NAME

 
FitsIO - C++ Class for Reading, Writing and Managing FITS Images

SYNOPSIS

 
#include "FitsIO.h"

class FitsIO : public ImageIORep {
...
public:
    FitsIO(int width, int height, int bitpix, double bzero,
           double bscale, const Mem& header, const Mem& data);

    ~FitsIO() {}

    int wcsinit();

    int nativeByteOrder() const;
    const char* classname() const;

    static FitsIO* read(const char* filename, int memOptions = 0);
    int write(const char *filename) const;

    static FitsIO* initialize(Mem& header);
    static FitsIO* initialize(Mem& header, Mem& data);

    static FitsIO* blankImage(double ra, double dec, double equinox,
                              double radius, int width, int height,
                              unsigned long color0);

    int get(const char* keyword, double& val) const;
    int get(const char* keyword, float& val) const;
    int get(const char* keyword, int& val) const;
    char* get(const char* keyword) const;

    static int get(const Mem& header, const char* keyword, double& val);
    static int get(const Mem& header, const char* keyword, float& val);
    static int get(const Mem& header, const char* keyword, int& val);
    static char* get(const Mem& header, const char* keyword);

    int getFitsHeader(ostream& os) const;

    int put(const char* keyword, double val, const char* comment);
    int put(const char* keyword, float val, const char* comment);
    int put(const char* keyword, int val, const char* comment);
    int put(const char* keyword, const char* val, const char* comment);
};

DESCRIPTION

 
This class handles the reading and writing of FITS images and access
to the FITS header and keywords. It is based in part on the saoimage
routines in the wcslib directory. Currently the reading and writing is
implemented in this class, but that may be replaced by a standard FITS
I/O package in the future.

This class is a subclass of ImageIORep, which is the internal class
used by class ImageIO for reference counting. The public interface is
generally through the ImageIO class, although class FitsIO may be used
directly in cases where you know that the image is already in FITS
format or you are creating a new image in FITS format.

Besides reading and writing FITS images, this class can be used to
create a FITS image from data in memory and to create a "blank" image
with World Coordinate information for plotting astronomical objects.

CREATING A FITSIO OBJECT

 
To create a FitsIO object from a FITS file, use the read method, which
returns a pointer to an allocated FitsIO object given the file name.
If you have the image data in memory, you can use one of the
constructors to create the object.

You can pass a pointer to a FitsIO object to the ImageIO constructor
to create a reference counted ImageIO object, for example:

        ImageIO imio = FitsIO::read(filename);
or
        ImageIO imio = new FitsIO(w, h, type, bzero, bscale, header, data);

COMPRESSION

 
Images are compressed and decompressed automatically by the read and
write methods based on the file name suffix: ".hfits" for H-compress,
".gzfits" or ".gfits" for gzip compression, and ".cfits" for UNIX
compression. See Compress for details.

METHODS

 
FitsIO(width, height, bitpix, bzero, bscale, header,  data)
        This constructor is called by the static "read" method once
        the FITS file has been read. The parameters are based on
        values read from the FITS header. The header and data
        arguments are instances of class Mem, which uses reference
        counting to manage shared and unshared memory.

read(filename, int memOptions = 0)
        Read a FITS file and return an initialized FitsIO object for
        it, or NULL if there are errors.  If filename is "-", stdin is
        read into a temp image file and used as the input.  The Mem
        class is used to speed up loading the file. The optional
        mem_options argument controls whether the memory is mapped
        read-only or read/write. See class Mem for the available
        options.

write(filename)
        Write the data to a FITS file.

blankImage(ra, dec, equinox, radius, width, height, color0)
        Generate a blank image with a FITS header based on the given
        fields and including support for World Coordinates. RA and DEC
        are specified in degrees. Width and Height are in
        pixels. "color0" is the value to use for the image pixels
        (usually the value for "black").

get(keyword, val)
        Find and set the value for the given FITS keyword and return 0
        if OK (found). This method is overloaded for various data types.

get(keyword)
        Find and return the string value for the given FITS keyword,
        or NULL if not found.

getFitsHeader(os)
        Write an ASCII formatted copy of the FITS header to the given
        stream, format it in 80 char lines and replace any NULL chars
        with blanks.

put(keyword, val, comment)
        Insert the given FITS keyword and value with the given comment
        in the FITS header and return 0 if all is OK. If there is not
        enough space in the FITS header, extend the size of the FITS
        header by one header block and if the header is part of an
        mmap'ed file, rewrite the file with the new enlarged
        header. This creates a temp file in the same dir as the file
        called <file>.tmp.

SEE ALSO

 
ImageIO(3++), ImageData, Mem(3C++), Compress(3C++)

 


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Last change: 08 Sep 98