Multiple theme engine graphical user interface architecture

1. In a graphical user interface, a method for rendering objects and handling behavior of said objects comprising the steps of:

providing a plurality of themes, each theme controlling an appearance and behavior of objects rendered on said graphical user interface, wherein at least one of said appearance and said behavior is controlled differently for an object when said graphical user interface is operated in accordance with one theme than when said graphical user interface is operated in accordance with another theme;

providing a plurality of theme engines, each theme engine associated with a different theme type, wherein at least one of said theme engines is hard-coded and at least one of said theme engines is a data-driven, parametric engine;

selecting a theme from among said plurality of themes;

identifying one of said plurality of theme engines associated with said selected theme; and

loading, by said identified theme engine, theme data for operating said graphical user interface in accordance with said selected theme.

2. The method of claim 1, further comprising the steps of:

providing a plurality of theme data files, each associated with a different theme and each accessible by said data-driven theme engine.

3. The method of claim 1, wherein said hard-coded theme engine can manage only one theme.

4. A computer system comprising:

a processor for performing control functions and processing data;

a display for outputting data received from said processor and for receiving input from a user of said computer system via a graphical user interface; and

a plurality of theme engines each capable of rendering a theme by drawing an object on said graphical user interface, wherein a selected one of said theme engines is commanded to draw said object based upon a theme selection coordinated by said processor.

5. The computer system of claim 4, wherein one of said plurality of theme engines is hard-coded.

6. The computer system of claim 5, wherein said hard-coded theme engine has a data file associated therewith that includes only nominal data.

7. The computer system of claim 4, wherein one of said plurality of theme engines is a data-driven, parametric engine.

8. The computer system of claim 7, wherein a plurality of theme data files are stored on a computer-readable medium, each of said plurality of theme data files having a same format which is accessible by said data-driven parametric engine.

9. A method for selecting themes operable to control appearance and behavior of objects rendered on a graphical user interface comprising the steps of:

providing an appearance control panel;

providing a plurality of theme engines, including a default theme engine and at least one other theme engine;

selecting, by said appearance control panel, a theme;

loading said selected theme using one of said plurality of theme engine, unless a valid theme data file cannot be retrieved for said selected theme; and

otherwise, loading a default theme using said default theme engine.

10. The method of claim 9, wherein said default theme engine is hard-coded.

11. The method of claim 9, wherein said default theme engine is data-driven.

12. A computer-readable medium having stored thereon computer-readable information for performing the steps of:

providing a plurality of theme engines, each theme engine capable of rendering objects according to at least one theme;

selecting, by one of a user and a program, a current theme; and

using a theme engine associated with said current theme to render objects in a graphical user interface according to said current theme.

13. The computer-readable medium of claim 12, wherein said theme provides information relating to object geometries and fill patterns for said objects.

14. The computer-readable medium of claim 12, wherein said step of providing further comprises the step of:

providing a hard-coded theme engine and a data-driven theme engine.

15. The computer-readable medium of claim 12, wherein said step of selecting further comprises the step of:

creating a appearance control panel on said graphical user interface; and

receiving input from said user in said appearance control panel as an indication of said selected current theme.

16. The computer-readable medium of claim 12, wherein said step of using a theme engine associated with said current theme further comprises the steps of:

loading, by said theme engine, a data table indicating said object geometries and fill patterns for said current theme; and

drawing, by a graphics subsystem, objects on said graphical user interface using information in said data table.