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
       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 sam-
       ples/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 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
       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 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.remotesensing.org/libtiff/

libtiff                        December 10, 1998      TIFFReadRGBAStrip(3TIFF)