JPEGTABLESMODE (JPEGTABLESMODE_QUANT JPEGTABLESMODE_HUFF)
TIFFTAG_MAKE TIFFTAG_MATTEING TIFFTAG_MAXSAMPLEVALUE TIFFTAG_MINSAMPLEVALUE TIFFTAG_MODEL
TIFFTAG_ORIENTATION (ORIENTATION_TOPLEFT ORIENTATION_TOPRIGHT ORIENTATION_BOTRIGHT
ORIENTATION_BOTLEFT ORIENTATION_LEFTTOP ORIENTATION_RIGHTTOP ORIENTATION_RIGHTBOT
ORIENTATION_LEFTBOT) TIFFTAG_OSUBFILETYPE (OFILETYPE_IMAGE OFILETYPE_REDUCEDIMAGE
OFILETYPE_PAGE) TIFFTAG_PAGENAME TIFFTAG_PAGENUMBER TIFFTAG_PHOTOMETRIC
(PHOTOMETRIC_MINISWHITE PHOTOMETRIC_MINISBLACK PHOTOMETRIC_RGB PHOTOMETRIC_PALETTE
PHOTOMETRIC_MASK PHOTOMETRIC_SEPARATED PHOTOMETRIC_YCBCR PHOTOMETRIC_CIELAB
PHOTOMETRIC_ICCLAB PHOTOMETRIC_ITULAB PHOTOMETRIC_LOGL PHOTOMETRIC_LOGLUV)
TIFFTAG_PLANARCONFIG (PLANARCONFIG_CONTIG PLANARCONFIG_SEPARATE) TIFFTAG_PREDICTOR
(PREDICTOR_NONE PREDICTOR_HORIZONTAL PREDICTOR_FLOATINGPOINT)
TIFFTAG_PRIMARYCHROMATICITIES TIFFTAG_REFERENCEBLACKWHITE TIFFTAG_RESOLUTIONUNIT
(RESUNIT_NONE RESUNIT_INCH RESUNIT_CENTIMETER) TIFFTAG_ROWSPERSTRIP TIFFTAG_SAMPLEFORMAT
(SAMPLEFORMAT_UINT SAMPLEFORMAT_INT SAMPLEFORMAT_IEEEFP SAMPLEFORMAT_VOID
SAMPLEFORMAT_COMPLEXINT SAMPLEFORMAT_COMPLEXIEEEFP) TIFFTAG_SAMPLESPERPIXEL
TIFFTAG_SMAXSAMPLEVALUE TIFFTAG_SMINSAMPLEVALUE TIFFTAG_SOFTWARE TIFFTAG_STONITS
TIFFTAG_STRIPBYTECOUNTS TIFFTAG_STRIPOFFSETS TIFFTAG_SUBFILETYPE (FILETYPE_REDUCEDIMAGE
FILETYPE_PAGE FILETYPE_MASK) TIFFTAG_SUBIFD TIFFTAG_TARGETPRINTER TIFFTAG_THRESHHOLDING
TIFFTAG_TILEBYTECOUNTS TIFFTAG_TILEDEPTH TIFFTAG_TILELENGTH TIFFTAG_TILEOFFSETS
TIFFTAG_TILEWIDTH TIFFTAG_TRANSFERFUNCTION TIFFTAG_WHITEPOINT TIFFTAG_XPOSITION
TIFFTAG_XRESOLUTION TIFFTAG_YCBCRCOEFFICIENTS TIFFTAG_YCBCRPOSITIONING
TIFFTAG_YCBCRSUBSAMPLING TIFFTAG_YPOSITION TIFFTAG_YRESOLUTION TIFFTAG_ICCPROFILE
$tif->GetFieldDefaulted(tag)
Identical to GetField, except that if a tag is not defined in the current directory and it
has a default value, then the default value is returned.
$tif->SetField(tag, ...)
Sets the value of a field or pseudo-tag in the current directory associated with the open
TIFF file tif. Set GetField for Possible values for# tag.
$tif->IsTiled
Returns a non-zero value if the image data has a tiled organisation. Zero is returned if
the image data is organised in strips.
$tif->ScanlineSize
Returns the size in bytes of a row of data as it would be returned in a call to
ReadScanline, or as it would be expected in a call to WriteScanline.
$tif->StripSize
Returns the equivalent size for a strip of data as it would be returned in a call to
ReadEncodedStrip or as it would be expected in a call to WriteEncodedStrip.
$tif->NumberOfStrips
Returns the number of strips in the image.
$tif->TileSize
Returns the equivalent size for a tile of data as it would be returned in a call to
ReadTile or as it would be expected in a call to WriteTile.
