Trait cursive::backend::Backend

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

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.

Implementors

impl Backend for cursive::backends::blt::Backend

This is supported on crate feature blt-backend only.

fn name(&self) -> &str

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

fn set_effect(&self, effect: Effect)

fn unset_effect(&self, effect: Effect)

fn has_colors(&self) -> bool

fn screen_size(&self) -> Vec2

fn clear(&self, color: Color)

fn refresh(&mut self)

fn print_at(&self, pos: Vec2, text: &str)

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

impl Backend for cursive::backends::crossterm::Backend

This is supported on crate feature crossterm-backend only.

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

fn refresh(&mut self)

fn has_colors(&self) -> bool

fn screen_size(&self) -> Vec2

fn print_at(&self, pos: Vec2, text: &str)

fn print_at_rep(&self, pos: Vec2, repetitions: usize, text: &str)

fn clear(&self, color: Color)

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

fn set_effect(&self, effect: Effect)

fn unset_effect(&self, effect: Effect)

fn name(&self) -> &str

impl Backend for cursive::backends::curses::n::Backend

This is supported on crate feature ncurses-backend only.

fn name(&self) -> &str

fn screen_size(&self) -> Vec2

fn has_colors(&self) -> bool

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

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

fn set_effect(&self, effect: Effect)

fn unset_effect(&self, effect: Effect)

fn clear(&self, color: Color)

fn refresh(&mut self)

fn print_at(&self, pos: Vec2, text: &str)

fn print_at_rep(&self, pos: Vec2, repetitions: usize, text: &str)

impl Backend for cursive::backends::curses::pan::Backend

This is supported on crate feature pancurses-backend only.

fn name(&self) -> &str

fn screen_size(&self) -> Vec2

fn has_colors(&self) -> bool

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

fn set_effect(&self, effect: Effect)

fn unset_effect(&self, effect: Effect)

fn clear(&self, color: Color)

fn refresh(&mut self)

fn print_at(&self, pos: Vec2, text: &str)

fn print_at_rep(&self, pos: Vec2, repetitions: usize, text: &str)

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

impl Backend for cursive::backends::puppet::Backend

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

fn refresh(&mut self)

fn has_colors(&self) -> bool

fn screen_size(&self) -> Vec2

fn print_at(&self, pos: Vec2, text: &str)

fn clear(&self, clear_color: Color)

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

fn set_effect(&self, effect: Effect)

fn unset_effect(&self, effect: Effect)

impl Backend for cursive::backends::termion::Backend

This is supported on crate feature termion-backend only.

fn name(&self) -> &str

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

fn set_effect(&self, effect: Effect)

fn unset_effect(&self, effect: Effect)

fn has_colors(&self) -> bool

fn screen_size(&self) -> Vec2

fn clear(&self, color: Color)

fn refresh(&mut self)

fn print_at(&self, pos: Vec2, text: &str)

fn print_at_rep(&self, pos: Vec2, repetitions: usize, text: &str)

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

impl Backend for Dummy

pub fn name(&self) -> &str

pub fn refresh(&mut self)

pub fn has_colors(&self) -> bool

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

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

pub fn print_at(&self, XY<usize>, &str)

pub fn print_at_rep(&self, _pos: XY<usize>, _repetitions: usize, _text: &str)

pub fn clear(&self, Color)

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

pub fn set_effect(&self, Effect)

pub fn unset_effect(&self, Effect)