# Miscellaneous Interfaces

This appendix describes interfaces that are of interest to FormsVBT programmers.

The `ColorName` interface describes the names that are permitted in FormsVBT color-expressions, e.g., `(BgColor "VividTomato")`. While these names are useful to all FormsVBT programmers, the procedures in the interface will be useful primarily to VBTkit programmers.

The `XTrestle` interface provides utility procedures for handling the display and geometry command-line parameters that use the X server.

You should use use `XParam` interface instead of `XTrestle` if your application installs more than one top-level window.

The `FVTypes` interface provides the type definitions of the VBT classes implementing each FormsVBT component. Clients that override the `realize` method will need to access this interface.

The `Rsrc` interface describes how constant data (texts, pixmaps, form-descriptions, etc.) can be combined with a program.

- The ColorName Interface
- The XTrestle Interface
- The XParam Interface
- The FVTypes Interface
- The Rsrc interface