Trait cursive::view::View[][src]

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

    fn layout(&mut self, Vec2) { ... }
fn needs_relayout(&self) -> bool { ... }
fn required_size(&mut self, constraint: Vec2) -> Vec2 { ... }
fn on_event(&mut self, Event) -> EventResult { ... }
fn call_on_any<'a>(&mut self, _: &Selector, _: AnyCb<'a>) { ... }
fn focus_view(&mut self, &Selector) -> Result<(), ()> { ... }
fn take_focus(&mut self, source: Direction) -> bool { ... }
fn important_area(&self, view_size: Vec2) -> Rect { ... } }

Main trait defining a view behaviour.

This is what you should implement to define a custom View.

Required Methods

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

This is the only required method to implement.

Provided Methods

Called once the size for this view has been decided.

It can be used to pre-compute the configuration of child views.

View groups should propagate the information to their children.

At this point, the given size is final and cannot be negociated. It is guaranteed to be the size available for the call to draw().

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 required_size or layout with stable parameters, the children may cache the result themselves and speed up the process anyway.

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

This is the main way a view communicate its size to its parent.

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.

Default implementation always return (1,1).

Called when an event is received (key press, mouse event, ...).

You can return an EventResult, with an optional callback to be run.

Default implementation just ignores it.

Runs a closure on the view identified by the given selector.

See Finder::call_on for a nicer interface, implemented for all views.

If the selector doesn't find a match, the closure will not be run.

Default implementation is a no-op.

Moves the focus to the view identified by the given selector.

Returns Ok(()) if the view was found and selected.

Default implementation simply returns Err(()).

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.

Default implementation always return false.

What part of the view is important and should be visible?

When only part of this view can be visible, this helps determine which part.

It is given the view size (same size given to layout).

Default implementation return the entire view.

Implementors