layer_key ¶

Describe a layer's entry in a manual legend (manual_key= of any geom).

The key is drawn by the layer's geom with its constant aesthetics, then the values given here. Layers with the same group share a legend; a label used by several layers of one group becomes one key drawing all of them. The key shows even when the layer has show_legend=False.

Parameters:

• label (str) –

  Text next to the key.

• group (str, default: "manual" ) –

  Legend the key joins. The "manual" legend has no title; give one with labs(manual="Title") or guides(manual=guide_legend("Title")). Other groups are titled by their name unless guides(<group>=...) sets one.

• index (int, default: None ) –

  Position of the key in its legend; keys with an index come first, in index order, then the others in layer order.

• **kwargs (Any) –

  Aesthetic values for the key only, e.g. size=3 or shape=21.

Returns:

• FeatureSpec –

  The key specification, for a geom's manual_key.

Raises:

• TypeError –

  When label is not a string.

Examples:

>>> from ggrust import *
>>> data = {"day": [1, 2, 3, 4, 5], "steps": [6.1, 8.4, 7.2, 9.9, 8.8]}
>>> plot = (
...     ggplot(data, aes("day", "steps"))
...     + geom_line(color="grey", manual_key=layer_key("trend", linetype="solid"))
...     + geom_point(color="firebrick", size=4, manual_key=layer_key("measured"))
...     + labs(manual="Steps (thousands)")
... )