Add a slope

To guide a reader in quantifying the slope of components of an x-y graph, a "slope rose" is helpful. Several radiating lines are drawn, each marked with a numerical slope. A suitable choice of slopes is made automatically, based on the x- and y- scale of the plot.

Usage

add_slope_rose(
  P,
  x = NULL,
  y = NULL,
  scale = 1/4,
  color = "red",
  keepers = c("both", "pos", "neg")
)

add_violin_ruler(
  P,
  x = NULL,
  y = NULL,
  width = 1/10,
  ticks = seq(0, 1, by = 0.1),
  ...
)

Arguments

P: a ggplot2 object made by the ggplot2 or ggformula packages
x: the x-position of the rose. This will be assigned automatically if x isn't specified.
y: the y-position of the rose, just like x.
scale: the size of the rose as a fraction of the plot area covered (default 1/4)
color: text string (e.g. "blue") for the rose
keepers: whether to show "both" positive and negative slopes or just show the "pos" or the "neg"
width: for rulers, the distance between tick marks (in native units, where categories are separated by a distance of 1.)
ticks: Integers, typically 0:5, that label the ticks.
...: additional graphical parameters, e.g. color = "blue"

Value

A ggplot graphics object

Details

For the ruler, x gives the position of the root of the ruler, with the rest of the ruler moving off to the left. (For vertically oriented rulers, use a negative width.)

Note

Use the pipe operator to send a previously made plot to have a rose added. Don't use the {ggplot2} + connector.

Examples

mtcars |> point_plot(mpg ~ hp, annot="model") |> add_slope_rose()

mtcars |> point_plot(wt ~ hp) |> add_slope_rose(keepers="pos", color="blue", x=100, scale=.5 )