% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/piechart.R
\name{PieChartAtomic}
\alias{PieChartAtomic}
\title{Atomic pie chart (internal)}
\usage{
PieChartAtomic(
  data,
  x,
  y = NULL,
  label = y,
  clockwise = TRUE,
  keep_na = FALSE,
  keep_empty = FALSE,
  theme = "theme_this",
  theme_args = list(),
  palette = "Paired",
  palcolor = NULL,
  palreverse = FALSE,
  alpha = 1,
  facet_by = NULL,
  facet_scales = "free_y",
  facet_ncol = NULL,
  facet_nrow = NULL,
  facet_byrow = TRUE,
  aspect.ratio = 1,
  legend.position = "right",
  legend.direction = "vertical",
  title = NULL,
  subtitle = NULL,
  xlab = NULL,
  ylab = NULL,
  ...
)
}
\arguments{
\item{data}{A data frame.}

\item{x}{A character string specifying the column name for the x-axis
(categories).  Must be character or factor.  Each unique value becomes a
pie slice.}

\item{y}{A character string specifying the numeric column for the y-axis.
When \code{NULL} (default), the count of observations in each
(\code{x}, \code{facet_by}) combination is used and stored as
\code{.y}.}

\item{label}{A character string specifying the column to use for slice
labels.  \code{NULL} (default) hides labels.  When \code{TRUE}, the
\code{y} values are used as labels.  When \code{y = NULL}, use
\code{".y"} to label with the computed counts.}

\item{clockwise}{A logical value.  When \code{TRUE} (default), the pie
slices are ordered clockwise starting from the top.  When \code{FALSE},
slices are ordered counter-clockwise.}

\item{keep_na}{A logical value or a character to replace the NA values in the data.
It can also take a named list to specify different behavior for different columns.
If TRUE or NA, NA values will be replaced with NA.
If FALSE, NA values will be removed from the data before plotting.
If a character string is provided, NA values will be replaced with the provided string.
If a named vector/list is provided, the names should be the column names to apply the behavior to,
and the values should be one of TRUE, FALSE, or a character string.
Without a named vector/list, the behavior applies to categorical/character columns used on the plot,
for example, the \code{x}, \code{group_by}, \code{fill_by}, etc.}

\item{keep_empty}{One of FALSE, TRUE and "level". It can also take a named list to specify
different behavior for different columns. Without a named list, the behavior applies to the
categorical/character columns used on the plot, for example, the \code{x}, \code{group_by}, \code{fill_by}, etc.
\itemize{
\item{\code{FALSE} (default): Drop empty factor levels from the data before plotting.}
\item{\code{TRUE}: Keep empty factor levels and show them as a separate category in the plot.}
\item{\code{"level"}: Keep empty factor levels, but do not show them in the plot.
But they will be assigned colors from the palette to maintain consistency across multiple plots.
Alias: \code{levels}}
}}

\item{theme}{A character string or a theme class (i.e. ggplot2::theme_classic) specifying the theme to use.
Default is "theme_this".}

\item{theme_args}{A list of arguments to pass to the theme function.}

\item{palette}{A character string specifying the palette to use.
A named list or vector can be used to specify the palettes for different \code{split_by} values.}

\item{palcolor}{A character string specifying the color to use in the palette.
A named list can be used to specify the colors for different \code{split_by} values.
If some values are missing, the values from the palette will be used (palcolor will be NULL for those values).}

\item{palreverse}{A logical value indicating whether to reverse the palette. Default is FALSE.}

\item{alpha}{A numeric value specifying the transparency of the plot.}

\item{facet_by}{A character string specifying the column name of the data frame to facet the plot.
Otherwise, the data will be split by \code{split_by} and generate multiple plots
and combine them into one using \code{patchwork::wrap_plots}}

\item{facet_scales}{Whether to scale the axes of facets. Default is "fixed"
Other options are "free", "free_x", "free_y". See \code{ggplot2::facet_wrap}}

\item{facet_ncol}{A numeric value specifying the number of columns in the facet.
When facet_by is a single column and facet_wrap is used.}

