TIFFReadRGBAImage(3t)

TIFFReadRGBAImage(3TIFFMISC. REFERENCE MANUAL PAGETIFFReadRGBAImage(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, u_long width, u_long height
     int  TIFFReadRGBAImageOriented(TIFF  *tif,   u_long   width,
     u_long height

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 ras-
     ter  is  assume to be organized such that the pixel at loca-
     tion (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  sam-
     ples.  The macros TIFFGetR, TIFFGetG, TIFFGetB, and TIFFGetA
     should be used to access individual samples.  Images without

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TIFFReadRGBAImage(3TIFFMISC. REFERENCE MANUAL PAGETIFFReadRGBAImage(3TIFF)

     Associated  Alpha  matting information have a constant Alpha
     of 1.0 (255).

     TIFFReadRGBAImage converts non-8-bit images by scaling  sam-
     ple  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; other-
     wise  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.  SamplesPer-
     Pixel minus ExtraSamples).

     Palettte image colormaps that appear to be incorrectly writ-
     ten 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  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) rou-
     tine.

     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 Sam-
     plesPerPixel 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.

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TIFFReadRGBAImage(3TIFFMISC. REFERENCE MANUAL PAGETIFFReadRGBAImage(3TIFF)

     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 insuf-
     ficient  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 PhotometricInterpre-
     tation) 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

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

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