Struct PolylineItem 

#[non_exhaustive]
pub struct PolylineItem {

    pub positions: Vec<[f32; 3]>,
    pub scalars: Vec<f32>,
    pub strip_lengths: Vec<u32>,
    pub scalar_range: Option<(f32, f32)>,
    pub colourmap_id: Option<ColourmapId>,
    pub default_colour: [f32; 4],
    pub line_width: f32,
    pub id: u64,
    pub node_colours: Vec<[f32; 4]>,
    pub edge_scalars: Vec<f32>,
    pub edge_colours: Vec<[f32; 4]>,
    pub node_radii: Vec<f32>,
    pub node_vectors: Vec<[f32; 3]>,
    pub edge_vectors: Vec<[f32; 3]>,
    pub vector_scale: f32,
    pub appearance: AppearanceSettings,
    pub selected: bool,
}

A polyline (stream tracer) item to render in the viewport.

All streamlines for one source are concatenated into a single vertex buffer. strip_lengths records how many vertices belong to each individual streamline.

Curve network quantities

In addition to the existing per-node scalar path (scalars/colourmap_id), this item supports several curve-network quantities:

• Per-edge scalars (edge_scalars): one value per segment; rendered as a flat constant colour per edge (both endpoints share the same LUT value).
• Per-node colours (node_colours): direct RGBA per node; takes priority over scalar-driven colouring.
• Per-edge colours (edge_colours): direct RGBA per segment; takes priority over edge scalars.
• Per-node radius (node_radii): per-node line width in pixels; overrides the global line_width.
• Node vectors (node_vectors): world-space 3-D arrows at each node, rendered automatically as GlyphItem arrows.
• Edge vectors (edge_vectors): world-space 3-D arrows at each segment midpoint, also rendered as GlyphItem arrows.

Colour priority per segment: node_colours/edge_colours (direct) > edge_scalars > scalars (per-node) > default_colour.

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

positions: Vec<[f32; 3]>

World-space positions for all streamlines, concatenated.

scalars: Vec<f32>

Per-node scalar values (same length as positions). Empty = no scalar colouring.

strip_lengths: Vec<u32>

Number of vertices per individual streamline strip.

scalar_range: Option<(f32, f32)>

Scalar range for LUT mapping. None = auto from min/max of scalars or edge_scalars.

colourmap_id: Option<ColourmapId>

Colourmap for scalar colouring. None = viridis.

default_colour: [f32; 4]

Fallback colour when no scalar or direct-colour data is provided.

line_width: f32

Global line width in pixels. Used when node_radii is empty.

id: u64

Unique ID for identification. 0 = not pickable.

node_colours: Vec<[f32; 4]>

Per-node direct RGBA colours. Length must match positions. Empty = not used. Takes priority over scalar-driven colouring when non-empty.

edge_scalars: Vec<f32>

Per-edge scalar values. Length = total segment count across all strips (sum of strip_lengths[i] - 1). Used when scalars is empty; both endpoints of each segment share the same LUT value (flat constant colour per edge).

edge_colours: Vec<[f32; 4]>

Per-edge direct RGBA colours. Length = total segment count. Takes priority over edge_scalars when non-empty.

node_radii: Vec<f32>

Per-node line width in pixels. Length must match positions. When non-empty, overrides the global line_width; adjacent endpoints are linearly interpolated along each segment.

node_vectors: Vec<[f32; 3]>

Per-node world-space vectors. Length must match positions. When non-empty the renderer automatically generates a GlyphItem (arrows at node positions).

edge_vectors: Vec<[f32; 3]>

Per-edge world-space vectors. Length = total segment count. When non-empty the renderer automatically generates a GlyphItem (arrows at segment midpoints).

vector_scale: f32

Scale applied to generated arrow glyphs from node_vectors/edge_vectors.

appearance: AppearanceSettings

Per-item appearance overrides (hidden, unlit, opacity, wireframe).

selected: bool

Whether this polyline set is selected at object level. When true and InteractionFrame::outline_selected is set, the renderer draws a smooth outline ring around the node positions. Default: false.

Trait Implementations

impl Clone for PolylineItem

fn clone(&self) -> PolylineItem

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Default for PolylineItem

fn default() -> Self

Returns the “default value” for a type.