Nearest intersection between a shape and a segment specified with an angle

Take a shape, and segment starting on the centroid and having a particular angle, which point is the nearest where the segment intersects with the shape?

Usage

coo_intersect_angle(coo, angle = 0)

coo_intersect_direction(coo, direction = c("down", "left", "up", "right")[4])

# S3 method for default
coo_intersect_direction(coo, direction = c("down", "left", "up", "right")[4])

# S3 method for Coo
coo_intersect_direction(coo, direction = c("down", "left", "up", "right")[4])

Arguments

coo

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

angle

numeric an angle in radians (0 by default).

direction

character one of "down", "left", "up", "right" ("right" by default)

Value

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

Note

shapes are always centered before this operation. If you need a simple direction such as (down, left, up, right)ward, then use coo_intersect_direction which does not need to find an intersection but relies on coordinates and is about 1000.

See also

Other coo_ intersect: coo_intersect_segment()

Examples

coo <- bot[1] %>% coo_center %>% coo_scale
coo_plot(coo)
coo %>% coo_intersect_angle(pi/7) %>%
   coo[., , drop=FALSE] %>% points(col="red")


 # many angles
 coo_plot(coo)
 sapply(seq(0, pi, pi/12),
       function(x) coo %>% coo_intersect_angle(x)) -> ids
 coo[ids, ] %>% points(col="blue")

 coo %>%
 coo_intersect_direction("down") %>%
 coo[.,, drop=FALSE] %>% points(col="orange")