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TIFFWriteScanline

NAME

SYNOPSIS

DESCRIPTION

NOTES

RETURN VALUES

DIAGNOSTICS

BUGS

SEE ALSO

NAME

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TIFFWriteScanline − write a scanline to an open

<small>TIFF</small> file

SYNOPSIS

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#include <tiffio.h>

int TIFFWriteScanline(TIFF *tif,

tdata_t buf, uint32 row,

tsample_t sample)

DESCRIPTION

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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 <small>TIFF</small> 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

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The library writes encoded data using the native machine

byte order. Correctly implemented <small>TIFF</small>

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

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TIFFWriteScanline returns −1 if it

immediately detects an error and 1 for a successful

write.

DIAGNOSTICS

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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

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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

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TIFFOpen(3TIFF),

TIFFWriteEncodedStrip(3TIFF),

TIFFWriteRawStrip(3TIFF), libtiff(3TIFF)

Libtiff library home page:

http://www.remotesensing.org/libtiff/