--- name: "libtiff" section: "3t" platform: "linux" package: "libtiff3g-dev" version: "3.5.5-6.woody5" release: "Debian 3.0 (Woody)" platforms: ["linux"] url: "https://new.carta.tech/libtiff" --- # libtiff(3t) introduction to libtiff, a library for reading and writing TIFF files ## NAME libtiff - introduction to *libtiff*, a library for reading and writing TIFF files ## SYNOPSIS **#include \**\ cc file.c **-ltiff** ## DESCRIPTION *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). ## DATA TYPES 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 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. ## LIST OF ROUTINES The following routines are part of the library. Consult specific manual pages for details on their operation. The manual page names listed below are for systems where the full function names can not be encoded in the filesystem; on most systems doing \`\`man function-name'' will work. ``` Name Appears on Page Description TIFFCheckTile tile.3t very x,y,z,sample is within image TIFFClientOpen open.3t open a file for reading or writing TIFFClose close.3t close an open file TIFFComputeStrip strip.3t return strip containing y,sample TIFFComputeTile tile.3t return tile containing x,y,z,sample TIFFCurrentDirectory query.3t return index of current directory TIFFCurrentRow query.3t return index of current scanline TIFFCurrentStrip query.3t return index of current strip TIFFCurrentTile query.3t return index of current tile TIFFError error.3t library error handler TIFFFdOpen open.3t open a file for reading or writing TIFFFileName query.3t return name of open file TIFFFileno query.3t return open file descriptor TIFFFlush flush.3t flush all pending writes TIFFFlushData flush.3t flush pending data writes TIFFGetBitRevTable swab.3t return bit reversal table TIFFGetField getfield.3t return tag value in current directory TIFFGetFieldDefaulted getfield.3t return tag value in current directory TIFFGetMode query.3t return open file mode TIFFGetVersion query.3t return library version string TIFFIsTiled query.3t return true if image data is tiled TIFFIsByteSwapped query.3t return true if image data is byte-swapped TIFFNumberOfStrips strip.3t return number of strips in an image TIFFNumberOfTiles tile.3t return number of tiles in an image TIFFOpen open.3t open a file for reading or writing TIFFPrintDirectory print.3t print description of the current directory TIFFReadBufferSetup rdbuf.3t specify i/o buffer for reading TIFFReadDirectory readdir.3t read the next directory TIFFReadEncodedStrip rdestrip.3t read and decode a strip of data TIFFReadEncodedTile rdetile.3t read and decode a tile of data TIFFReadRawStrip rdrstrip.3t read a raw strip of data TIFFReadRawTile rdrtile.3t read a raw tile of data TIFFReadRGBAImage rdimage.3t read an image into a fixed format raster TIFFReadScanline readline.3t read and decode a row of data TIFFReadTile readtile.3t read and decode a tile of data TIFFReverseBits swab.3t reverse bits in an array of bytes TIFFRGBAImageBegin rgbaimage.3t setup decoder state for TIFFRGBAImageGet TIFFRGBAImageEnd rgbaimage.3t release TIFFRGBAImage decoder state TIFFRGBAImageGet rgbaimage.3t read and decode an image TIFFRGBAImageOK rgbaimage.3t is image readable by TIFFRGBAImageGet TIFFScanlineSize size.3t return size of a scanline TIFFSetDirectory setdir.3t set the current directory TIFFSetSubDirectory setdir.3t set the current directory TIFFSetErrorHandler error.3t set error handler function TIFFSetField setfield.3t set a tag's value in the current directory TIFFSetWarningHandler error.3t set warning handler function TIFFStripSize size.3t return size of a strip TIFFSwabShort swab.3t swap bytes of short TIFFSwabLong swab.3t swap bytes of long TIFFSwabArrayOfShort swab.3t swap bytes of an array of shorts TIFFSwabArrayOfLong swab.3t swap bytes of an array of longs TIFFTileRowSize size.3t return size of a row in a tile TIFFTileSize size.3t return size of a tile TIFFVGetField getfield.3t return tag value in current directory TIFFVGetFieldDefaulted getfield.3t return tag value in current directory TIFFVSetField setfield.3t set a tag's value in the current directory TIFFWarning warning.3t library warning handler TIFFWriteDirectory writedir.3t write the current directory TIFFWriteEncodedStrip wrestrip.3t compress and write a strip of data TIFFWriteEncodedTile wretile.3t compress and write a tile of data TIFFWriteRawStrip wrrstrip.3t