Introduction

This paper is an introduction to the ``Graphical User Interface'' (GUI) of FIT2D, and an overview of the main functionality. More detailed descriptions of particular commands are available in the FIT2D ``Reference Manual'' (Hammersley, 1995). Basic knowledge of modern computer systems is assumed, but no detailed knowledge of a particular operating system is needed.

The manner in which the user works with the GUI is described. The GUI is designed to make easily accessible the most used functionality which is available within FIT2D. To achieve this, functionality has been arranged into different ``interfaces'' for different scientific areas. Figure 1 shows the menu for the present choice of ``scientific interfaces''. (Further interfaces are likely to be added in future versions.) It should be emphasized that data can be moved from one interface to another without restriction e.g. 2-D Powder diffraction data could be input in the IMAGE PROCESSING (GENERAL) menu, and manipulated, then Debye-Scherrer rings could be integrated within the POWDER DIFFRACTION (2-D) menu.

Figure 1: The FIT2D Scientific Interfaces Main Menu

By clicking on the different ``buttons'' the user enters the different ``interfaces''. The buttons are:

? The question mark in this menu, and other menus gives a brief description of each of the available choices.

HELP The ``HELP'' button enters the ``context'' related help associated with the menu. In this case there is information describing the different available interfaces. Clicking on ``HELP'' enters a ``pager'' which allows the user to scroll down and up the help information.

IMAGE PROCESSING (GENERAL) Is an interface for general purpose image processing and display operations on data input from a file.

KEYBOARD INTERFACE This enters the ``keyboard'' command-line interface to FIT2D. Certain functionality is presently only available from this interface.

MFIT (MULTIPLE 1-D FITTING) This interface allows 1-D ``peak'' functions such as Gaussian, Lorentzian, and Voigt functions to be fitted to data along with other functions such as a polynomial ``background'' function, and exponential decay or trigonometric functions. The fit model may be fitted repeatedly to a whole series of 1-D datasets. (This provides the same functionality as was previously available through the program MFIT (Hammersley, 1989).)

ON-LINE CRYSTALLOGRAPHY This interface allows on-line display and examination of crystallographic data, with the option of automatic updating of new image data as they are obtained. Simple statistics to evaluate data quality are produced.

POWDER DIFFRACTION (2-D) This interface specialises in the integration of Debye-Scherrer rings from 2-D detectors, to 1-D ``2-theta'' scans, and to other scans. This is useful for standard powder refinement, but is also useful for texture analysis and other types of integrations and ``scans'', and is used for small angle scattering data.

EXIT FIT2D Allows FIT2D to be exited, after confirmation.