TIFFREADSCANLINE(3tiff) LibTIFF TIFFREADSCANLINE(3tiff)
TIFFReadScanline - read and decode a scanline of data from an open
TIFF file
#include <tiffio.h>
int TIFFReadScanline(TIFF *tif, void *buf, uint32_t row, uint16_t
sample)
Read the data for the specified row into the (user supplied) data
buffer buf. The data are returned decompressed and, in the native
byte- and bit-ordering, but are otherwise packed (see further 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 are 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 done if the 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,
In C++ the sample parameter defaults to 0.
TIFFReadScanline() returns -1 if it detects an error; otherwise 1 is
returned.
All error messages are directed to the TIFFErrorExtR() routine.
"Compression algorithm does not support random access":
Data was requested in a non-sequential order from a file that uses
a compression algorithm and that has RowsPerStrip 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.
Reading subsampled YCbCR data does not work correctly because, for
PlanarConfiguration = 2, the size of a scanline is not calculated on
a per-sample basis, and for PlanarConfiguration = 1, the library does
not unpack the block-interleaved samples; use the strip- and
tile-based interfaces to read these formats.
TIFFOpen (3tiff), TIFFReadEncodedStrip (3tiff), TIFFReadRawStrip
(3tiff), libtiff (3tiff)
LibTIFF contributors
1988-2025, LibTIFF contributors
4.7 March 7, 2026 TIFFREADSCANLINE(3tiff)
NAME
TIFFReadScanline - read and decode a scanline of data from an open
TIFF file
SYNOPSIS
#include <tiffio.h>
int TIFFReadScanline(TIFF *tif, void *buf, uint32_t row, uint16_t
sample)
DESCRIPTION
Read the data for the specified row into the (user supplied) data
buffer buf. The data are returned decompressed and, in the native
byte- and bit-ordering, but are otherwise packed (see further 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 are organized in separate planes (PlanarConfiguration = 2).
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 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,
In C++ the sample parameter defaults to 0.
RETURN VALUES
TIFFReadScanline() returns -1 if it detects an error; otherwise 1 is
returned.
DIAGNOSTICS
All error messages are directed to the TIFFErrorExtR() routine.
"Compression algorithm does not support random access":
Data was requested in a non-sequential order from a file that uses
a compression algorithm and that has RowsPerStrip 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.
BUGS
Reading subsampled YCbCR data does not work correctly because, for
PlanarConfiguration = 2, the size of a scanline is not calculated on
a per-sample basis, and for PlanarConfiguration = 1, the library does
not unpack the block-interleaved samples; use the strip- and
tile-based interfaces to read these formats.
SEE ALSO
TIFFOpen (3tiff), TIFFReadEncodedStrip (3tiff), TIFFReadRawStrip
(3tiff), libtiff (3tiff)
AUTHOR
LibTIFF contributors
COPYRIGHT
1988-2025, LibTIFF contributors
4.7 March 7, 2026 TIFFREADSCANLINE(3tiff)