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
       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.

NOTES
       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's main advantage over the similar
       TIFFReadRGBAImage() 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
       operation for tiled images.

RETURN VALUES
       1 is returned if the image was successfully read and converted.
       Otherwise, 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
       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 "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
       memory for a table used to convert image samples to 8-bit RGB.

       Missing required "Colormap" 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&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.

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

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




libtiff                        December 10, 1998      TIFFReadRGBAStrip(3TIFF)
