Struct Headless 

pub struct Headless {
    grid: Grid,
    cursor_visible: bool,
    cursor_pos: Pos,
    event_queue: VecDeque<Event>,
}

In-memory backend for testing. Stores presented content and allows injecting synthetic events.

Fields

grid: Grid

cursor_visible: bool

cursor_pos: Pos

event_queue: VecDeque<Event>

Implementations

impl Headless

pub fn new(width: u16, height: u16) -> Self

Creates a new headless backend of the given dimensions.

pub const fn grid(&self) -> &Grid

Returns a reference to the grid.

pub const fn cursor_visible(&self) -> bool

Returns the cursor visibility.

pub const fn cursor_position(&self) -> Pos

Returns the cursor position.

pub fn push_event(&mut self, event: Event)

Injects a synthetic event into the queue.

pub fn format_view(&self) -> String

Converts the current grid state into a readable string for snapshot testing.

Space cells are rendered as · so layout is visible in text diffs.

Trait Implementations

impl Backend for Headless

fn draw<'a, I>(&mut self, content: I)

where I: Iterator<Item = (Pos, &'a Tile)>,

Draw changed cells to the output surface.

fn resize(&mut self, size: Size)

Notify the backend of a terminal resize.

fn flush(&mut self)

Flush buffered output to the display.

fn size(&self) -> Size

Return current display dimensions.

fn clear(&mut self)

Clear the entire display.

fn poll_event(&mut self, _timeout: Duration) -> Option<Event>

Poll for an input event, waiting up to timeout.

fn push_event(&mut self, event: Event)

Push an event into the backend’s event buffer.

fn set_cursor_visible(&mut self, visible: bool)

Show or hide the cursor.

fn set_cursor_position(&mut self, position: Pos)

Move the cursor to a position.

fn draw_layers<'a, I>(&mut self, content: I)

where I: Iterator<Item = (u8, Pos, &'a Tile)>,

Draw changed cells across all layers.

fn needs_full_frame(&self) -> bool

Returns true if the backend needs the entire frame (all cells on all layers) on every call to draw_layers, rather than just the changed cells.

fn is_connected(&self) -> bool

Returns false if the backend has been disconnected from its output (e.g. the window was closed). The game loop should terminate when this returns false.