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Edit File: TIFFReadRGBAImage.3tiff.html

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<h1 align=center>TIFFReadRGBAImage</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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TIFFReadRGBAImage, TIFFReadRGBAImageOriented &minus; read
and decode an image 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 TIFFReadRGBAImage(TIFF *tif,
uint32 width, uint32 height,
uint32 *raster, int
stopOnError) 
int TIFFReadRGBAImageOriented(TIFF *tif,
uint32 width, uint32 height,
uint32 *raster, int orientation,
int stopOnError)
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<a name="DESCRIPTION"></a>
<h2>DESCRIPTION</h2>

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TIFFReadRGBAImage reads a strip- or tile-based
image into memory, storing the result in the user supplied
raster. The raster is assumed to be an array of
width times height 32-bit entries, where
width must be less than or equal to the width of the
image (height may be any non-zero size). If the
raster dimensions are smaller than the image, the image data
is cropped to the raster bounds. If the raster height is
greater than that of the image, then the image data are
placed in the lower part of the raster. (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.)

TIFFReadRGBAImageOriented works like
TIFFReadRGBAImage with except of that user can
specify the raster origin position with the
orientation parameter. Four orientations
supported:
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ORIENTATION_TOPLEFT</td>
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origin in top-left corner,
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ORIENTATION_TOPRIGHT</td>
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origin in top-right corner,
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ORIENTATION_BOTLEFT</td>
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origin in bottom-left corner and
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ORIENTATION_BOTRIGHT</td>
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origin in bottom-right corner.
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If you choose ORIENTATION_BOTLEFT result will be
the same as returned by the TIFFReadRGBAImage.

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).

TIFFReadRGBAImage converts non-8-bit images by
scaling sample values. Palette, grayscale, bilevel,
CMYK , and YCbCr images are converted to
RGB transparently. Raster pixels are returned
uncorrected by any colorimetry information present in the
directory.

The paramater stopOnError specifies how to act if
an error is encountered while reading the image. If
stopOnError is non-zero, then an error will terminate
the operation; otherwise TIFFReadRGBAImage will
continue processing data until all the possible data in the
image have been requested.
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<a name="NOTES"></a>
<h2>NOTES</h2>

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In C++ the stopOnError parameter defaults to
0.

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).

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

TIFFReadRGBAImage is just a wrapper around the
more general TIFFRGBAImage(3TIFF) facilities.
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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 and stopOnError is zero.
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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),
TIFFReadRGBAStrip(3TIFF),
TIFFReadRGBATile(3TIFF), libtiff(3TIFF)

Libtiff library home page:
http://www.remotesensing.org/libtiff/
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