#define TIFFGetR(abgr) ((abgr) & 0xff)
#define TIFFGetG(abgr) (((abgr) >> 8) & 0xff)
#define TIFFGetB(abgr) (((abgr) >> 16) & 0xff)
#define TIFFGetA(abgr) (((abgr) >> 24) & 0xff)
int TIFFReadRGBATile(TIFF *tif, uint32 x, uint32 y, uint32 *raster)
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 width times length 32-bit entries,
where width is the width of a tile (TIFFTAG_TILEWIDTH) and length is the
height of a tile (TIFFTAG_TILELENGTH).
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
TIFFGetA should be used to access individual samples. Images without Associated Alpha
matting information have a constant Alpha of 1.0 (255).
page for more details on how various image types are converted to RGBA values.
Samples must be either 1, 2, 4, 8, or 16 bits. Colorimetric samples/pixel must
be either 1, 3, or 4 (i.e.
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
facilities. Its main advantage over the similar
TIFFReadRGBAImage() function is that for large images a single buffer capable of holding the whole
image doesnt need to be allocated, only enough for one tile. The
TIFFReadRGBAStrip() function does a similar operation for stripped images.
All error messages are directed to the
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
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
Missing required "Colormap" tag.
A Palette image did not have a required
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
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
No space for Palette mapping table. There was insufficient memory to allocate a table used to map data to 8-bit