Function is_date_axis

crates/plotlars-plotters/src/render/axis.rs:194–198

(axis: &Option<Axis>)

}

pub(super) fn is_date_axis(axis: &Option<Axis>) -> bool {
    axis.as_ref()
        .and_then(|a| a.axis_type.as_ref())
        .is_some_and(|t| matches!(t, AxisType::Date))
}

/// Collect unique x-string labels from scatter/line traces for category/date axes.
pub(super) fn collect_string_x_labels(traces: &[TraceIR]) -> Vec<String> {