LayoutConfig

class braincell.vis.LayoutConfig(collision_margin_um=2.0, collision_retry_limit=8, stem_collision_window=24, collision_cell_size_um=20.0, default_bend_fraction=0.4, balloon_bend_fraction=0.22, fan_bend_fraction=0.24, radial_bend_fraction=0.25, stem_root_full_span_rad=2.6179938779914944, stem_root_group_span_rad=2.0943951023931953, balloon_root_span_rad=3.141592653589793, balloon_child_span_rad=2.0943951023931953, balloon_type_split_span_rad=1.9198621771937625, fan_root_left_span_rad=1.6580627893946132, fan_root_middle_upper_span_rad=1.2217304763960306, fan_root_middle_lower_span_rad=1.2217304763960306, fan_root_right_span_rad=1.6580627893946132, radial_root_span_rad=6.283185307179586, radial_child_span_rad=2.6179938779914944, legacy_root_child_span_rad=2.0943951023931953, fan_root_left_max_parent_x=0.02, fan_root_middle_min_parent_x=0.35, fan_root_middle_max_parent_x=0.65, stem_collision_weight=100.0, stem_tail_delta_weight=3.0, stem_settle_delta_weight=0.8, stem_overturn_weight=6.0, stem_trunk_tail_delta_weight=0.75, stem_side_opening_weight=2.0)

Configurable parameters for the 2D layout engine.

Parameters:

• collision_margin_um (float) – Radius of the “too close” bubble around each placed branch. Any candidate whose closest approach to a previously-placed branch is below this threshold incurs a soft penalty of margin - distance per offending segment pair. Proper intersections incur a flat 1000.0 penalty regardless.

• collision_retry_limit (int) – Maximum number of candidate placements the stem-linear solver tries before accepting the best-so-far. Raising this makes dense morphologies cleaner at the cost of linear runtime.

• stem_collision_window (int) – How many of the most recently placed branches the stem-tree solver checks for collisions against. With the spatial-hash backend the cost per candidate is roughly linear in the number of segments actually within collision_cell_size_um of the candidate; a larger window is therefore affordable but still bounded to avoid rescoring the whole tree at deep forks.

• collision_cell_size_um (float) – Grid cell size for the 2D spatial-hash collision backend in _collision. Should be a small multiple of the typical branch segment length; too small and the hash wastes memory with sparsely-populated cells, too large and queries degrade toward the O(n²) brute force.

• default_bend_fraction (float) – Fraction of a branch’s total length used to bend from the attach tangent to the target angle in the stem-linear and legacy families.

• balloon_bend_fraction (float) – Same idea for the balloon family. Smaller values make each branch curve more sharply near its root.

• fan_bend_fraction (float) – Same idea for the fan family.

• radial_bend_fraction (float) – Same idea for the radial_360 family.

• fan_root_left_span_rad (float) – Angular span used for root children attached at the extreme left side of the soma.

• fan_root_middle_upper_span_rad (float) – Angular span used for the upper root sector for center-attached children.

• fan_root_middle_lower_span_rad (float) – Angular span used for the lower root sector for center-attached children.

• fan_root_right_span_rad (float) – Angular span used for root children attached away from the center/right side of the soma.

• fan_root_left_max_parent_x (float) – Maximum parent_x classified into the left sector.

• fan_root_middle_min_parent_x (float) – Inclusive lower bound of the center band.

• fan_root_middle_max_parent_x (float) – Inclusive upper bound of the center band.

• stem_root_full_span_rad (float) – Full angular span used for root children when root_layout is not 'type_split' (all children packed into one arc).

• stem_root_group_span_rad (float) – Angular span allocated per group (axon group or dendrite group) when root_layout='type_split'. The two groups sit on opposite half-planes centered on ±π/2.

• balloon_root_span_rad (float) – Angular span used by the balloon family for the root fork when not splitting by type.

• balloon_child_span_rad (float) – Angular span used by the balloon family for each non-root fork, centered on the parent’s tangent.

• balloon_type_split_span_rad (float) – Per-group span for the balloon family when root_layout='type_split'.

• radial_root_span_rad (float) – Angular span used by the radial_360 family for the root fork (defaults to a full 2π).

• radial_child_span_rad (float) – Angular span used by the radial_360 family for each non-root fork.

• legacy_root_child_span_rad (float) – Angular span for root children in the legacy layout.

• stem_collision_weight (float) – Weight applied to the raw collision score when computing the total stem-tree score. With collision_weight=100 a single intersection (score 1000.0) contributes 100 000 to the total, which dominates every other term — intentional, since intersections are always worse than a bad angle.

• stem_tail_delta_weight (float) – Weight on the tail-angle deviation from the desired target. Increase to make the engine more faithful to the target angle at the cost of possible overlap.

• stem_settle_delta_weight (float) – Weight on the “settle” angle deviation from the tail. Keeps the mid-branch from over-rotating between launch and tail.

• stem_overturn_weight (float) – Weight on turns wider than π/2 between launch and tail. Discourages hairpin turns.

• stem_trunk_tail_delta_weight (float) – Extra per-trunk penalty on tail deviation from the attach tangent. Keeps trunks visually continuous across a fork.

• stem_side_opening_weight (float) – Extra per-side penalty that rewards launches “opening away” from the desired tail by at least max(|desired|, 55°).