TIFFWriteScanline
TIFFWriteScanline(3T) TIFFWriteScanline(3T)
NAME
TIFFWriteScanline - 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 (PlanarConfigura-
tion=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 compressed according to the compression scheme of the current TIFF
directory (see further below). If the current scanline is past the
end of the current subfile, the ImageLength field is automatically
increased to include the scanline (except for PlanarConfiguration=2,
where the ImageLength cannot be changed once the first data are writ-
ten). If the ImageLength is increased, the StripOffsets and Strip-
ByteCounts 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 TIFFSetField(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 VALUES
TIFFWriteScanline returns -1 if it immediately detects an error and 1
for a successful write.
DIAGNOSTICS
All error messages are directed to the TIFFError(3T) routine.
%s: File not open for writing . The file was opened for reading, not
writing.
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 orga-
nized in tiles because the TileWidth and TileLength tags have been set
with TIFFSetField(3T).
Compression algorithm does not support random access. Data was writ-
ten in a non-sequential order to a file that uses a compression algo-
rithm 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 ran-
dom 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 informa-
tion on how to do this.
%s: Must set "PlanarConfiguration" before writing data. The organiza-
tion of data has not be defined before the first write. See TIFFSet-
Field(3T) for information on how to do this.
Can not change "ImageLength" when using separate planes. Separate
image planes are being used (PlanarConfiguration=2), but the number of
rows has not been specified before the first write. The library sup-
ports the dynamic growth of an image only when data are organized in a
contiguous 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 PlanarConfiguration=1 the library does not
pack the block-interleaved samples.
SEE ALSO
libtiff(3T), TIFFOpen(3T), TIFFWriteEncodedStrip(3T), TIFFWriteRaw-
Strip(3T)
December 16, 1991 TIFFWriteScanline(3T)
