% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/render_alpha_outline.R
\name{find_border_alpha_gaps}
\alias{find_border_alpha_gaps}
\title{Find Border Alpha Gaps}
\usage{
find_border_alpha_gaps(alpha, alpha_threshold = 0.25)
}
\arguments{
\item{alpha}{Numeric alpha matrix.}

\item{alpha_threshold}{Default \code{0.25}. Pixels below this alpha are considered
low-alpha gap pixels.}
}
\value{
Logical matrix marking low-alpha pixels connected to the image
exterior.
}
\description{
Internal helper that classifies which low-alpha pixels are part
of the exterior border region. Pixels below \code{alpha_threshold} are considered
low alpha. The algorithm starts from low-alpha pixels on the image boundary
and performs an 8-connected flood fill through other low-alpha pixels.
Low-alpha regions enclosed by pixels at or above \code{alpha_threshold} are not
reached, so they are protected from \code{fill_alpha_gaps()}.
}
\keyword{internal}
