Module widgetry::app_state

A widgetry application splits its state into two pieces: global shared state that lasts for the entire lifetime of the application, and a stack of smaller states, only one of which is active at a time. For example, imagine an application to view a map. The shared state would include the map and pre-rendered geometry for it. The individual states might start with a splash screen or menu to choose a map, then a map viewer, then maybe a state to drill down into pieces of the map.

Structs

• App 🔒
• SimpleStateWrapper

Enums

• DrawBaselayer
  Before State::draw is called, draw something else.
• Transition
  When a state responds to an event, it can specify some way to manipulate the stack of states.

Traits

• SharedAppState
  Any data that should last the entire lifetime of the application should be stored in the struct implementing this trait.
• SimpleState
  Many states fit a pattern of managing a single panel, handling mouseover events, and other interactions on the map. Implementing this instead of State reduces some boilerplate.
• State
  A temporary state of an application. There’s a stack of these, with the most recent being the active one.