$tif->TileRowSize
Returns the number of bytes of a row of data in a tile.
$tif->ComputeStrip(row, sample)
Returns the strip that contains the specified coordinates. A valid strip is always
returned; out-of-range coordinate values are clamped to the bounds of the image. The row
parameter is always used in calculating a strip. The sample parameter is used only if data
are organised in separate planes (PlanarConfiguration=2).
$tif->ReadEncodedStrip(strip, size)
Returns a buffer of up to size bytes of decompressed information.
The value of strip is a ``raw strip number.'' That is, the caller must take into account
whether or not the data are organised in separate planes (PlanarConfiguration=2). To read
a full strip of data the data buffer should typically be at least as large as the number
returned by StripSize.
The library attempts to hide bit- and byte-ordering differences between the image and the
native machine by converting data to the native machine order. Bit reversal is done if
the FillOrder tag is opposite to the native machine bit order. 16- and 32-bit samples are
automatically byte-swapped if the file was written with a byte order opposite to the
native machine byte order.
$tif->WriteEncodedStrip(strip, data, size)
Compress size bytes of raw data from buf and write the result to the specified strip;
replacing any previously written data. Note that the value of strip is a ``raw strip
number.'' That is, the caller must take into account whether or not the data are organised
in separate places (PlanarConfiguration=2).
The library writes encoded data using the native machine byte order. Correctly implemented
TIFF readers are expected to do any necessary byte-swapping to correctly process image
data with BitsPerSample greater than 8.
The strip number must be valid according to the current settings of the ImageLength and
RowsPerStrip tags. An image may be dynamically grown by increasing the value of
ImageLength prior to each call to TIFFWriteEncodedStrip.
-1 is returned if an error was encountered. Otherwise, the value of size is returned.
$tif->ReadRawStrip(strip, size)
Returns the contents of the specified strip. Note that the value of strip is a ''raw strip
number.'' That is, the caller must take into account whether or not the data is organised
in separate planes (PlanarConfiguration=2). To read a full strip of data the data buffer
should typically be at least as large as the number returned by StripSize.
$tif->ReadTile(x, y, z, s)
Returns the data for the tile containing the specified coordinates. The data is returned
decompressed and, typically, in the native byte- and bit-ordering, but are otherwise
packed (see further below). The buffer must be large enough to hold an entire tile of
data. Applications should call the routine TIFFTileSize to find out the size (in bytes) of
a tile buffer. The x and y parameters are always used by ReadTile. The z parameter is used
if the image is deeper than 1 slice (ImageDepth>1). The sample parameter is used only if
data are organised in separate planes (PlanarConfiguration=2).
The library attempts to hide bit- and byte-ordering differences between the image and the
native machine by converting data to the native machine order. Bit reversal is done if the
FillOrder tag is opposite to the native machine bit order. 16- and 32-bit samples are
automatically byte-swapped if the file was written with a byte order opposite to the
native machine byte order.
$tif->CurrentDirectory()
Return an index number of the current directory in the specified TIFF file.
$tif->PrintDirectory(file, flags)
Prints a description of the current directory in the specified TIFF file to the standard
I/O output stream fd. The flags parameter is used to control the level of detail of the
printed information, and is a bitwise or of the following values:
TIFFPRINT_NONE TIFFPRINT_STRIPS TIFFPRINT_CURVES TIFFPRINT_COLORMAP TIFFPRINT_JPEGQTABLES
TIFFPRINT_JPEGACTABLES TIFFPRINT_JPEGDCTABLES
Graphics::TIFF::ReverseBits(data, size)
Replaces each byte in data with the equivalent bit-reversed value. This operation is done
with a lookup table.
DIAGNOSTICS
CONFIGURATION AND ENVIRONMENT
DEPENDENCIES
Runtime
The runtime dependencies are just libtiff itself. In Windows this is satisfied by
Alien::libtiff.
Build
The build dependencies are additionally the development headers for libtiff and Perl.
Test
In addition to the above, the Perl module Image::Magick is required to run some of the
tests.
INCOMPATIBILITIES
BUGS AND LIMITATIONS
SEE ALSO
The LIBTIFF Standard Reference <http://www.libtiff.org/libtiff.html> is a handy companion.
The Perl bindings follow the C API very closely, and the C reference documentation should
be considered the canonical source.
AUTHOR
Jeffrey Ratcliffe, <jffry@posteo.net>
LICENSE AND COPYRIGHT
Copyright (C) 2017--2022 by Jeffrey Ratcliffe
This library is free software; you can redistribute it and/or modify it under the same
terms as Perl itself, either Perl version 5.8.5 or, at your option, any later version of
Perl 5 you may have available.