Line

Line plots connect one value per timestamp. Start with the series overview for identity and lifecycle.

Data

Use Bar::from_value(time, value) for a scalar. OHLC bars also work: the main series uses ChartConfig::price_source, which defaults to close; added line series always use close. A Bar::whitespace point leaves a gap. Do not encode a missing value as zero.

Choose ChartType::Line, LineWithMarkers or StepLine. Steps run horizontally from the previous point to the new point’s time, then vertically to its value.

Style and running result

The scene extracts closes from the shared sample history into scalar bars and draws a marker at each one.

A line with point markersOpen full size

Zoom in to distinguish each scalar value and its connecting segment.

The interactive example needs JavaScript and WebAssembly. You can still use the chart setup alongside it.

series_line.rs

use egui_charts::Chart;

pub fn line() -> Chart {
    use egui_charts::{ChartType, model::Bar, widget::SeriesId};
    let mut chart = crate::first_chart::first_chart();
    let values = chart
        .bars(SeriesId::MAIN)
        .iter()
        .map(|bar| Bar::from_value(bar.time, bar.close))
        .collect();
    chart.set_data(SeriesId::MAIN, values);
    chart.set_chart_type(ChartType::LineWithMarkers);
    chart.config_mut().show_volume = false;
    chart.config_mut().show_legend_volume = false;
    let mut params = chart.chart_type_params().clone();
    params.styles.line_with_markers.width = 2.0;
    params.styles.marker_radius = 3.0;
    chart.set_chart_type_params(params);
    chart
}

The compiled setup is in series.rs. ChartTypeStyles keeps line, step_line and line_with_markers independent. Each LinePlotStyle sets colour, width, dash style and straight or curved connections. Step line ignores curvature. marker_radius controls the point circles; crosshair_marker_radius and last_price_animation control hover and last-price markers.

For an added series, use SeriesOptions::color and width. Added lines use solid straight segments, or steps for StepLine; they do not expose the main line’s dash/curve options. Per-point BarColors::color colours the outgoing segment or marker. All three line types can be added series.

Continue to area to fill beneath the line, or baseline to compare it with a reference.