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✏️ Editing: TIFFReadRGBAStrip.3tiff.html

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<h1 align=center>TIFFReadRGBAStrip</h1>
<a href="#NAME">NAME</a> 
<a href="#SYNOPSIS">SYNOPSIS</a> 
<a href="#DESCRIPTION">DESCRIPTION</a> 
<a href="#NOTES">NOTES</a> 
<a href="#RETURN VALUES">RETURN VALUES</a> 
<a href="#DIAGNOSTICS">DIAGNOSTICS</a> 
<a href="#SEE ALSO">SEE ALSO</a>

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<a name="NAME"></a>
<h2>NAME</h2>

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TIFFReadRGBAStrip &minus; read and decode an image strip
into a fixed-format raster
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<a name="SYNOPSIS"></a>
<h2>SYNOPSIS</h2>

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#include &lt;tiffio.h&gt;

#define TIFFGetR(abgr) ((abgr) &amp; 0xff) 
#define TIFFGetG(abgr) (((abgr) &gt;&gt; 8) &amp; 0xff) 
#define TIFFGetB(abgr) (((abgr) &gt;&gt; 16) &amp; 0xff) 
#define TIFFGetA(abgr) (((abgr) &gt;&gt; 24) &amp;
0xff)

int TIFFReadRGBAStrip(TIFF *tif,
uint32 row, uint32
*raster)
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<a name="DESCRIPTION"></a>
<h2>DESCRIPTION</h2>

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TIFFReadRGBAStrip reads a single strip of a
strip-based image into memory, storing the result in the
user supplied RGBA raster. The raster is assumed to
be an array of width times rowsperstrip 32-bit entries,
where width is the width of the image (TIFFTAG_IMAGEWIDTH)
and rowsperstrip is the maximum lines in a strip
(TIFFTAG_ROWSPERSTRIP).

The row value should be the row of the first row
in the strip (strip * rowsperstrip, zero based).

Note that the raster is assume to be organized such that
the pixel at location (x,y) is
raster[y*width+x]; with the
raster origin in the lower-left hand corner of the
strip. That is bottom to top organization. When reading a
partial last strip in the file the last line of the image
will begin at the beginning of the buffer.

Raster pixels are 8-bit packed red, green, blue, alpha
samples. The macros TIFFGetR, TIFFGetG,
TIFFGetB, and TIFFGetA should be used to
access individual samples. Images without Associated Alpha
matting information have a constant Alpha of 1.0 (255).

See the TIFFRGBAImage(3TIFF) page for more details
on how various image types are converted to RGBA values.
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<a name="NOTES"></a>
<h2>NOTES</h2>

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Samples must be either 1, 2, 4, 8, or 16 bits.
Colorimetric samples/pixel must be either 1, 3, or 4 (i.e.
SamplesPerPixel minus ExtraSamples).

Palette image colormaps that appear to be incorrectly
written as 8-bit values are automatically scaled to
16-bits.

TIFFReadRGBAStrip is just a wrapper around the
more general TIFFRGBAImage(3TIFF) facilities.
It&rsquo;s main advantage over the similar
TIFFReadRGBAImage() function is that for large images
a single buffer capable of holding the whole image
doesn&rsquo;t need to be allocated, only enough for one
strip. The TIFFReadRGBATile() function does a similar
operation for tiled images.
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<a name="RETURN VALUES"></a>
<h2>RETURN VALUES</h2>

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1 is returned if the image was successfully read and
converted. Otherwise, 0 is returned if an error was
encountered.
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<a name="DIAGNOSTICS"></a>
<h2>DIAGNOSTICS</h2>

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All error messages are directed to the
TIFFError(3TIFF) routine.

Sorry, can not handle %d-bit pictures. The image
had BitsPerSample other than 1, 2, 4, 8, or 16.

Sorry, can not handle %d-channel images. The image
had SamplesPerPixel other than 1, 3, or 4.

Missing needed &quot;PhotometricInterpretation&quot;
tag. The image did not have a tag that describes how to
display the data.

No &quot;PhotometricInterpretation&quot; tag, assuming
RGB. The image was missing a tag that describes how to
display it, but because it has 3 or 4 samples/pixel, it is
assumed to be RGB.

No &quot;PhotometricInterpretation&quot; tag, assuming
min-is-black. The image was missing a tag that describes
how to display it, but because it has 1 sample/pixel, it is
assumed to be a grayscale or bilevel image.

No space for photometric conversion table. There
was insufficient memory for a table used to convert image
samples to 8-bit RGB.

Missing required &quot;Colormap&quot; tag. A
Palette image did not have a required Colormap
tag.

No space for tile buffer. There was insufficient
memory to allocate an i/o buffer.

No space for strip buffer. There was insufficient
memory to allocate an i/o buffer.

Can not handle format. The image has a format
(combination of BitsPerSample,
SamplesPerPixel, and
PhotometricInterpretation) that
TIFFReadRGBAImage can not handle.

No space for B&amp;W mapping table. There was
insufficient memory to allocate a table used to map
grayscale data to RGB.

No space for Palette mapping table. There was
insufficient memory to allocate a table used to map data to
8-bit RGB.
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<a name="SEE ALSO"></a>
<h2>SEE ALSO</h2>

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TIFFOpen(3TIFF), TIFFRGBAImage(3TIFF),
TIFFReadRGBAImage(3TIFF),
TIFFReadRGBATile(3TIFF), libtiff(3TIFF)

Libtiff library home page:
http://www.simplesystems.org/libtiff/
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MR SKB