100 lines
3.7 KiB
Plaintext
100 lines
3.7 KiB
Plaintext
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.\" $Header: /cvs/maptools/cvsroot/libtiff/man/Attic/TIFFReadScanline.3t,v 1.1 1999-07-27 21:50:27 mike Exp $
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.\"
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.\" Copyright (c) 1988-1997 Sam Leffler
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.\" Copyright (c) 1991-1997 Silicon Graphics, Inc.
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.\"
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.\" Permission to use, copy, modify, distribute, and sell this software and
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.\" its documentation for any purpose is hereby granted without fee, provided
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.\" that (i) the above copyright notices and this permission notice appear in
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.\" all copies of the software and related documentation, and (ii) the names of
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.\" Sam Leffler and Silicon Graphics may not be used in any advertising or
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.\" publicity relating to the software without the specific, prior written
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.\" permission of Sam Leffler and Silicon Graphics.
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.\"
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.\" THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
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.\" EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
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.\" WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
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.\"
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.\" IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
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.\" ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
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.\" OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
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.\" WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
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.\" LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
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.\" OF THIS SOFTWARE.
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.\"
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.if n .po 0
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.TH TIFFReadScanline 3T "October 15, 1995"
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.SH NAME
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TIFFReadScanline \- read and decode a scanline of data from an open
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.SM TIFF
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file
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.SH SYNOPSIS
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.B "#include <tiffio.h>"
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.br
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.B "int TIFFReadScanline(TIFF* tif, tdata_t buf, uint32 row, tsample_t sample)"
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.SH DESCRIPTION
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Read the data for the specified row into the (user supplied)
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data buffer
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.IR buf .
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The data are returned decompressed and, in the native byte-
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and bit-ordering, but are otherwise packed (see further below).
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The buffer must be large enough to hold an entire scanline of data.
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Applications should call the routine
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.IR TIFFScanlineSize
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to find out the size (in bytes) of a scanline buffer.
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The
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.I row
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parameter is always used by
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.IR TIFFReadScanline ;
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the
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.I sample
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parameter is used only if data are organized in separate planes (\c
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.IR PlanarConfiguration =2).
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.SH NOTES
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The library attempts to hide bit- and byte-ordering differences
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between the image and the native machine by converting data
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to the native machine order.
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Bit reversal is done if the
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.I FillOrder
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tag is opposite to the native machine bit order.
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16- and 32-bit samples are automatically byte-swapped if the
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file was written with a byte order opposite to the native
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machine byte order,
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.PP
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In C++ the
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.I sample
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parameter defaults to 0.
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.SH "RETURN VALUES"
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.IR TIFFReadScanline
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returns \-1 if it detects an error; otherwise 1 is returned.
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.SH DIAGNOSTICS
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All error messages are directed to the
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.IR TIFFError (3T)
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routine.
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.PP
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.BR "Compression algorithm does not support random access" .
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Data was requested in a non-sequential order from a file that
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uses a compression algorithm and that has
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.I RowsPerStrip
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greater than one.
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That is, data in the image is stored in a compressed form,
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and with multiple rows packed into a strip.
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In this case, the library does not support random access to the data.
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The data should either be accessed sequentially, or the file
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should be converted so that each strip is made up of one row
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of data.
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.SH BUGS
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Reading subsampled YCbCR data does not work correctly
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because, for
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.IR PlanarConfiguration =2
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the size of a scanline is not calculated on a per-sample basis,
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and for
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.IR PlanarConfiguration =1
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the library does not unpack the block-interleaved samples; use
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the strip- and tile-based interfaces to read these formats.
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.SH "SEE ALSO"
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.IR libtiff (3T),
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.IR TIFFOpen (3T),
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.IR TIFFReadEncodedStrip (3T),
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.IR TIFFReadRawStrip (3T)
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