Tribblix: manual page: TIFFWriteScanline.3tiff

TIFFWriteScanline(3TIFF) TIFFWriteScanline(3TIFF)

NAME

TIFFWriteScanline - write a scanline to an open TIFF file

SYNOPSIS

#include <tiffio.h>

int TIFFWriteScanline(TIFF *tif, tdata_t buf, uint32_t 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 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 written). If the ImageLength is increased, the
StripOffsets 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 TIFFSetField(3TIFF) 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(3TIFF) 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
organized in tiles because the TileWidth and TileLength tags have
been set with TIFFSetField(3TIFF).

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(3TIFF) 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(3TIFF) 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
supports 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.