% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/plot_allviz.R
\name{.prep_spec}
\alias{.prep_spec}
\title{Prepare Spectral Data for Plotting}
\usage{
.prep_spec(x, ppm, shift)
}
\arguments{
\item{x}{Numeric vector or matrix of spectra.}

\item{ppm}{Numeric chemical shift vector.}

\item{shift}{Length-2 numeric vector specifying ppm window.}
}
\value{
A list with elements:
\describe{
\item{ppm}{Subsetted chemical shift axis}
\item{X}{Matrix of subsetted spectra}
}
}
\description{
Internal helper that validates input, enforces ppm ordering,
subsets the selected shift region, and returns matrix-form data.
}
\keyword{internal}
