Function draw 

pub fn draw(
    layout: &GraphLayout,
    lanes: &[String],
    nodes: &[DrawNode],
    edges: &[DrawEdge],
    style: &GraphStyle,
    theme: Theme,
) -> GGPlot

Draw a laid-out graph on a layout.w × layout.h px canvas: lanes names the layout’s bands, nodes and edges are in the layout’s order. theme is the base (a void theme; the legend is turned off). Render the result with e.g. render_svg_native_at(0.0, 0.0, w, h) at the canvas size rounded up.