TIFFReadRGBAImage(3TIFF)                 TIFFReadRGBAImage(3TIFF)



NAME
       TIFFReadRGBAImage,  TIFFReadRGBAImageOriented  -  read and
       decode an image into a fixed-format raster

SYNOPSIS
       #include 

       #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,  u_long  width,  u_long
       height, u_long *raster, int stopOnError)
       int  TIFFReadRGBAImageOriented(TIFF  *tif,  u_long  width,
       u_long height, u_long *raster, int orientation,  int  sto-
       pOnError)

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; oth-
       erwise  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.  Colorimet-
       ric samples/pixel must be either 1, 3, or  4  (i.e.   Sam-
       plesPerPixel 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 gen-
       eral TIFFRGBAImage(3TIFF) facilities.

RETURN VALUES
       1 is returned if the image was successfully read and  con-
       verted.   Otherwise, 0 is returned if an error was encoun-
       tered 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 sam-
       ples 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  (combina-
       tion     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 insuffi-
       cient memory to allocate a table used to map data to 8-bit
       RGB.

SEE ALSO
       TIFFOpen(3TIFF),    TIFFRGBAImage(3TIFF),   TIFFReadRGBAS-
       trip(3TIFF), TIFFReadRGBATile(3TIFF), libtiff(3TIFF)

       Libtiff   library   home   page:    http://www.remotesens-
       ing.org/libtiff/



libtiff                  October 29, 2004TIFFReadRGBAImage(3TIFF)