pack

Places its children so that their enclosing circles touch and do not overlap. This is circle packing. With a by, pack makes one child per group. Without a by, it makes one child per row. Two pack operators in a row give a nested packing.

from gofish import chart, circle, circles, pack

chart(seafood).flow(
    pack(by="lake"),
    pack(method=circles()),
).mark(circle(r=12, fill="species")).render(w=420, h=420)

Signature

pack(*, by=None, **options) -> Operator
pack(children, **options) -> Mark
circles() -> dict

Combinator form

Given a list of marks, pack packs those marks instead of rows of data. It returns a mark, so a pack can hold another pack. It takes no by.

from gofish import circle, ellipse, pack

pack([
    circle(r=60),
    ellipse(w=90, h=44),
    pack([circle(r=26), circle(r=18), circle(r=14)]),
]).render(w=420, h=420)

Parameters

Circle packing: place the flow's groups (or rows) so their enclosing circles touch without overlapping. Children keep their pixel size; the pack does not fit itself to the available space yet (#967).

Option	Type	Default	Description
by	str | Any		Field to partition rows by (like spread/scatter); also accepts a field(...) accessor carrying domain ops (sort/reverse/bin/dropNulls). Without by, one child per row.
method	dict	{"kind":"circles"}	The packing strategy, made by a function call: circles() packs each child's enclosing circle with d3's front-chain algorithm.

Strategies

method holds the packing strategy. You make a strategy with a function call.

• circles() packs each child's enclosing circle with d3's front-chain algorithm (packSiblings). It is the default, so pack() and pack(method=circles()) are the same. It takes no options yet. On the wire it is the plain object {"kind": "circles"}.

Each child is packed by its enclosing circle, which depends on its shape.

• A circle is its own enclosing circle.
• An ellipse uses the circle of its larger radius.
• A polygon uses the smallest circle through its vertices.
• A rect or text uses the circle through the corners of its box.
• A nested pack uses the smallest circle around its own children.

Limits

• Children keep the pixel size they are laid out at. The pack does not scale itself to fit the space it is given, and it cannot yet size a child from data. So give each child a size in pixels, e.g., circle(r=12), not circle(r="count"). See #967.
• There is no padding between circles yet.