Design

The entry point to DeLaFits is TFitsContainer class from DeLaFitsClasses unit. TFitsContainer aggregates and parses a stream with FITS data (TStream class from the standard library). Composite class TFitsContent contains a methods for direct access to the stream object.

After successful parsing of the stream, the container contains a list of HDU - objects of TFitsUmit class. Each HDU includes the header and data blocks - TFitsUmitHead and TFitsUmitData classes.

HDU extensions implement in separate units as inheritors of TFitsUmit, TFitsUmitHead and TFitsUmitData classes. To identify an HDU instance as an extension, you must call the Container.Reclass() method specifying the extension class.

DeLaFitsImage unit contains the implementation of the IMAGE extension.

DeLaFitsPicture unit contains methods for rendering the IMAGE extension data. Composite class TFitsPictureFrames represents IMAGE data as an array of frames.

DeLaFitsAscTable unit contains the implementation of the ASCII-TABLE extension.

EFitsException (inherited of Exception class) is the base class for all run-time exceptions of DeLaFits. Each DeLaFits exception has Code property.

DeLaFits actively uses the “Lazy Load” pattern with a minimum level of caching of stream data.