Struct StyleExpressionHandle 

pub struct StyleExpressionHandle { /* private fields */ }

Owns one native handle.

A parsed style expression.

See mln_style_expression in the C API reference.

Implementations

impl StyleExpressionHandle

pub fn id(&self) -> u64

Returns the native handle value.

impl StyleExpressionHandle

pub fn create( expression: &str, options: Option<&StyleExpressionOptions>, ) -> Result<StyleExpressionHandle>

Parses a style [expression](https://maplibre.org/maplibre-style-spec/expressions/) to evaluate without a map.

See mln_style_expression_create in the C API reference.

Errors

• Status::InvalidArgument when expression isn’t a valid expression, or its result can’t have the expected type.

pub fn evaluate( &self, inputs: Option<&StyleExpressionInputs<'_>>, ) -> Result<String>

Evaluates a style expression and writes its result as JSON.

A number in the result that isn’t finite becomes null. A color is ["rgba", r, g, b, a], with red, green, and blue from 0 to 255 and alpha from 0 to 1, each exact only to single precision. Formatted text is a ["format", …] expression, an image is {"name": …, "available": …}, padding is [top, right, bottom, left], and a variable anchor offset is [anchor, [x, y], …].

See mln_style_expression_evaluate in the C API reference.

Errors

• Status::InvalidArgument when the expression fails to evaluate, such as when it reads an input that inputs doesn’t set.

pub fn get_info(&self) -> Result<StyleExpressionInfo>

Reads what a style expression’s result depends on.

See mln_style_expression_get_info in the C API reference.

pub fn release(self) -> Result<(), ReleaseError<Self>>

Releases a parsed style expression.

See mln_style_expression_release in the C API reference.

Trait Implementations

impl Debug for StyleExpressionHandle

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

Formats the value using the given formatter.