TIFFREADRGBAIMAGE(3tiff) LibTIFF TIFFREADRGBAIMAGE(3tiff)
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)
TIFFReadRGBAImage(3) *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 x 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 x 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:
o ORIENTATION_TOPLEFT: origin in top-left corner,
o ORIENTATION_TOPRIGHT: origin in top-right corner,
o ORIENTATION_BOTLEFT: origin in bottom-left corner
o 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(3), TIFFRGBAImage(3), TIFFReadRGBAStrip(3),
TIFFReadRGBATile(3), libtiff(3)
AUTHOR
LibTIFF contributors
COPYRIGHT
1988-2022, LibTIFF contributors
4.6 October 9, 2023 TIFFREADRGBAIMAGE(3tiff)
tiff 4.6.0 - Generated Tue Oct 10 14:04:37 CDT 2023