sunshinexy {plothelper}

Generating Lines Which Link One Points to Many

Description

Suppose there is a middle point a, this function simultaneous generates points on lines that start from a to other points.

Usage

sunshinexy(
  x = 0,
  y = 0,
  outer = data.frame(1, 1),
  n = 10,
  delete_n = 0,
  distance = FALSE,
  checks = TRUE
)

Arguments

x

the x coordinate of the middle points. It should be of length 1.

y

the y coordinate of the middle points. It should be of length 1.

outer

the other points. It can be a data frame, It must have exactly 2 columns and must be numeric without NA.

n

default is 10. The number of points per line.

delete_n

default is 0. The number of points to be deleted. Suppose a line has p1, p2, p3, p4, p5 points on it with p1 as the starting point. if delete_n is 2, then p1 and p2 will be deleted. Note: n - delete_n must be larger than 1.

distance

default is FALSE. If it is TRUE, a column named "distance" is added which indicates the distances from the middle point to other points.

checks

default is TRUE. It indicates whether to check input validity. Do not turn it off unless you are sure that the input is OK.

Value

A data frame that has 3 columns. The first and second columns are named "x" and "y", the third column is named "g" indicating group numbers. If distance = TRUE, a fourth column is added which indicates the distances from the middle point to other points.

Examples

library(ggplot2)
p=c(1, 1, 0, -1, -1, -1, 0, 1)
q=c(0, 1, 1, 1, 0, -1, -1, -1)
pq=data.frame(cbind(p, q))
dat=sunshinexy(outer=pq, n=20, delete_n=5, distance=TRUE)
ggplot()+coord_fixed()+theme_void()+
	geom_point(data=pq, aes(p, q), size=4)+
	geom_line(show.legend=FALSE, data=dat, aes(x, y, group=g, color=distance), size=2)+
	scale_color_continuous(low="blue", high="red")