TIFFReadRGBAImage(3TIFF)                              TIFFReadRGBAImage(3TIFF)



NAME
       TIFFReadRGBAImage, TIFFReadRGBAImageOriented - read and decode an image
       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 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)

DESCRIPTION
       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:

       ORIENTATION_TOPLEFT
              origin in top-left corner,

       ORIENTATION_TOPRIGHT
              origin in top-right corner,

       ORIENTATION_BOTLEFT
              origin in bottom-left corner and

       ORIENTATION_BOTRIGHT
              origin in bottom-right corner.

       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.

NOTES
       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.

RETURN VALUES
       1 is returned if the image was successfully read and converted.
       Otherwise, 0 is returned if an error was encountered and stopOnError is
       zero.

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), TIFFReadRGBAStrip(3TIFF),
       TIFFReadRGBATile(3TIFF), libtiff(3TIFF)

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



libtiff                        October 13, 2006       TIFFReadRGBAImage(3TIFF)
