TIFFReadDirectory(3TIFF)                 TIFFReadDirectory(3TIFF)



NAME
       TIFFReadDirectory - get the contents of the next directory
       in an open TIFF file

SYNOPSIS
       #include 

       int TIFFReadDirectory(TIFF *tif)

DESCRIPTION
       Read the next directory in the specified file and make  it
       the  current  directory.  Applications  only  need to call
       TIFFReadDirectory to read multiple subfiles  in  a  single
       TIFF file-- the first directory in a file is automatically
       read when TIFFOpen is called.

NOTES
       If the library is compiled with STRIPCHOP_SUPPORT enabled,
       then  images that have a single uncompressed strip or tile
       of data are automatically treated as if they were made  up
       of  multiple  strips or tiles of approximately 8 kilobytes
       each. This operation is done only in-memory; it  does  not
       alter  the contents of the file. However, the construction
       of the ``chopped strips'' is visible  to  the  application
       through  the number of strips [tiles] returned by TIFFNum-
       berOfStrips [TIFFNumberOfTiles].

RETURN VALUES
       If  the  next  directory  was  successfully  read,  1   is
       returned. Otherwise, 0 is returned if an error was encoun-
       tered, or if there are no more directories to be read.

DIAGNOSTICS
       All error messages are directed  to  the  TIFFError(3TIFF)
       routine.    All  warning  messages  are  directed  to  the
       TIFFWarning(3TIFF) routine.

       Seek error accessing TIFF directory.   An  error  occurred
       while positioning to the location of the directory.

       Wrong  data  type %d for field "%s".  The tag entry in the
       directory had an incorrect data  type.   For  example,  an
       ImageDescription tag with a SHORT data type.

       TIFF directory is missing required "%s" field.  The speci-
       fied tag is required to be present by the TIFF 5.0  speci-
       fication,  but  is  missing.   The  directory is (usually)
       unusable.

       %s: Rational with zero denominator.  A directory tag has a
       RATIONAL value whose denominator is zero.

       Incorrect  count  %d  for field "%s" (%lu, expecting %lu);
       tag ignored.  The specified tag's count field is bad.  For
       example, a count other than 1 for a SubFileType tag.

       Cannot  handle different per-sample values for field "%s".
       The tag has SamplesPerPixel values and they  are  not  all
       the  same;  e.g.  BitsPerSample.  The library is unable to
       handle images of this sort.

       Count mismatch for field "%s"; expecting %d, got %d.   The
       count  field  in  a  tag  does  not  agree with the number
       expected by the library.  This should never happen, so  if
       it does, the library refuses to read the directory.

       Invalid  TIFF  directory; tags are not sorted in ascending
       order.  The directory tags  are  not  properly  sorted  as
       specified  in  the  TIFF 5.0 specification.  This error is
       not fatal.

       Ignoring unknown field with tag %d (0x%x).  An unknown tag
       was  encountered in the directory; the library ignores all
       such tags.

       TIFF directory is  missing  requred  "ImageLength"  field.
       The  image violates the specification by not having a nec-
       essary field.  There is no way for the library to  recover
       from this error.

       TIFF  directory  is  missing requred "PlanarConfig" field.
       The image violates the specification by not having a  nec-
       essary  field.  There is no way for the library to recover
       from this error.

       TIFF directory is missing  requred  "StripOffsets"  field.
       The image has multiple strips, but is missing the tag that
       specifies the file offset to each strip of data.  There is
       no way for the library to recover from this error.

       TIFF  directory  is  missing  requred "TileOffsets" field.
       The image has multiple tiles, but is missing the tag  that
       specifies  the file offset to each tile of data.  There is
       no way for the library to recover from this error.

       TIFF  directory  is  missing  required   "StripByteCounts"
       field.   The image has multiple strips, but is missing the
       tag that specifies the size of each strip of data.   There
       is no way for the library to recover from this error.

       TIFF   directory  is  missing  required  "StripByteCounts"
       field, calculating from imagelength.  The  image  violates
       the  specification  by not having a necessary field.  How-
       ever, when the image is comprised of  only  one  strip  or
       tile, the library will estimate the missing value based on
       the file size.

       Bogus "StripByteCounts" field,  ignoring  and  calculating
       from  imagelength.  Certain vendors violate the specifica-
       tion by writing zero for the StripByteCounts tag when they
       want  to  leave the value unspecified.  If the image has a
       single strip, the library will estimate the missing  value
       based on the file size.

SEE ALSO
       libtiff(3TIFF),      TIFFOpen(3TIFF),      TIFFWriteDirec-
       tory(3TIFF),   TIFFSetDirectory(3TIFF),   TIFFSetSubDirec-
       tory(3TIFF)



libtiff                  October 15, 1995TIFFReadDirectory(3TIFF)