TIFFWriteScanline(3T)TIFFWriteScanline(3T)NAMETIFFWriteScanline - write a scanline to an open TIFF file
SYNOPSIS
#include <tiffio.h>
int TIFFWriteScanline(TIFF* tif, tdata_t buf, uint32 row,
tsample_t sample)
DESCRIPTION
Write data to a file at the specified row. The sample
parameter is used only if data are organized in separate
planes (PlanarConfiguration=2). The data are assumed to
be uncompressed and in the native bit- and byte-order of
the host machine. The data written to the file is com-
pressed according to the compression scheme of the current
TIFF directory (see further below). If the current scan-
line is past the end of the current subfile, the Image-
Length field is automatically increased to include the
scanline (except for PlanarConfiguration=2, where the
ImageLength cannot be changed once the first data are
written). If the ImageLength is increased, the StripOff-
sets and StripByteCounts fields are similarly enlarged to
reflect data written past the previous end of image.
NOTES
The library writes encoded data using the native machine
byte order. Correctly implemented TIFF readers are
expected to do any necessary byte-swapping to correctly
process image data with BitsPerSample greater than 8. The
library attempts to hide bit-ordering differences between
the image and the native machine by converting data from
the native machine order.
In C++ the sample parameter defaults to 0.
Once data are written to a file for the current directory,
the values of certain tags may not be altered; see TIFF-
SetField(3T) for more information.
It is not possible to write scanlines to a file that uses
a tiled organization. The routine TIFFIsTiled can be used
to determine if the file is organized as tiles or strips.
RETURN VALUESTIFFWriteScanline returns -1 if it immediately detects an
error and 1 for a successful write.
DIAGNOSTICS
All error messages are directed to the TIFFError(3T) rou-
tine.
%s: File not open for writing . The file was opened for
reading, not writing.
December 16, 1991 1
TIFFWriteScanline(3T)TIFFWriteScanline(3T)
Can not write scanlines to a tiled image. An attempt was
made to write a scanline to a tiled image. The image is
assumed to be organized in tiles because the TileWidth and
TileLength tags have been set with TIFFSetField(3T).
Compression algorithm does not support random access.
Data was written in a non-sequential order to a file that
uses a compression algorithm and that has RowsPerStrip
greater than one. That is, data in the image is to be
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
written as entire strips, sequentially by rows, or the
value of RowsPerStrip should be set to one.
%s: Must set "ImageWidth" before writing data. The
image's width has not be set before the first write. See
TIFFSetField(3T) for information on how to do this.
%s: Must set "PlanarConfiguration" before writing data.
The organization of data has not be defined before the
first write. See TIFFSetField(3T) for information on how
to do this.
Can not change "ImageLength" when using separate planes.
Separate image planes are being used (PlanarConfigura-
tion=2), but the number of rows has not been specified
before the first write. The library supports the dynamic
growth of an image only when data are organized in a con-
tiguous manner (PlanarConfiguration=1).
%d: Sample out of range, max %d. The sample parameter was
greater than the value of the SamplesPerPixel tag.
%s: No space for strip arrays . There was not enough
space for the arrays that hold strip offsets and byte
counts.
BUGS
Writing 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 Planar-
Configuration=1 the library does not pack the block-inter-
leaved samples.
SEE ALSOlibtiff(3T), TIFFOpen(3T), TIFFWriteEncodedStrip(3T),
TIFFWriteRawStrip(3T)
December 16, 1991 2
