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

       1988-2024, LibTIFF contributors

4.5                                               Sep 05, 2024                           TIFFREADRGBATILE(3tiff)