Nearest intersection between a shape and a segment

Take a shape, and an intersecting segment, which point is the nearest of where the segment intersects with the shape? Most of the time, centering before makes more sense.

Usage

coo_intersect_segment(coo, seg, center = TRUE)

Arguments

coo

matrix of (x; y) coordinates or any Coo object.

seg

a 2x2 matrix defining the starting and ending points; or a list or a numeric of length 4.

center

logical whether to center the shape (TRUE by default)

Value

numeric the id of the nearest point, a list for Coo. See examples.

See also

Other coo_ intersect: coo_intersect_angle()

Examples

coo <- bot[1] %>% coo_center %>% coo_scale
seg <- c(0, 0, 2, 2) # passed as a numeric of length(4)
coo_plot(coo)
segments(seg[1], seg[2], seg[3], seg[4])
coo %>% coo_intersect_segment(seg) %T>% print %>%
# prints on the console and draw it
   coo[., , drop=FALSE] %>% points(col="red")

#> [1] 79

# on Coo
bot %>%
    slice(1:3) %>% # for the sake of speed
    coo_center %>%
    coo_intersect_segment(matrix(c(0, 0, 1000, 1000), ncol=2, byrow=TRUE))
#> $brahma
#> [1] 79
#> 
#> $caney
#> [1] 96
#> 
#> $chimay
#> [1] 110
#>