Struct UiContext 

pub struct UiContext {
    pub appearance: Appearance,
    pub charset: Charset,
    pub graphics: Graphics,
    pub jamo_width: JamoWidth,
    pub theme: Theme,
    pub elements: Elements,
    pub now: Duration,
    pub revision: u64,
    pub loader: Option<ImageLoader>,
}

Presentation context threaded through parse, layout, and paint.

Fields

appearance: Appearance

Terminal-reported dark or light background appearance.

charset: Charset

Glyph capability tier.

graphics: Graphics

Terminal image rendering capability.

jamo_width: JamoWidth

Hangul Compatibility Jamo width policy.

Prefer UiContext::set_jamo_width over direct assignment: the method also updates the process-wide hot-path setting and invalidates width caches.

theme: Theme

Semantic color palette.

elements: Elements

Custom element registry.

now: Duration

Presentation clock of the pass in flight: crate::Ui::tick advances it so size transitions can be sampled during layout, where no crate::PaintCtx exists. Excluded from equality — a moving clock must never read as a context change.

revision: u64

Cache-invalidation revision, advanced by crate::Ui::set_context when a differing context is applied. Geometry and render memos fold it into their keys so output derived from the previous context is discarded. Excluded from equality, like the clock.

loader: Option<ImageLoader>

Off-thread image decoder. None decodes inline during layout for deterministic tests and bare synchronous hosts. crate::App installs one before building the crate::Ui.

Implementations

impl UiContext

pub fn set_jamo_width(&mut self, width: JamoWidth) -> bool

Applies a Hangul Compatibility Jamo policy process-wide.

Returns whether the effective configuration changed. Width-derived caches observe that change through [crate::rich::width_config_epoch].

pub fn apply_terminal_caps(&mut self, caps: &TerminalCaps) -> bool

Applies the detected terminal’s capabilities: graphics tier, glyph charset, Compatibility Jamo policy, and background appearance.

Capability values are 0 for platform default, 1 for narrow, and 2 for wide.

pub fn with_terminal_caps(self, caps: &TerminalCaps) -> Self

Returns this context configured for the detected terminal.

Examples found in repository

examples/footers.rs (line 55)

async fn main() -> io::Result<()> {
	let caps = detect();
	let charset = UiContext::default().with_terminal_caps(&caps).charset;
	let mut terminal = Terminal::enter(TerminalOptions::new(caps).mouse(true))?;
	let mut renderer = Renderer::new(TtyOut::new()?);
	renderer.apply_caps(&caps)?;
	match run(&mut terminal, &mut renderer, charset).await {
		Ok(()) => terminal.leave_alt(),
		Err(error) => {
			let _ = terminal.leave_alt();
			Err(error)
		},
	}
}

examples/chat/main.rs (line 57)

async fn main() -> io::Result<()> {
	let caps = detect();
	// One detected presentation context — charset, graphics, appearance —
	// threads through every scene instead of per-module hardcodes.
	let ctx = UiContext::default().with_terminal_caps(&caps);
	let mut terminal =
		Terminal::enter(TerminalOptions::new(caps).cursor_style(CursorStyle::BlinkingBar))?;
	let mut renderer = Renderer::new(TtyOut::new()?);
	renderer.apply_caps(&caps)?;
	run(&mut terminal, &mut renderer, &ctx).await
}

Trait Implementations

impl Clone for UiContext

fn clone(&self) -> UiContext

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for UiContext

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for UiContext

fn default() -> Self

Returns the “default value” for a type.

impl Eq for UiContext

impl PartialEq for UiContext

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.