add_slope_rose {LSTbook}

Add a slope "rose" to a plot.

Description

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"

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.)

Value

A ggplot graphics object

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 )