Binary Packing

deckgl_marimo.pack_binary

pack_binary(n, attributes, start_indices=None)

Pack layer data into an aligned binary buffer for deck.gl.

Parameters:

Name	Type	Description	Default
n	int	Number of data items (rows/features).	required
attributes	dict[str, tuple[Any, str, int]]	Mapping of attribute name to (array, dtype, size) where: - array: numpy array (flat, raveled) - dtype: numpy dtype string ("float32", "uint8", etc.) - size: components per element (e.g. 2 for [lon, lat], 4 for RGBA)	required
start_indices	Any | None	Optional uint32 array for variable-length data (polygons, paths).	None

Returns:

Type	Description
tuple[dict, bytes]	(metadata, buffer) ready for the JS applyBinaryData() function.

deckgl_marimo.pack_polygon_binary

pack_polygon_binary(data, get_polygon='polygon', get_fill_color=None, per_polygon_colors=None)

Pack polygon data into a binary buffer for deck.gl.

Convenience wrapper around :func:pack_binary for polygon data.

Parameters:

Name	Type	Description	Default
data	list[dict] | Any	List of dicts, or a dict with pre-built numpy arrays:: {"polygon_coords": np.ndarray, # (total_verts, 2) float32 "start_indices": np.ndarray, # (n_polygons,) uint32 "colors": np.ndarray | None} # (total_verts, 4) uint8	required
get_polygon	str	Key in each dict for the polygon coordinates.	'polygon'
get_fill_color	Any	If a string, key for per-polygon [r, g, b, a] color.	None
per_polygon_colors	Any | None	Pre-resolved per-polygon RGBA colors as a (n_polygons, 4) uint8 array (e.g. from a ColorScale or callable accessor). Expanded to per-vertex colors here. Ignored on the pre-built-arrays fast path and when get_fill_color is a column name.	None

Returns:

Type	Description
tuple[dict, bytes]