NAME

       TIFFReadRGBATile - read and decode an image tile into a fixed-format raster

SYNOPSIS

          #include <tiffio.h>

       int TIFFReadRGBATile(TIFF *tif, uint32_t x, uint32_t y, uint32_t *raster)

       int  TIFFReadRGBATileExt(TIFF  *tif,  uint32_t  col,  uint32_t  row, uint32_t *raster, int
       stop_on_error)

DESCRIPTION

       TIFFReadRGBATile() reads a single tile of a tile-based  image  into  memory,  storing  the
       result  in  the  user  supplied  RGBA  raster.   The  raster  is assumed to be an array of
       TileWidth  ×  TileLength  32-bit  entries,  where  TileWidth  is  the  width  of  a   tile
       (TIFFTAG_TILEWIDTH) and TileLength is the height of a tile (TIFFTAG_TILELENGTH).

       TIFFReadRGBATileExt() provides the parameter stop_on_error.  Its behaviour is described at
       TIFFReadRGBAImage.

       The x and y values are the offsets from the top left corner to the top left corner of  the
       tile to be read.  They must be an exact multiple of the tile width and length.

       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
       tile. That is bottom to top organization.  Edge tiles which partly fall off the image will
       be filled out with appropriate zeroed areas.

       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 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 samples/pixel must be either
       1, 3, or 4 (i.e.  SamplesPerPixel - ExtraSamples).

       Palette image colormaps that  appear  to  be  incorrectly  written  as  8-bit  values  are
       automatically scaled to 16-bits.

       TIFFReadRGBATile()  is  just  a  wrapper around the more general TIFFRGBAImage facilities.
       It's main advantage over the similar TIFFReadRGBAImage() 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 tile.  The  TIFFReadRGBAStrip()  function  does  a  similar  operation  for
       stripped images.

RETURN VALUES

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

DIAGNOSTICS

       All error messages are directed to the TIFFErrorExtR() 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),  TIFFReadRGBAImage  (3tiff), TIFFReadRGBAStrip
       (3tiff), libtiff (3tiff)

AUTHOR

       LibTIFF contributors

COPYRIGHT

       1988-2023, LibTIFF contributors