tiffreadtile.3t

tiff文件开发库

.\" $Header: /cvsroot/osrs/libtiff/man/TIFFReadTile.3t,v 1.1.1.1 1999/07/27 21:50:27 mike Exp $
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.\" Copyright (c) 1988-1997 Sam Leffler
.\" Copyright (c) 1991-1997 Silicon Graphics, Inc.
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.if n .po 0
.TH TIFFReadTile 3T "December 16, 1991"
.SH NAME
TIFFReadTile \- read and decode a tile of data from an open
.SM TIFF
file
.SH SYNOPSIS
.B "#include <tiffio.h>"
.br
.B "tsize_t TIFFReadTile(TIFF* tif, tdata_t buf, uint32 x, uint32 y, uint32 z, tsample_t sample)"
.SH DESCRIPTION
Return the data for the tile
.I containing
the specified coordinates.
The data placed in
.I buf
are 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
.IR TIFFTileSize
to find out the size (in bytes) of a tile buffer.
The
.I x
and
.I y
parameters are always used by
.IR TIFFReadTile .
The
.I z
parameter is used if the image is deeper than 1 slice (\c
.IR ImageDepth >1).
The
.I sample
parameter is used only if data are organized in separate planes (\c
.IR PlanarConfiguration =2).
.SH NOTES
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
.I 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,
.SH "RETURN VALUES"
.IR TIFFReadTile
returns \-1 if it detects an error; otherwise the number of
bytes in the decoded tile is returned.
.SH DIAGNOSTICS
All error messages are directed to the
.IR TIFFError (3T)
routine.
.SH "SEE ALSO"
.IR libtiff (3T),
.IR TIFFCheckTile (3T),
.IR TIFFComputeTile (3T),
.IR TIFFOpen (3T),
.IR TIFFReadEncodedTile (3T),
.IR TIFFReadRawTile (3T)