Get outline direction sign

Determine if an outline is traced counter-clockwise (positive/trigonometric) or clockwise (negative).

Usage

get_direction_sign(x, ..., .cols = NULL)

Arguments

x

A matrix (nx2), list of matrices, or tibble with coo columns.

...

Additional arguments (reserved for future use).

.cols

Column name(s) to process when x is a tibble. If NULL, automatically detects columns containing coo objects.

Value

• If x is a single matrix: returns a logical (TRUE = counter-clockwise)

• If x is a list: returns a logical vector

• If x is a tibble: returns a logical vector extracted from coo column

Details

Uses the signed area formula (shoelace). Positive area indicates counter-clockwise (trigonometric) direction, negative indicates clockwise.

Returns TRUE for counter-clockwise, FALSE for clockwise.

See also

coo_direction_positive(), coo_direction_negative()

Examples

get_direction_sign(shapes$cat)
#> [1] FALSE
get_direction_sign(shapes)
#> $cat
#> [1] FALSE
#> 
#> $dog
#> [1] FALSE
#> 
#> $heart
#> [1] FALSE
#> 
#> $leaf2
#> [1] FALSE
#>