Struct EvaluationContext 

pub struct EvaluationContext {
    pub zoom: Option<f64>,
    pub feature: Feature,
    pub global_state: BTreeMap<String, Value>,
    pub available_images: Vec<String>,
    pub canonical: Option<(u32, u32, u32)>,
    pub heatmap_density: Option<f64>,
    pub elevation: Option<f64>,
    pub line_progress: Option<f64>,
}

Everything an expression can read while evaluating: global parameters such as zoom, the current Feature, and the shared global-state map read by the global-state operator.

Fields

zoom: Option<f64>

feature: Feature

global_state: BTreeMap<String, Value>

available_images: Vec<String>

Image names known to be available (used by the image operator).

canonical: Option<(u32, u32, u32)>

The canonical tile (z, x, y) the feature belongs to, if any.

heatmap_density: Option<f64>

Heatmap density (heatmap-density), 0..1.

elevation: Option<f64>

Terrain elevation (elevation).

line_progress: Option<f64>

Line progress along a symbol/line (line-progress), 0..1.

Implementations

impl EvaluationContext

pub fn new() -> EvaluationContext

pub fn with_zoom(self, zoom: f64) -> EvaluationContext

pub fn with_feature(self, feature: Feature) -> EvaluationContext

pub fn with_global_state( self, state: BTreeMap<String, Value>, ) -> EvaluationContext

Trait Implementations

impl Clone for EvaluationContext

fn clone(&self) -> EvaluationContext

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for EvaluationContext

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

Formats the value using the given formatter.

impl Default for EvaluationContext

fn default() -> EvaluationContext

Returns the “default value” for a type.