\item{facet_nrow}{A numeric value specifying the number of rows in the facet.
When facet_by is a single column and facet_wrap is used.}

\item{facet_byrow}{A logical value indicating whether to fill the plots by row. Default is TRUE.}

\item{aspect.ratio}{A numeric value specifying the aspect ratio of the plot.}

\item{legend.position}{A character string specifying the position of the legend.
if \code{waiver()}, for single groups, the legend will be "none", otherwise "right".}

\item{legend.direction}{A character string specifying the direction of the legend.}

\item{title}{A character string specifying the title of the plot.
A function can be used to generate the title based on the default title.
This is useful when split_by is used and the title needs to be dynamic.}

\item{subtitle}{A character string specifying the subtitle of the plot.}

\item{xlab}{A character string specifying the x-axis label.}

\item{ylab}{A character string specifying the y-axis label.}

\item{...}{Additional arguments.}
}
\value{
A \code{ggplot} object with \code{height} and \code{width}
attributes (in inches) attached.
}
\description{
Core implementation for drawing a single pie chart.  This is the
workhorse behind the exported \code{\link{PieChart}} function — it takes a
\strong{single} data frame (no \code{split_by} support) and returns a
\code{ggplot} object.  The chart maps the proportion of each x-axis
category to the angle of a pie slice using
\code{\link[ggplot2]{coord_polar}()}, with optional faceting and
per-slice labels.
}
\section{Architecture}{

\enumerate{
\item \strong{ggplot dispatch} — selects \code{gglogger::ggplot} or
\code{ggplot2::ggplot} based on
\code{getOption("plotthis.gglogger.enabled")}.
\item \strong{Column resolution} — \code{x} is forced to factor;
\code{y} is validated (numeric, optional).
\item \strong{Count aggregation} — when \code{y = NULL}, the count of
observations per (\code{x}, \code{facet_by}) combination is
computed as a new \code{.y} column.  Factor levels are preserved
after aggregation.
\item \strong{Label resolution} — when \code{label = TRUE}, the label
column is set to \code{y}.  The \code{label} column is then
validated.
\item \strong{Facet column resolution} — \code{facet_by} columns are
validated as factors, allowing up to two columns.
\item \strong{NA / empty-level handling} —
\code{\link{process_keep_na_empty}()} applies \code{keep_na} and
\code{keep_empty} policies.  Per-column \code{keep_empty} settings
are extracted for \code{x} and \code{facet_by}.  When more than one
facet column is provided, their \code{keep_empty} values must be
identical.
\item \strong{Clockwise ordering} — when \code{clockwise = TRUE}
(default), the levels of \code{x} are reversed so that the first
slice starts from the top and proceeds clockwise.  The data is then
sorted by the (possibly reversed) \code{x} factor levels.
\item \strong{Position calculation} — if faceted, grouping by facet
variables; computes cumulative sums (\code{csum}) and label
midpoint positions (\code{pos}) for each slice.
\item \strong{Colour mapping} — \code{\link{palette_this}()} assigns
colours to all \code{x} levels, including \code{NA} (defaulting to
\code{"grey80"}).
\item \strong{Plot assembly} — the \code{ggplot} object is built with
\code{geom_col(width = 1)} and
\code{coord_polar(theta = "y")} to create the circular pie
layout.  The fill scale uses \code{scale_fill_manual()} with
per-slice colours; the \code{drop} argument is controlled by
\code{keep_empty_x}.
\item \strong{Labels} — when \code{label} is not \code{NULL},
\code{\link[ggrepel]{geom_label_repel}()} adds text labels at
the computed midpoint positions (\code{pos}).
\item \strong{Dimension calculation} —
\code{\link{calculate_plot_dimensions}()} computes plot height and
width from \code{aspect.ratio} and legend metrics.  The resulting
\code{height} / \code{width} attributes are stored on the
\code{ggplot} object.
\item \strong{Faceting} — \code{\link{facet_plot}()} wraps the plot
with \code{facet_wrap} / \code{facet_grid} if \code{facet_by} is
provided, respecting the \code{keep_empty} setting for facet
variables.
}
}

\keyword{internal}
