intercross.point: Find a intercross point between two lines

In liuguofang/figsci: Let plotting figure and scientific visualization and information gain easier and more efficient.

Find a intercross point between two lines

Description

Find a intercross points between two lines (AB, CD).

Usage

intercross.point(x1, y1, x2, y2, x3, y3, x4, y4) 

Arguments

x1

the x value of point A.

y1

the y value of point A.

x2

the x value of point B.

y2

the y value of point B.

x3

the x value of point C.

y3

the y value of point C.

x4

the x value of point D.

y4

the y value of point D.

Examples

d <- data.frame(x = c(2, 5, 3, 8), y = c(8, 3, 2, 7))
with(d, plot(x, y, ylim = c(0, 8)))
segments(d$x[1], d$y[1], d$x[2], d$y[2])
segments(d$x[3], d$y[3], d$x[4], d$y[4])
#p is the point of intersection
p <- intercross.point(2, 8, 5, 3, 3, 2, 8, 7)
points(p[1], p[2], col = 2)
polygon(c(d$x[1], d$x[3], p[1]), c(d$y[1], d$y[3], p[2]), col = 2)
polygon(c(d$x[2], d$x[4], p[1]), c(d$y[2], d$y[4], p[2]), col = 3)

liuguofang/figsci documentation built on Nov. 24, 2023, 1:45 p.m.