.\" $Id: TIFFReadRGBAImage.3tiff,v 1.4 2006/10/13 07:22:01 dron Exp $

.\"

.\" Copyright (c) 1991-1997 Sam Leffler

.\" Copyright (c) 1991-1997 Silicon Graphics, Inc.

.\"

.\" Permission to use, copy, modify, distribute, and sell this software and 

.\" its documentation for any purpose is hereby granted without fee, provided

.\" that (i) the above copyright notices and this permission notice appear in

.\" all copies of the software and related documentation, and (ii) the names of

.\" Sam Leffler and Silicon Graphics may not be used in any advertising or

.\" publicity relating to the software without the specific, prior written

.\" permission of Sam Leffler and Silicon Graphics.

.\" 

.\" THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND, 

.\" EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY 

.\" WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.  

.\" 

.\" IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR

.\" ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,

.\" OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,

.\" WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF 

.\" LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE 

.\" OF THIS SOFTWARE.

.\"

.if n .po 0

.TH TIFFReadRGBAImage 3TIFF "October 13, 2006" "libtiff"

.SH NAME

TIFFReadRGBAImage, TIFFReadRGBAImageOriented \- read and decode an image

into a fixed-format raster

.SH SYNOPSIS

.B "#include <tiffio.h>"

.sp

.B "#define TIFFGetR(abgr) ((abgr) & 0xff)"

.br

.B "#define TIFFGetG(abgr) (((abgr) >> 8) & 0xff)"

.br

.B "#define TIFFGetB(abgr) (((abgr) >> 16) & 0xff)"

.br

.B "#define TIFFGetA(abgr) (((abgr) >> 24) & 0xff)"

.sp

.BI "int TIFFReadRGBAImage(TIFF *" tif ", uint32 " width ", uint32 " height ", uint32 *" raster ", int " stopOnError ")"

.br

.BI "int TIFFReadRGBAImageOriented(TIFF *" tif ", uint32 " width ", uint32 " height ", uint32 *" raster ", int " orientation ", int " stopOnError ")"

.br

.SH DESCRIPTION

.IR TIFFReadRGBAImage

reads a strip- or tile-based image into memory, storing the

result in the user supplied

.IR raster .

The raster is assumed to be an array of

.I width

times

.I height

32-bit entries, where

.I width

must be less than or equal to the width of the image (\c

.I 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 (\fIx\fP,\fIy\fP) is \fIraster\fP[\fIy\fP*\fIwidth\fP+\fIx\fP];

with the raster origin in the lower-left hand corner.)

.PP

.IR TIFFReadRGBAImageOriented

works like

.IR TIFFReadRGBAImage

with except of that user can specify the raster origin position with the

.I orientation

parameter. Four orientations supported:

.TP

.B ORIENTATION_TOPLEFT

origin in top-left corner,

.TP

.B ORIENTATION_TOPRIGHT

origin in top-right corner,

.TP

.B ORIENTATION_BOTLEFT

origin in bottom-left corner

and

.TP

.B ORIENTATION_BOTRIGHT

origin in bottom-right corner.

.LP

If you choose

.B ORIENTATION_BOTLEFT

result will be the same as returned by the

.IR TIFFReadRGBAImage.

.PP

Raster pixels are 8-bit packed red, green, blue, alpha samples.

The macros

.IR TIFFGetR ,

.IR TIFFGetG ,

.IR TIFFGetB ,

and

.I TIFFGetA

should be used to access individual samples.

Images without Associated Alpha matting information have a constant

Alpha of 1.0 (255).

.PP

.I TIFFReadRGBAImage

converts non-8-bit images by scaling sample values.

Palette, grayscale, bilevel, 

.SM CMYK\c

, and YCbCr images are converted to

.SM RGB

transparently.

Raster pixels are returned uncorrected by any colorimetry information

present in the directory.

.PP

The paramater

.I stopOnError

specifies how to act if an error is encountered while reading

the image.

If

.I stopOnError

is non-zero, then an error will terminate the operation; otherwise

.I TIFFReadRGBAImage

will continue processing data until all the possible data in the

image have been requested.

.SH NOTES

In C++ the

.I stopOnError

parameter defaults to 0.

.PP

Samples must be either 1, 2, 4, 8, or 16 bits.

Colorimetric samples/pixel must be either 1, 3, or 4 (i.e.

.I SamplesPerPixel

minus

.IR ExtraSamples ).

.PP

Palettte image colormaps that appear to be incorrectly written

as 8-bit values are automatically scaled to 16-bits.

.PP

.I TIFFReadRGBAImage

is just a wrapper around the more general

.IR TIFFRGBAImage (3TIFF)

facilities.

.SH "RETURN VALUES"

1 is returned if the image was successfully read and converted.

Otherwise, 0 is returned if an error was encountered and

.I stopOnError

is zero.

.SH DIAGNOSTICS

All error messages are directed to the

.IR TIFFError (3TIFF)

routine.

.PP

.BR "Sorry, can not handle %d-bit pictures" .

The image had

.I BitsPerSample

other than 1, 2, 4, 8, or 16.

.PP

.BR "Sorry, can not handle %d-channel images" .

The image had

.I SamplesPerPixel

other than 1, 3, or 4.

.PP

\fBMissing needed "PhotometricInterpretation" tag\fP.

The image did not have a tag that describes how to display

the data.

.PP

\fBNo "PhotometricInterpretation" tag, assuming RGB\fP.

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

.SM RGB.

.PP

\fBNo "PhotometricInterpretation" tag, assuming min-is-black\fP.

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.

.PP

.BR "No space for photometric conversion table" .

There was insufficient memory for a table used to convert

image samples to 8-bit

.SM RGB.

.PP

\fBMissing required "Colormap" tag\fP.

A Palette image did not have a required

.I Colormap

tag.

.PP

.BR "No space for tile buffer" .

There was insufficient memory to allocate an i/o buffer.

.PP

.BR "No space for strip buffer" .

There was insufficient memory to allocate an i/o buffer.

.PP

.BR "Can not handle format" .

The image has a format (combination of

.IR BitsPerSample ,

.IR SamplesPerPixel ,

and

.IR PhotometricInterpretation )

that

.I TIFFReadRGBAImage

can not handle.

.PP

.BR "No space for B&W mapping table" .

There was insufficient memory to allocate a table used to map

grayscale data to

.SM RGB.

.PP

.BR "No space for Palette mapping table" .

There was insufficient memory to allocate a table used to map

data to 8-bit

.SM RGB.

.SH "SEE ALSO"

.BR TIFFOpen (3TIFF),

.BR TIFFRGBAImage (3TIFF),

.BR TIFFReadRGBAStrip (3TIFF),

.BR TIFFReadRGBATile (3TIFF),

.BR libtiff (3TIFF)

.PP

Libtiff library home page:

.BR http://www.remotesensing.org/libtiff/