write a raw strip of data TIFFWriteRawTile wrrtile.3t write a raw tile of data TIFFWriteScanline writeline.3t write a scanline of data TIFFWriteTile wrrtile.3t compress and write a tile of data ``` ## TAG USAGE 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 particular compression scheme is being used; e.g. *Group3Options* is only useful if *Compression* is set to CCITT Group 3 encoding. Tags of this sort are considered *codec-specific* tags and the library does not recognize them except when the *Compression* tag has been previously set to the relevant compression scheme. ``` Tag Name Value R/W Library Use/Notes Artist 315 R/W BadFaxLines 326 R/W BitsPerSample 258 R/W lots CellLength 265 parsed but ignored CellWidth 264 parsed but ignored CleanFaxData 327 R/W ColorMap 320 R/W ColorResponseUnit 300 parsed but ignored Compression 259 R/W choosing codec ConsecutiveBadFaxLines 328 R/W DataType 32996 R obsoleted by SampleFormat tag DateTime 306 R/W DocumentName 269 R/W DotRange 336 R/W ExtraSamples 338 R/W lots FaxRecvParams 34908 R/W FaxSubAddress 34909 R/W FaxRecvTime 34910 R/W FillOrder 266 R/W control bit order FreeByteCounts 289 parsed but ignored FreeOffsets 288 parsed but ignored GrayResponseCurve 291 parsed but ignored GrayResponseUnit 290 parsed but ignored Group3Options 292 R/W used by Group 3 codec Group4Options 293 R/W HostComputer 316 R/W ImageDepth 32997 R/W tile/strip calculations ImageDescription 270 R/W ImageLength 257 R/W lots ImageWidth 256 R/W lots InkNames 333 R/W InkSet 332 R/W JPEGTables 347 R/W used by JPEG codec Make 271 R/W Matteing 32995 R obsoleted by ExtraSamples tag MaxSampleValue 281 R/W MinSampleValue 280 R/W Model 272 R/W NewSubFileType 254 R/W called SubFileType in spec NumberOfInks 334 R/W Orientation 274 R/W PageName 285 R/W PageNumber 297 R/W PhotometricInterpretation 262 R/W used by Group 3 and JPEG codecs PlanarConfiguration 284 R/W data i/o Predictor 317 R/W used by LZW and Deflate codecs PrimaryChromacities 319 R/W ReferenceBlackWhite 532 R/W ResolutionUnit 296 R/W used by Group 3 codec RowsPerStrip 278 R/W data i/o SampleFormat 339 R/W SamplesPerPixel 277 R/W lots SMinSampleValue 340 R/W SMaxSampleValue 341 R/W Software 305 R/W StoNits 37439 R/W StripByteCounts 279 R/W data i/o StripOffsets 273 R/W data i/o SubFileType 255 R/W called OSubFileType in spec TargetPrinter 337 R/W Thresholding 263 R/W TileByteCounts 324 R/W data i/o TileDepth 32998 R/W tile/strip calculations TileLength 323 R/W data i/o TileOffsets 324 R/W data i/o TileWidth 322 R/W data i/o TransferFunction 301 R/W WhitePoint 318 R/W XPosition 286 R/W XResolution 282 R/W YCbCrCoefficients 529 R/W used by TIFFRGBAImage support YCbCrPositioning 531 R/W tile/strip size calulcations YCbCrSubsampling 530 R/W YPosition 286 R/W YResolution 283 R/W used by Group 3 codec ``` ## PSEUDO TAGS In addition to the normal TIFF tags the library supports a collection of tags whose values lie in a range outside the valid range of TIFF tags. These tags are termed *pseud-tags* and are used to control various codec-specific functions within the library. The table below summarizes the defined pseudo-tags. ``` Tag Name Codec R/W Library Use/Notes TIFFTAG_FAXMODE G3 R/W general codec operation TIFFTAG_FAXFILLFUNC G3/G4 R/W bitmap fill function TIFFTAG_JPEGQUALITY JPEG R/W compression quality control TIFFTAG_JPEGCOLORMODE JPEG R/W control colorspace conversions TIFFTAG_JPEGTABLESMODE JPEG R/W control contents of JPEGTables tag TIFFTAG_ZIPQUALITY Deflate R/W compression quality level TIFFTAG_PIXARLOGDATAFMT PixarLog R/W user data format TIFFTAG_PIXARLOGQUALITY PixarLog R/W compression quality level TIFFTAG_SGILOGDATAFMT SGILog R/W user data format ``` - **TIFFTAG\_FAXMODE** Control the operation of the Group 3 codec. Possible values (independent bits that can be combined by or'ing them together) are: FAXMODE\_CLASSIC (enable old-style format in which the RTC is written at the end of the last strip), FAXMODE\_NORTC (opposite of FAXMODE\_CLASSIC; also called FAXMODE\_CLASSF), FAXMODE\_NOEOL (do not write EOL codes at the start of each row of data), FAXMODE\_BYTEALIGN (align each encoded row to an 8-bit boundary), FAXMODE\_WORDALIGN (align each encoded row to an 16-bit boundary), The default value is dependent on the compression scheme; this pseudo-tag is used by the various G3 and G4 codecs to share code. - **TIFFTAG\_FAXFILLFUNC** Control the function used to