INTRO

libtiff − introduction to libtiff, a library for reading and writing TIFF files

#include <tiffio.h>

cc file.c -ltiff

libtiff is a library for reading and writing data files encoded with the Tag Image File format, Revision 6.0 (or revision 5.0 or revision 4.0). This file format is suitable for archiving multi-color and monochromatic image data.

The library supports several compression algorithms, as indicated by the Compression field, including: no compression (1), CCITT 1D Huffman compression (2), CCITT Group 3 Facsimile compression (3), CCITT Group 4 Facsimile compression (4), Lempel-Ziv & Welch compression (5), baseline JPEG compression (7), word-aligned 1D Huffman compression (32771), and PackBits compression (32773). In addition, several nonstandard compression algorithms are supported: the 4-bit compression algorithm used by the ThunderScan program (32809) (decompression only), NeXT’s 2-bit compression algorithm (32766) (decompression only), an experimental LZ-style algorithm known as Deflate (32946), and an experimental CIE LogLuv compression scheme designed for images with high dynamic range (32845 for LogL and 32845 for LogLuv). Directory information may be in either little- or big-endian byte order−byte swapping is automatically done by the library. Data bit ordering may be either Most Significant Bit ( MSB ) to Least Significant Bit ( LSB ) or LSB to MSB. Finally, the library does not support files in which the BitsPerSample, Compression, MinSampleValue, or MaxSampleValue fields are defined differently on a per-sample basis (in Rev. 6.0 the Compression tag is not defined on a per-sample basis, so this is immaterial).

The library makes extensive use of C typedefs to promote portability. Two sets of typedefs are used, one for communication with clients of the library and one for internal data structures and parsing of the TIFF format. The following typedefs are exposed to users either through function definitions or through parameters passed through the varargs interfaces.

typedef unsigned short uint16;

16-bit unsigned integer

typedef unsigned <thing> uint32;

32-bit unsigned integer

typedef unsigned int ttag_t;

directory tag

typedef uint16 tdir_t;

directory index

typedef uint16 tsample_t;

sample number

typedef uint32 tstrip_t;

strip number

typedef uint32 ttile_t;

tile number

typedef int32 tsize_t;

i/o size in bytes

typedef void* tdata_t;

image data ref

typedef void* thandle_t;

client data handle

typedef int32 toff_t;

file offset

Note that tstrip_t, ttile_t, and tsize_t are constrained to be no more than 32-bit quantities by 32-bit fields they are stored in in the TIFF image. Likewise tsample_t is limited by the 16-bit field used to store the SamplesPerPixel tag. tdir_t constrains the maximum number of IFDs that may appear in an image and may be an arbitrary size (w/o penalty). ttag_t must be either int, unsigned int, pointer, or double because the library uses a varargs interface and ANSI C restricts the type of the parameter before an ellipsis to be a promoted type. toff_t is defined as int32 because TIFF file offsets are (unsigned) 32-bit quantities. A signed value is used because some interfaces return −1 on error. Finally, note that user-specified data references are passed as opaque handles and only cast at the lowest layers where their type is presumed.

The following routines are part of the library. Consult specific manual pages for details on their operation; on most systems doing ‘‘man function-name’’ will work.

