Struct ExprEvalContext 

pub struct ExprEvalContext<'a> {
    pub zoom: f32,
    pub pitch: f32,
    pub properties: Option<&'a FeatureProperties>,
    pub feature_state: Option<&'a FeatureState>,
}

Full evaluation context for expressions.

Carries zoom level, optional feature properties (for data-driven styling), and optional feature state (for interactive hover/selection styling).

Fields

zoom: f32

Current map zoom level (0–22+).

pitch: f32

Current camera pitch in degrees.

properties: Option<&'a FeatureProperties>

Per-feature properties (from GeoJSON / MVT).

None when evaluating at the layer level (no specific feature).

feature_state: Option<&'a FeatureState>

Per-feature mutable state (hover, selected, etc.).

None when feature state is not available.

Implementations

impl<'a> ExprEvalContext<'a>

pub fn zoom_only(zoom: f32) -> Self

Create a zoom-only context.

pub fn with_feature(zoom: f32, properties: &'a FeatureProperties) -> Self

Create a context with feature properties for data-driven styling.

pub fn and_state(self, state: &'a FeatureState) -> Self

Add feature state to this context.

pub fn and_pitch(self, pitch: f32) -> Self

Add pitch to this context.

pub fn get_property(&self, key: &str) -> Option<&PropertyValue>

Look up a feature property by key.

pub fn get_state(&self, key: &str) -> Option<&PropertyValue>

Look up a feature-state value by key.

Trait Implementations

impl<'a> Clone for ExprEvalContext<'a>

fn clone(&self) -> ExprEvalContext<'a>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<'a> Debug for ExprEvalContext<'a>

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

Formats the value using the given formatter.

impl<'a> Copy for ExprEvalContext<'a>