convert arrays of black and white runs to packed bit arrays. This hook can be used to image decoded scanlines in multi-bit depth rasters (e.g. for display in colormap mode) or for other purposes. The default value is a pointer to a builtin function that images packed bilevel data. - **TIFFTAG\_IPTCNEWSPHOTO** Tag contaings image metadata per the IPTC newsphoto spec: Headline, captioning, credit, etc... Used by most wire services. - **TIFFTAG\_PHOTOSHOP** Tag contains Photoshop captioning information and metadata. Photoshop uses in parallel and redundantly alongside IPTCNEWSPHOTO information. - **TIFFTAG\_JPEGQUALITY** Control the compression quality level used in the baseline algorithm. Note that quality levels are in the range 0-100 with a default value of 75. - **TIFFTAG\_JPEGCOLORMODE** Control whether or not conversion is done between RGB and YCbCr colorspaces. Possible values are: JPEGCOLORMODE\_RAW (do not convert), and JPEGCOLORMODE\_RGB (convert to/from RGB) The default value is JPEGCOLORMODE\_RAW. - **TIFFTAG\_JPEGTABLESMODE** Control the information written in the *JPEGTables* tag. Possible values (independent bits that can be combined by or'ing them together) are: JPEGTABLESMODE\_QUANT (include quantization tables), and JPEGTABLESMODE\_HUFF (include Huffman encoding tables). The default value is JPEGTABLESMODE\_QUANT\|JPEGTABLESMODE\_HUFF. - **TIFFTAG\_ZIPQUALITY** Control the compression technique used by the Deflate codec. Quality levels are in the range 1-9 with larger numbers yielding better compression at the cost of more computation. The default quality level is 6 which yields a good time-space tradeoff. - **TIFFTAG\_PIXARLOGDATAFMT** Control the format of user data passed *in* to the PixarLog codec when encoding and passed *out* from when decoding. Possible values are: PIXARLOGDATAFMT\_8BIT for 8-bit unsigned pixels, PIXARLOGDATAFMT\_8BITABGR for 8-bit unsigned ABGR-ordered pixels, PIXARLOGDATAFMT\_11BITLOG for 11-bit log-encoded raw data, PIXARLOGDATAFMT\_12BITPICIO for 12-bit PICIO-compatible data, PIXARLOGDATAFMT\_16BIT for 16-bit signed samples, and PIXARLOGDATAFMT\_FLOAT for 32-bit IEEE floating point samples. - **TIFFTAG\_PIXARLOGQUALITY** Control the compression technique used by the PixarLog codec. This value is treated identically to TIFFTAG\_ZIPQUALITY; see the above description. - **TIFFTAG\_SGILOGDATAFMT** Control the format of client data passed *in* to the SGILog codec when encoding and passed *out* from when decoding. Possible values are: SGILOGDATAFMT\_FLTXYZ for converting between LogLuv and 32-bit IEEE floating valued XYZ pixels, SGILOGDATAFMT\_16BITLUV for 16-bit encoded Luv pixels, SGILOGDATAFMT\_32BITRAW and SGILOGDATAFMT\_24BITRAW for no conversion of data, SGILOGDATAFMT\_8BITRGB for returning 8-bit RGB data (valid only when decoding LogLuv-encoded data), SGILOGDATAFMT\_FLTY for converting between LogL and 32-bit IEEE floating valued Y pixels, SGILOGDATAFMT\_16BITL for 16-bit encoded L pixels, and SGILOGDATAFMT\_8BITGRY for returning 8-bit greyscale data (valid only when decoding LogL-encoded data). ## DIAGNOSTICS All error messages are directed through the *TIFFError* routine. By default messages are directed to **stderr** in the form: *module: message\\n.* Warning messages are likewise directed through the *TIFFWarning* routine. ## SEE ALSO [*fax2tiff*(1)](/fax2tiff/1.md), [*gif2tiff*(1)](/gif2tiff/1.md), [*pal2rgb*(1)](/pal2rgb/1.md), [*ppm2tiff*(1)](/ppm2tiff/1.md), [*rgb2ycbcr*(1)](/rgb2ycbcr/1.md), [*ras2tiff*(1)](/ras2tiff/1.md), [*sgi2tiff*(1)](/sgi2tiff/1.md), [*tiff2bw*(1)](/tiff2bw/1.md), [*tiffdither*(1)](/tiffdither/1.md), [*tiffdump*(1)](/tiffdump/1.md), [*tiffcp*(1)](/tiffcp/1.md), [*tiffcmp*(1)](/tiffcmp/1.md), [*tiffgt*(1)](/tiffgt/1.md), [*tiffinfo*(1)](/tiffinfo/1.md), [*tiffmedian*(1)](/tiffmedian/1.md), [*tiffsplit*(1)](/tiffsplit/1.md), [*tiffsv*(1)](/tiffsv/1.md), *Tag Image File Format Specification — Revision 6.0*, an Aldus Technical Memorandum. *The Spirit of TIFF Class F*, an appendix to the TIFF 5.0 specification prepared by Cygnet Technologies. ## BUGS The library does not support multi-sample images where some samples have different bits/sample. The library does not support random access to compressed data that is organized with more than one row per tile or strip. The library discards unknown tags. The library should do more validity checking of a directory's contents.