[−][src]Trait cursive::backend::Backend

pub trait Backend {
    fn poll_event(&mut self) -> Option<Event>;

    fn finish(&mut self);

    fn refresh(&mut self);

    fn has_colors(&self) -> bool;

    fn screen_size(&self) -> XY<usize>;

    fn print_at(&self, pos: XY<usize>, text: &str);

    fn clear(&self, color: Color);

    fn set_color(&self, colors: ColorPair) -> ColorPair;

    fn set_effect(&self, effect: Effect);

    fn unset_effect(&self, effect: Effect);

    fn print_at_rep(&self, pos: XY<usize>, repetitions: usize, text: &str) { ... }

    fn name(&self) -> &str { ... }
}

Trait defining the required methods to be a backend.

A backend is the interface between the abstract view tree and the actual input/output, like a terminal.

It usually delegates the work to a terminal-handling library like ncurses or termion, or it can entirely simulate a terminal and show it as a graphical window (BearLibTerminal).

When creating a new cursive tree with Cursive::new(), you will need to provide a backend initializer - usually their init() function.

Backends are responsible for handling input and converting it to Event. Input must be non-blocking, it will be polled regularly.

Required methods

fn poll_event(&mut self) -> Option<Event>

Polls the backend for any input.

Should return immediately:

  • None if no event is currently available.
  • Some(event) for each event to process.

fn finish(&mut self)

Prepares to close the backend.

This should clear any state in the terminal.

fn refresh(&mut self)

Refresh the screen.

This will be called each frame after drawing has been done.

A backend could, for example, buffer any print command, and apply everything when refresh() is called.

fn has_colors(&self) -> bool

Should return true if this backend supports colors.

fn screen_size(&self) -> XY<usize>

Returns the screen size.

fn print_at(&self, pos: XY<usize>, text: &str)

Main method used for printing

fn clear(&self, color: Color)

Clears the screen with the given color.

fn set_color(&self, colors: ColorPair) -> ColorPair

Starts using a new color.

This should return the previously active color.

Any call to print_at from now on should use the given color.

fn set_effect(&self, effect: Effect)

Enables the given effect.

Any call to print_at from now on should use the given effect.

fn unset_effect(&self, effect: Effect)

Disables the given effect.

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Provided methods

fn print_at_rep(&self, pos: XY<usize>, repetitions: usize, text: &str)

Efficient method to print repetitions of the same text.

Usually used to draw horizontal lines/borders.

It is a small optimization to avoid moving the cursor after each step.

fn name(&self) -> &str

Returns a name to identify the backend.

Mostly used for debugging.

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Implementors

impl Backend for Dummy[src]

impl Backend for cursive::backends::curses::n::Backend[src]

impl Backend for cursive::backends::dummy::Backend[src]

impl Backend for cursive::backends::puppet::Backend[src]

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