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Rat-Event

Rationale

This crate defines a general event-handling trait, that can be used along with ratatui widgets.

The main idea here is not to try to unify the different event sources.

Instead, provide a trait that can be implemented per event-type.

And as there seem to be widely diverging opinions on what the right key-bindings should be, we add a qualifier type to allow for more than one key-binding. The widget should provide functions for all the interactions anyway, so this mapping can be a one-liner most of the time.

This accomplishes:

• The widget creator can support different event types.
• The widget creator can supply several key bindings.
• The application writer can define ves own key bindings, and as the widget is designed this way it's possible to do this.

Composition

The [HandleEvent::handle] has a generic return type, so each widget can define its own result to convey any state changes.

To allow a minimal level of composition of different return types, there is the trait ConsumedEvent. This allows for early returns, even if the details of the return type are not known.

The [Outcome] enum gives a minimum of information that should be provided. It is very helpful if any outcome from a widget allows conversion to and from [Outcome].

Known qualifiers

These are the predefined qualifiers

• [Regular] - Event-handlers of this kind process all events relevant for a widget. What happens exactly may depend on the internal state of the widget, primarily if it has the input-focus or not.

  See rat-focus for one way to do focus-handling.

• [MouseOnly] - Event-handler for all interactions with a widget that doesn't have the input focus. Usually only mouse-events here, but hot-keys are possible too.

• [Popup] - Specialized event-handler for widgets that draw overlays/popups above other widgets.

• [Dialog] - Specialized even-handler for modal widgets. Such an event-handler consumes all events if active, and prevents other widgets from reacting at all.

Utilities

ct_event!

A neat little thing, that generates pattern matches for mouse events. Has a much terser syntax than composing struct patterns.

select functions

The functions row_at_clicked, column_at_clicked, row_at_drag and column_at_drag allow easier identification which of a slice of Rect is actually meant.

Mouseflags

Identifying double-clicks and mouse-drag is not trivial. This struct helps, add it to your widget state.