TIFFReadScanline(3tiff) TIFFReadScanline(3tiff)
NAME
TIFFReadScanline - read and decode a scanline of data from an open TIFF file
SYNOPSIS
#include <tiffio.h>
int TIFFReadScanline(TIFF* tif, tdata_t buf, uint32 row,
tsample_t sample)
Read the data for the specified row into the user-supplied data buffer.
EXTENDED DESCRIPTION
The data is returned decompressed and in the native byte- and bit-ordering, but is otherwise packed as described below. The buffer must be
large enough to hold an entire scanline of data. Applications should call the routine TIFFScanlineSize to find out the size in bytes of a
scanline buffer. The row parameter is always used by TIFFReadScanline. The sample parameter is used only if data is organized in separate
planes (PlanarConfiguration=2).
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 performed if the FillOrder tag is opposite to the native machine bit order. 16- and 32-bit samples are auto-
matically byte-swapped if the file was written with a byte order opposite to the native machine byte order.
Diagnostics
All error messages are directed to the TIFFError(3tiff) routine.
Compression algorithm doDataowasurequesteddin acnon-sequential order from a file that uses a compression algorithm and that has RowsPer-
Strip greater than one. That is, data in the image is stored in a compressed form, and with multiple rows packed
into a strip. In this case, the library does not support random access to the data. The data should either be
accessed sequentially, or the file should be converted so that each strip is made up of one row of data.
Returns -1 if an error was encountered. Otherwise, returns 1.
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWTiff |
+-----------------------------+-----------------------------+
|Interface stability |Uncommitted |
+-----------------------------+-----------------------------+
libtiff(3), TIFFOpen(3tiff), TIFFReadEncodedStrip(3tiff), TIFFReadRawStrip(3tiff)
In C++, the sample parameter defaults to 0.
Reading subsampled YCbCR data does not work correctly because:
o For PlanarConfiguration=2, the size of a scanline is not calculated on a per-sample basis.
o For PlanarConfiguration=1, the library does not unpack the block-interleaved samples.
Use the strip- and tile-based interfaces to read these formats.
This man page was originally written by Sam Leffler. Updated by Breda McColgan, Sun Microsystems Inc., 2004.
05 Apr 2004 TIFFReadScanline(3tiff)