One of the most noteworthy of the modules in the Code module is DisplayManager. The Display Manager handles drawing the system pages in your application, as well as its title bar, navigation bar, and all other drawing tasks in the system. Nothing is drawn on the screen in a VTS system that is not called directly or indirectly from the Display Manager.
By convention, the Display Manager accesses graphic pages from a set of modules stored in the Pages directory within your application directory (i.e. "VTS\MyApplication\Pages\"). These modules are defined in the application's AppMod.src root file, in the PAGES variable class (see AppMod.src Root File for a Standard Application). The PAGES variable class in AppMod.src is automatically updated each time you add a new page to your application.
The instance of the Display Manager is created by specifying the Display Manager module declaration in the SERVICES section of AppMod.src (see AppMod.src Root File for a Standard Application). Any modules declared in this section result in a variable of the same name being defined in the VTS Code module, with the value set to the object value of the running copy of the module. Such modules are launched with no parameters.
The name of the Display Manager module is "DisplayManager". Code accessing the Display Manager can reference the variable "\DisplayManager" to obtain the object value, which can then be used to scope into the Display Manager to set and view local values.
The Page variable defined in the code is used by the Display Manager to change graphic pages. This Page variable must be defined in the application's AppMod.src root file (see AppMod.src Root File for a Standard Application). An example is displayed below:
[ (PAGES) {=== Modules that are graphic pages and dialogs ===}
MyNewPage Module "Pages\MyNewPage.SRC";
]
The Display Manager has a module named LaunchWindow, that will display a graphic page as a separate windowed page, rather than as a full screen in the Display Manager. This allows multiple pages to be open and displayed at the same time. For example, the windowed version of the Trends page that is opened by default when a user clicks any analog input tag's drawing method can be open on top of the system page from which it was called.
The Display Manager should have a variable named "Page" defined. This Page variable can be set by an external module to force the window to change to a given page if permitted by the Security Manager. It is up to the Display Manager to enforce the security of page changes.