Ubuntu Manpage: TIFFReadRGBAImage, TIFFReadRGBAImageOriented - read and decode an image into a fixed-

Provided by: libtiff5-dev_4.0.9-5ubuntu0.10_amd64

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.