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TIFFReadRGBAStrip(3TIFF)			      TIFFReadRGBAStrip(3TIFF)

NAME
       TIFFReadRGBAStrip  - read and decode an image strip into	a fixed-format
       raster

SYNOPSIS
       #include	<tiffio.h>

       #define TIFFGetR(abgr) ((abgr) &	0xff)
       #define TIFFGetG(abgr) (((abgr) >> 8) & 0xff)
       #define TIFFGetB(abgr) (((abgr) >> 16) &	0xff)
       #define TIFFGetA(abgr) (((abgr) >> 24) &	0xff)

       int TIFFReadRGBAStrip(TIFF *tif,	uint32 row, uint32 *raster)

DESCRIPTION
       TIFFReadRGBAStrip reads a single	strip of a strip-based image into mem-
       ory,  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 rowsper-
       strip 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 organiza-
       tion.  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 ac-
       cess individual samples.	Images without Associated Alpha	matting	infor-
       mation 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.

NOTES
       Samples	must  be  either  1,  2,  4,  8, or 16 bits. Colorimetric sam-
       ples/pixel must be either 1, 3, or 4 (i.e.  SamplesPerPixel  minus  Ex-
       traSamples).

       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 TIFFRGBAIm-
       age(3TIFF)  facilities.	It's main advantage over the similar TIFFRead-
       RGBAImage() function is that for	large images a single  buffer  capable
       of  holding  the	 whole image doesn't need to be	allocated, only	enough
       for one strip.  The TIFFReadRGBATile() function does a  similar	opera-
       tion for	tiled images.

RETURN VALUES
       1 is returned if	the image was successfully read	and converted.	Other-
       wise, 0 is returned if an error was encountered.

DIAGNOSTICS
       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 "PhotometricInterpretation" tag.	The image did not have
       a tag that describes how	to display the data.

       No  "PhotometricInterpretation" tag, assuming RGB.  The image was miss-
       ing a tag that describes	how to display it, but because it has 3	 or  4
       samples/pixel, it is assumed to be RGB.

       No  "PhotometricInterpretation"	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 mem-
       ory for a table used to convert image samples to	8-bit RGB.

       Missing required	"Colormap" tag.	 A Palette image did not  have	a  re-
       quired 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 BitsPer-
       Sample, SamplesPerPixel,	and PhotometricInterpretation) that  TIFFRead-
       RGBAImage can not handle.

       No space	for B&W	mapping	table.	There was insufficient memory to allo-
       cate 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.

SEE ALSO
       TIFFOpen(3TIFF),	 TIFFRGBAImage(3TIFF), TIFFReadRGBAImage(3TIFF), TIFF-
       ReadRGBATile(3TIFF), libtiff(3TIFF)

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

libtiff			       December	10, 1998      TIFFReadRGBAStrip(3TIFF)

NAME | SYNOPSIS | DESCRIPTION | NOTES | RETURN VALUES | DIAGNOSTICS | SEE ALSO

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