Trait cursive::view::View [−] [src]

pub trait View {
    fn draw(&self, printer: &Printer);

    fn on_event(&mut self, Event) -> EventResult { ... }
    fn get_min_size(&mut self, constraint: Vec2) -> Vec2 { ... }
    fn needs_relayout(&self) -> bool { ... }
    fn layout(&mut self, Vec2) { ... }
    fn find(&mut self, &Selector) -> Option<&mut Any> { ... }
    fn take_focus(&mut self, source: Direction) -> bool { ... }
}

Main trait defining a view behaviour.

Required Methods

fn draw(&self, printer: &Printer)

Draws the view with the given printer (includes bounds) and focus.

Provided Methods

fn on_event(&mut self, Event) -> EventResult

Called when a key was pressed. Default implementation just ignores it.

fn get_min_size(&mut self, constraint: Vec2) -> Vec2

Returns the minimum size the view requires with the given restrictions.

If the view is flexible (it has multiple size options), it can try to return one that fits the given constraint. It's also fine to ignore it and return a fixed value.

fn needs_relayout(&self) -> bool

Returns true if the view content changed since last layout phase.

This is mostly an optimisation for views where the layout phase is expensive.

  • Views can ignore it and always return true (default implementation). They will always be assumed to have changed.
  • View Groups can ignore it and always re-layout their children.
    • If they call get_min_size or layout with stable parameters, the children may cache the result themselves and speed up the process anyway.

fn layout(&mut self, Vec2)

Called once the size for this view has been decided,

View groups should propagate the information to their children.

fn find(&mut self, &Selector) -> Option<&mut Any>

Finds the view pointed to by the given path.

Returns None if the path doesn't lead to a view.

fn take_focus(&mut self, source: Direction) -> bool

This view is offered focus. Will it take it?

source indicates where the focus comes from. When the source is unclear, Front is usually used.

Implementors