ferrum.layer¶

Layer descriptor for multi-mark charts.

Internal layer wrapper used by composite-mark expansion.

Layer ¶

Single rendering layer inside a multi-layer Chart.

Most multi-layer charts are built via the + operator on two Chart instances (chart1 + chart2). Direct construction of Layer objects is rarely needed outside of ferrum internals and composite-mark expansion code.

Parameters:

Name	Type	Description	Default
`data`	`object`	DataFrame or Arrow-compatible object for this layer. When `None` the layer inherits data from the parent `ChartSpec`.	`None`
`mark`	`str or MarkSpec`	Mark type string (e.g. `"point"`, `"line"`) or a `MarkSpec` object.	`None`
`encoding`	`dict`	Mapping of channel names to `ChannelBase` objects. Defaults to an empty dict when omitted.	`None`
`transforms`	`list`	Sequence of transform objects applied to this layer's data before rendering. Defaults to an empty list when omitted.	`None`
`mark_kwargs`	`dict`	Extra keyword arguments forwarded to the mark renderer (e.g. `{"dx": 5, "opacity": 0.7}`).	`None`

Examples:

>>> from ferrum.layer import Layer
>>> layer = Layer(mark="text", encoding={"x": "x", "y": "y"}, mark_kwargs={"dx": 5})