DeLaFits is a native Delphi and Lazarus class library for operation with files in the FITS format:

• reading, editing and building the HDU (header and data units)
• high-level access to Standard Extensions
• data rendering of the IMAGE extension

How to use

Just add the library source directory to your project’s search path

Basic API is in DeLaFitsCommon and DeLaFitsClasses units

For details, see User's Manual

Code Sample

uses
  SysUtils, Classes, Graphics, DeLaFitsCommon, DeLaFitsClasses, DeLaFitsPicture;

var

  Stream: TFileStream;

  Container: TFitsContainer;
  Picture: TFitsPicture;
  Head: TFitsPictureHead;
  Data: TFitsPictureData;
  Frame: TFitsPictureFrame;

  IndexLine: Integer;
  IndexElems: Int64;
  X, CountElems: Integer;
  Elems: array of Double;
  Region: TRegion;
  Bitmap: TBitmap;

begin

  Stream    := nil;
  Container := nil;
  Bitmap    := nil;

  try

    // Open FITS file

    Stream := TFileStream.Create('demo-image.fits', fmOpenReadWrite);

    // Create FITS container

    Container := TFitsContainer.Create(Stream);

    // Cast HDU[0] as IMAGE extension

    Picture := Container.Reclass(0, TFitsPicture) as TFitsPicture;

    // Get Objects of IMAGE extension

    Head  := Picture.Head;
    Data  := Picture.Data;
    Frame := Picture.Frames[0];

    // Edit Header

    IndexLine := Head.IndexOf('DATE-OBS');
    if IndexLine < 0 then
    begin
      Head.AddDateTime('DATE-OBS', Now, 'Add datetime');
    end
    else
    begin
      Head.ValuesDateTime[IndexLine] := Now;
      Head.Notes[IndexLine] := 'Set datetime';
    end;

    // Edit Data

    IndexElems := Frame.IndexElems;
    CountElems := Frame.LocalWidth;
    SetLength(Elems, CountElems);
    Data.ReadElems(IndexElems, CountElems, TA64f(Elems));
    for X := 0 to CountElems - 1 do
      Elems[X] := Elems[X] + 1.0;
    Data.WriteElems(IndexElems, CountElems, TA64f(Elems));

    // Render

    Bitmap := TBitmap.Create;
    Region := ToRegion(0, 0, 300, 300);
    Frame.Tone.Contrast := 1.2;
    Frame.Geometry.Scale(2.0, 2.0, xy00).Rotate(45.0, xy00);
    Frame.RenderScene(Bitmap, Region);
    Bitmap.SaveToFile('demo-image.bmp');

  finally
    Stream.Free;
    Container.Free;
    Elems := nil;
    Bitmap.Free;
  end;

end.

Data

The data directory contains samples FITS files

Custom Demo Samples
demo-asctable.fits	Primary HDU without data block and ASCII-TABLE extension: 5 x 10 table
demo-image.fits	Single Image: 2-dimensional primary array 1400 x 1000 with BITPIX = 16
demo-simple.fits	Single Image: 1-dimensional primary array 1 x 100 with BITPIX = 8, data block contains a sequence from 0 to 99
Official Individual Samples
01-HST-WFPC-II.fits	WFPC II 800 x 800 x 4 primary array data cube containing the 4 CCD images, plus a table extension containing world coordinate parameters. This sample file has been trimmed to 200 x 200 x 4 pixels to save disk space
02-HST-WFPC-II.fits	WFPC II 1600 x 1600 primary array mosaic constructed from the 4 individual CCD chips. Image has been trimmed to 100 x 100 pixels to save disk space
03-HST-FOC.fits	FOC 1024 x 1024 primary array image, plus a table extension containing world coordinate parameters
04-HST-FOS.fits	FOS 2 x 2064 primary array spectrum containing the flux and wavelength arrays, plus a small table extension
05-HST-HRS.fits	HRS 2000 x 4 primary array spectrum, plus a small table extension
06-HST-NICMOS.fits	NICMOS null primary array plus 5 image extensions 270 x 263 containing the science, error, data quality, samples, and time images
07-HST-FGS.fits	FGS file with a 89688 x 7 2-dimensional primary array and 1 table extension. The primary array contains a time series of 7 astrometric quantities
08-ASTRO-UIT.fits	Astro1 Ultraviolet Imaging Telescope 512 x 512 primary array image
09-IUE-LWP.fits	IUE spectrum contained in vector columns of a binary table
10-EUVE.fits	EUVE sky image and 2D spectra, contained in multiple image extensions, with associated binary table extensions
11-RANDOM-GROUPS.fits	This example file illustrates the Random Groups FITS file format which has the keywords NAXIS1 = 0 and GROUPS = T

Demo

The demo directory contains examples of using the library. Each example is located in a separate directory and has two entry points: Delphi and Lazarus project.

• editdata - reading and editing the Data of the FITS file
• edithead - reading and editing the Header of the FITS file
• makeasctable - make a new ASCII-TABLE extension
• makeimage - make a new IMAGE extension from a BITMAP file
• makeumit - make a new FITS file
• markup - markup of the Official Individual Samples of FITS files
• renderimage - render the IMAGE extension of the FITS file

Credits

DeLaFits is used in the CoLiTec project - software package for automatic processing of CCD observations for accurate astrometry and photometry.

The list of known FITS I/O libraries (including DeLaFits) is published in the official resource of the FITS Support Office at NASA/GSFC at NASA/GSFC.

License

MIT © 2013-2021, felleroff, [email protected]