NAME

Graphics::TIFF - Perl extension for the libtiff library

VERSION

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).

$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

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

AUTHOR

Jeffrey Ratcliffe, <jffry@posteo.net>

LICENSE AND COPYRIGHT

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.