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80ed523f | 1 | .\" $Id: TIFFReadScanline.3tiff,v 1.2 2005-11-02 11:07:18 dron Exp $ |
8414a40c VZ |
2 | .\" |
3 | .\" Copyright (c) 1988-1997 Sam Leffler | |
4 | .\" Copyright (c) 1991-1997 Silicon Graphics, Inc. | |
5 | .\" | |
6 | .\" Permission to use, copy, modify, distribute, and sell this software and | |
7 | .\" its documentation for any purpose is hereby granted without fee, provided | |
8 | .\" that (i) the above copyright notices and this permission notice appear in | |
9 | .\" all copies of the software and related documentation, and (ii) the names of | |
10 | .\" Sam Leffler and Silicon Graphics may not be used in any advertising or | |
11 | .\" publicity relating to the software without the specific, prior written | |
12 | .\" permission of Sam Leffler and Silicon Graphics. | |
13 | .\" | |
14 | .\" THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND, | |
15 | .\" EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY | |
16 | .\" WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. | |
17 | .\" | |
18 | .\" IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR | |
19 | .\" ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND, | |
20 | .\" OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, | |
21 | .\" WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF | |
22 | .\" LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE | |
23 | .\" OF THIS SOFTWARE. | |
24 | .\" | |
25 | .if n .po 0 | |
26 | .TH TIFFReadScanline 3TIFF "October 15, 1995" "libtiff" | |
27 | .SH NAME | |
28 | TIFFReadScanline \- read and decode a scanline of data from an open | |
29 | .SM TIFF | |
30 | file | |
31 | .SH SYNOPSIS | |
32 | .B "#include <tiffio.h>" | |
33 | .sp | |
34 | .BI "int TIFFReadScanline(TIFF *" tif ", tdata_t " buf ", uint32 " row ", tsample_t " sample ")" | |
35 | .SH DESCRIPTION | |
36 | Read the data for the specified row into the (user supplied) data buffer | |
37 | .IR buf . | |
38 | The data are returned decompressed and, in the native byte- and bit-ordering, | |
39 | but are otherwise packed (see further below). The buffer must be large enough | |
40 | to hold an entire scanline of data. Applications should call the routine | |
41 | .IR TIFFScanlineSize | |
42 | to find out the size (in bytes) of a scanline buffer. | |
43 | The | |
44 | .I row | |
45 | parameter is always used by | |
46 | .IR TIFFReadScanline ; | |
47 | the | |
48 | .I sample | |
49 | parameter is used only if data are organized in separate planes (\c | |
50 | .IR PlanarConfiguration =2). | |
51 | .SH NOTES | |
52 | The library attempts to hide bit- and byte-ordering differences between the | |
53 | image and the native machine by converting data to the native machine order. | |
54 | Bit reversal is done if the | |
55 | .I FillOrder | |
56 | tag is opposite to the native machine bit order. 16- and 32-bit samples are | |
57 | automatically byte-swapped if the file was written with a byte order opposite | |
58 | to the native machine byte order, | |
59 | .PP | |
60 | In C++ the | |
61 | .I sample | |
62 | parameter defaults to 0. | |
63 | .SH "RETURN VALUES" | |
64 | .IR TIFFReadScanline | |
65 | returns \-1 if it detects an error; otherwise 1 is returned. | |
66 | .SH DIAGNOSTICS | |
67 | All error messages are directed to the | |
68 | .IR TIFFError (3TIFF) | |
69 | routine. | |
70 | .PP | |
71 | .BR "Compression algorithm does not support random access" . | |
72 | Data was requested in a non-sequential order from a file that uses a | |
73 | compression algorithm and that has | |
74 | .I RowsPerStrip | |
75 | greater than one. | |
76 | That is, data in the image is stored in a compressed form, and with multiple | |
77 | rows packed into a strip. In this case, the library does not support random | |
78 | access to the data. The data should either be accessed sequentially, or the | |
79 | file should be converted so that each strip is made up of one row of data. | |
80 | .SH BUGS | |
81 | Reading subsampled YCbCR data does not work correctly because, for | |
82 | .IR PlanarConfiguration =2 | |
83 | the size of a scanline is not calculated on a per-sample basis, and for | |
84 | .IR PlanarConfiguration =1 | |
85 | the library does not unpack the block-interleaved samples; use the strip- and | |
86 | tile-based interfaces to read these formats. | |
87 | .SH "SEE ALSO" | |
88 | .BR TIFFOpen (3TIFF), | |
89 | .BR TIFFReadEncodedStrip (3TIFF), | |
90 | .BR TIFFReadRawStrip (3TIFF), | |
91 | .BR libtiff (3TIFF) | |
92 | .PP | |
93 | Libtiff library home page: | |
94 | .BR http://www.remotesensing.org/libtiff/ |