Graphical User Interface

The graphical user interface functions of the ToolKit are based on the Xlib public domain library, which is an integrated part of the X Windows system. The user interface across all modules shares a number of common characteristics, that together define the look and feel of the ACA ToolKit and the applications developed with it.

Any major module has its own full-screen start-up page; this includes a header bar with a set of icons and the name of the module (default driven). At the bottom of the screen is a message bar, that contains status information and prompts for the user.

Every screen must at least contain two icons, namely an information icon and an exit icon which returns the user the previous level of the application or to the UNIX systems shell from the top level, respectively. The information icon invokes the hypertext help and explain system. If no corresponding text file is found in $PROJECT/data/explain, an alert box is shown that indicates the name of the missing file to the user. At this point, the user can acknowledge and Continue, or Quit the application and create the missing file.

Every module consists of

  1. status information,
  2. set of options the user can invoke,
  3. and the results of the current set of specifications;

For every module, a default set of options is defined. This default controls the initial results or status, eg., a default scenario for a model.

Options the user can invoke are either icons, items in a selector (a list of one or two line text items), specific header parts of windows, or symbols on a map. In most cases, windows that represent user selectable options are identified by a 3D frame. Options (icons, windows, selector lines) provide optical feedback (highlighting, change of color) when the mouse pointer is positioned in or over them, to indicate that they represent selectable options. In many cases, the message bar at the bottom of the screen provides additional guidance to the user by identifying options. Options are always selected with the mouse, by positioning the mouse pointer and clicking the left mouse button.

Wherever possible, the left part of the screen is used for status information and further options, the right part for graphical display such as maps and diagrams. Icon menus are usually located in the bottom part of the screen. For pop-up windows, both information and exit icons can be found in the header bar of the window. Pop-up windows are usually identified by a shadow-style frame, that sets them off from the underlying set of windows.

In addition to the use of location and highlighting, colors are used to indicate functionality. Numbers that can be selected for editing in a selector are blue; hot keys in the hypertext are also blue.


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