TIFFCheckpointDirectory

writes the current state of the directory

TIFFCheckTile

very x,y,z,sample is within image

TIFFCIELabToRGBInit

initialize CIE L*a*b* 1976 to RGB conversion state

TIFFCIELabToXYZ

perform CIE L*a*b* 1976 to CIE XYZ conversion

TIFFClientOpen

open a file for reading or writing

TIFFClose

close an open file

TIFFComputeStrip

return strip containing y,sample

TIFFComputeTile

return tile containing x,y,z,sample

TIFFCurrentDirectory

return index of current directory

TIFFCurrentRow

return index of current scanline

TIFFCurrentStrip

return index of current strip

TIFFCurrentTile

return index of current tile

TIFFDataWidth

return the size of TIFF data types

TIFFError

library error handler

TIFFFdOpen

open a file for reading or writing

TIFFFileName

return name of open file

TIFFFileno

return open file descriptor

TIFFFindCODEC

find standard codec for the specific scheme

TIFFFlush

flush all pending writes

TIFFFlushData

flush pending data writes

TIFFGetBitRevTable

return bit reversal table

TIFFGetField

return tag value in current directory

TIFFGetFieldDefaulted

return tag value in current directory

TIFFGetMode

return open file mode

TIFFGetVersion

return library version string

TIFFIsCODECConfigured

check, whether we have working codec

TIFFIsMSB2LSB

return true if image data is being returned

with bit 0 as the most significant bit

TIFFIsTiled

return true if image data is tiled

TIFFIsByteSwapped

return true if image data is byte-swapped

TIFFNumberOfStrips

return number of strips in an image

TIFFNumberOfTiles

return number of tiles in an image

TIFFOpen

open a file for reading or writing

TIFFPrintDirectory

print description of the current directory

TIFFReadBufferSetup

specify i/o buffer for reading

TIFFReadDirectory

read the next directory

TIFFReadEncodedStrip

read and decode a strip of data

TIFFReadEncodedTile

read and decode a tile of data

TIFFReadRawStrip

read a raw strip of data

TIFFReadRawTile

read a raw tile of data

TIFFReadRGBAImage

read an image into a fixed format raster

TIFFReadScanline

read and decode a row of data

TIFFReadTile

read and decode a tile of data

TIFFRegisterCODEC

override standard codec for the specific scheme

TIFFReverseBits

reverse bits in an array of bytes

TIFFRGBAImageBegin

setup decoder state for TIFFRGBAImageGet

TIFFRGBAImageEnd

release TIFFRGBAImage decoder state

TIFFRGBAImageGet

read and decode an image

TIFFRGBAImageOK

is image readable by TIFFRGBAImageGet

TIFFScanlineSize

return size of a scanline

TIFFSetDirectory

set the current directory

TIFFSetSubDirectory

set the current directory

TIFFSetErrorHandler

set error handler function

TIFFSetField

set a tag’s value in the current directory

TIFFSetWarningHandler

set warning handler function

TIFFStripSize

returns size of a strip

TIFFRawStripSize

returns the number of bytes in a raw strip

TIFFSwabShort

swap bytes of short

TIFFSwabLong

swap bytes of long

TIFFSwabArrayOfShort

swap bytes of an array of shorts

TIFFSwabArrayOfLong

swap bytes of an array of longs

TIFFTileRowSize

return size of a row in a tile

TIFFTileSize

return size of a tile

TIFFUnRegisterCODEC

unregisters the codec

TIFFVGetField

return tag value in current directory

TIFFVGetFieldDefaulted

return tag value in current directory

TIFFVSetField

set a tag’s value in the current directory

TIFFVStripSize

returns the number of bytes in a strip

TIFFWarning

library warning handler

TIFFWriteDirectory

write the current directory

TIFFWriteEncodedStrip

compress and write a strip of data

TIFFWriteEncodedTile

compress and write a tile of data

TIFFWriteRawStrip

write a raw strip of data

TIFFWriteRawTile

write a raw tile of data

TIFFWriteScanline

write a scanline of data

TIFFWriteTile

compress and write a tile of data

TIFFXYZToRGB

perform CIE XYZ to RGB conversion

TIFFYCbCrToRGBInit

initialize YCbCr to RGB conversion state

TIFFYCbCrtoRGB

perform YCbCr to RGB conversion

Auxiliary functions:

_TIFFfree

free memory buffer

_TIFFmalloc

dynamically allocate memory buffer

_TIFFmemcmp

compare contents of the memory buffers

_TIFFmemcpy

copy contents of the one buffer to another

_TIFFmemset

fill memory buffer with a constant byte

_TIFFrealloc

dynamically reallocate memory buffer

The table below lists the TIFF tags that are recognized and handled by the library. If no use is indicated in the table, then the library reads and writes the tag, but does not use it internally. Note that some tags are meaningful only when a particul