Loading presentation styles

Presentation styles are defined in an XML file with a 4st extension. In order to load the presentation styles, the engine needs to locate the appropriate style file.

By default, the runtime system searches for a file named default.4st in the current directory. If this file does not exist, it searches in the directories defined by the FGLRESOURCEPATH / DBPATH environment variables. If the file was not found using the FGLRESOURCEPATH / DBPATH environment variables, default presentation styles are loaded from the FGLDIR/lib/default.4st file.

Overwrite the default search by loading a specific presentation style file with the ui.Interface.loadStyles() method:

MAIN
  CALL ui.Interface.loadStyles("mystyles")
  ...
END MAIN

This method accepts an absolute path with the 4st extension, or a simple file name without the 4st extension. If you give a simple file name, for example "mystyles", the runtime system searches for the mystyles.4st file in the current directory. If the file does not exist, it searches in the directories defined by the FGLRESOURCEPATH environment variable. If FGLRESOURCEPATH is not defined, it searches in the directories defined by the DBPATH environment variable.

The presentation styles must be defined in a unique 4st file. When loading a styles file with the ui.Interface.loadStyles() method, current styles created from the default file or from a prior load will be replaced. The styles will not be combined when loading several files.

The default styles file located in FGLDIR/lib should not be modified directly: your changes would be lost if you upgrade the product. Make a copy if the original file into the program directory of your application, then modify the copied file.