[Lazarus] FITS export of bitmaps (flexible image transport system)

[Bernd]

Before I move on to the next project and forget this thing again I
want to donate a little FITS library to the community. Currently it
can only create FITS files and not read them but this should not be
too difficult to add. I did not have any priority for this use case, I
create images and need to export them as valid FITS.

http://pastebin.com/zbATCW3b

It might still contain a few bugs, its only 3 days old but it does
work and exported truecolor or grayscale bitmaps can be read by IRIS
and this is basically all I need. It can be used/extended to
contain/export any arbitrary data but currently only methods for
automatically converting an 8*3 TBitmap into a NAXIS=3 (color) or
NAXIS=2 (gray) with BITPIX=8  are implemented and working. I am too
lazy to open a sourceforge project now just for this little file but I
thought others might have some use for this library too, maybe
somebody else is interested to put some more work into it. This is the
only Pascal implementtion of FITS I am currently aware of.

Usage:

var
  Bitmap: TBitmap;
  Fits: TFitsObect;

begin
  ...
  Fits := TFitsObject.CreateFromBitmap(Bitmap);
  Fits.SaveToFile(FileName);
  Fits.Free;

or before saving do things like

  Fits.Primary.HeaderBlock.AddCard(TFitsHeaderCard('exposure', 200));
  Fits.Primary.HeaderBlock.AddCard(TFitsHeaderCard('gain', 5));
  Fits.Primary.HeaderBlock.AddCard(TFitsHeaderCard('foo', 'bar baz whatever'));
  Fits.SaveToFile(FileName);