Reading an Image

Image reading calls are made very simple: the FITS object is created with the readDataFlag set to true, and reading is done on construction. The following call

image.read(contents) 

calls

PHDU::read(std::valarray<S>& image).

This copies the entire image from the FITS object into the std::valarray object contents, sizing it as necessary. PHDU::read() and ExtHDU::read() [for image extensions] take a range of arguments that support (a) reading the entire image - as in this example; (b) sections of an image starting from a given pixel; (c) rectangular subsets. See the class references for PHDU and ExtHDU for details.

int readImage()
{
    std::auto_ptr<FITS> pInfile(new FITS("atestfil.fit",Read,true));

    PHDU& image = pInfile->pHDU(); 

    std::valarray<unsigned long>  contents;

    // read all user-specifed, coordinate, and checksum keys in the image
    image.readAllKeys();

    image.read(contents);

    // this doesn't print the data, just header info.
    std::cout << image << std::endl;

    long ax1(image.axis(0));
    long ax2(image.axis(1));

    for (long j = 0; j < ax2; j+=10)
    {
          std::ostream_iterator<short> c(std::cout,"\t");
          std::copy(&contents[j*ax1],&contents[(j+1)*ax1-1],c);
          std::cout << '\n';       
    }
 
    std::cout << std::endl;
    return 0;   
}