treemap

Lays children out into a treemap: a 2D tiling of rectangles (or circles) whose areas are proportional to a weight.

GoFish exposes two spellings:

• treemap(...) — an operator for use inside .flow(); it tiles the partitioned data of a chart.
• Treemap(children, ...) — the low-level combinator form: it takes an explicit list of pre-data-bound marks and assigns each one its (x, y, w, h).

The two share the same options below.

from gofish import chart, circle, field, treemap

# treemap(by=..., size=...) partitions the flow's rows itself, mirroring
# spread/group: `by` groups (dropping null genres first), `size` sums
# worldwide gross per group to weight each tile's area.
chart(movies_raw).flow(
    treemap(
        by=field("Major Genre").drop_nulls(),
        size="Worldwide Gross",
        paddingInner=2,
        paddingOuter=2,
        round=True,
    )
).mark(
    circle(fill="Major Genre", stroke="gray", strokeWidth=1).label(
        "Major Genre", position="center", color="white", fontSize=12
    )
).render(w=700, h=420)

Signature

# Operator form (inside .flow())
treemap(**options) -> Operator

# Combinator form (explicit children)
Treemap(children, **options) -> Mark

Parameters

Option	Type	Description
by	str | FieldAccessor	Operator form only (.flow()): field to partition rows by; also accepts a field(...) accessor carrying domain ops (sort/reverse/bin/drop_nulls). Without by, one leaf is emitted per row.
size	str | FieldAccessor | list	Per-leaf weight driving tile area — entry-flagged (one value per split entry): a field name (summed by default), a field(...) accessor, or an explicit per-child list (combinator form).
paddingInner	float	Padding between sibling rectangles.
paddingOuter	float	Padding around the outer edge of the treemap.
round	bool	Round pixel positions/sizes.
tile	"squarify" | "slice" | "dice" | "binary" | "slicedice" | "squarifyCircle"	Tiling strategy ("squarify" default).
sort	"asc" | "desc" | "none"	Sort leaves by weight before layout ("desc" default).
flipY	bool	When True, mirror the layout top-to-bottom inside the treemap box (default False).
leafIntrinsicRadiusField	str	Optional datum key for radius (pixels in treemap space): each leaf is laid out in a square min(leafW, leafH, 2*radius) so the same value can match across separate treemaps.
x, y	float | Value	Optional position offset for the treemap container.
w, h	float | Value	Optional size for the treemap container (the box tiled into). A float is an explicit pixel size; a Value (e.g. a data-driven size channel that sums a field) scales the box through the layout's scale system — and when several treemaps are faceted side by side, they share one scale so their boxes are proportional. When omitted, the treemap fills its slot.

Notes

• A treemap accepts a flat list of children; for multi-level treemaps, compose by nesting Treemap(...) calls (or add a higher-level wrapper).
• In the combinator form, each child is bound to its row with mark.bind_data(d, key); chain .label(accessor, ...) on the mark to show a field's value on each tile. size in combinator form is an explicit list, one weight per child in child order — it does not read back off each child's bound datum.