bionic (3) TIFFReadRGBAImage.3tiff.gz

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, uint32 width, uint32 height, uint32 *raster, int stopOnError)
       int  TIFFReadRGBAImageOriented(TIFF  *tif,  uint32 width, uint32 height, uint32 *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 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  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 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 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  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;  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.

       Samples  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.

       TIFFReadRGBAImage is just a wrapper around the more general TIFFRGBAImage(3TIFF) 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 TIFFError(3TIFF) 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)

       Libtiff library home page: http://www.simplesystems.org/libtiff/