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Validate Termination Position

validate_termination_position.Rd

Checks if a position is valid for termination (has at least one black neighbor or is the initial center pixel). Used in async mode to prevent isolated pixels when workers operate on stale grid snapshots.

Usage

validate_termination_position(pos, grid, neighborhood = "4-hood")

Arguments

pos

Integer vector of length 2 (row, col). Position to validate.

grid

Numeric matrix. Current grid state.

neighborhood

Character. "4-hood" or "8-hood". Default "4-hood".

Value

Logical. TRUE if position is valid for termination, FALSE otherwise.

Details

A termination position is valid if:

  1. The position itself is already black (touching black), OR

  2. The position has at least one black neighbor

This prevents the creation of isolated black pixels in async mode where workers may have stale grid snapshots.

See also

validate_no_isolated_pixels

Examples

grid <- initialize_grid(10)
#> INFO [2026-02-03 16:36:10] Initializing grid of size 10x10
# Center (5,5) is black, so (5,6) has a black neighbor
validate_termination_position(c(5, 6), grid, "4-hood")  # TRUE
#> [1] TRUE
# Position (1,1) is far from center - no black neighbors
validate_termination_position(c(1, 1), grid, "4-hood")  # FALSE
#> [1] FALSE