NAME

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

SYNOPSIS

          #include <tiffio.h>

       TIFFGetR(abgr)
              ((abgr)&0xff)

       TIFFGetG(abgr)
              (((abgr) >> 8) & 0xff)

       TIFFGetB(abgr)
              (((abgr) >> 16) & 0xff)

       TIFFGetA(abgr)
              (((abgr) >> 24) & 0xff)

       int  TIFFReadRGBAImage(TIFF  *tif,  uint32_t width, uint32_t height, uint32_t *raster, int
       stopOnError)

       int  TIFFReadRGBAImageOriented(TIFF  *tif,  uint32_t  width,  uint32_t  height,   uint32_t
       *raster, int orientation, int stopOnError)

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 ×  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()  except  that  the  user  can
       specify  the  raster origin position with the orientation parameter. Four orientations are
       supported:

       • ORIENTATION_TOPLEFT: origin in top-left corner,

       • ORIENTATION_TOPRIGHT: origin in top-right corner,

       • ORIENTATION_BOTLEFT: origin in bottom-left corner

       • ORIENTATION_BOTRIGHT: origin in bottom-right corner.

       If you choose ORIENTATION_BOTLEFT, the  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  parameter  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;
       otherwise 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.

       SamplesPerPixel must be either 1, 2, 4, 8, or 16 bits.  Colorimetric samples/pixel must be
       either 1, 3, or 4 (i.e.  SamplesPerPixel minus ExtraSamples).

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

       IFFReadRGBAImage() is just a wrapper around the more general TIFFRGBAImage facilities.

RETURN VALUES

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

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),  TIFFReadRGBAStrip  (3tiff),  TIFFReadRGBATile
       (3tiff), libtiff (3tiff)

AUTHOR

       LibTIFF contributors

COPYRIGHT

       1988-2024, LibTIFF contributors