R/geom-violin.R

In ggpattern: 'ggplot2' Pattern Geoms

#' @rdname geom-docs
#' @export
geom_violin_pattern <- function(mapping = NULL, data = NULL,
                                stat = "ydensity", position = "dodge",
                                ...,
                                draw_quantiles = NULL,
                                trim = TRUE,
                                bounds = c(-Inf, Inf),
                                scale = "area",
                                na.rm = FALSE,
                                orientation = NA,
                                show.legend = NA,
                                inherit.aes = TRUE) {
  layer(
    data = data,
    mapping = mapping,
    stat = stat,
    geom = GeomViolinPattern,
    position = position,
    show.legend = show.legend,
    inherit.aes = inherit.aes,
    params = list2(
      trim = trim,
      scale = scale,
      draw_quantiles = draw_quantiles,
      na.rm = na.rm,
      orientation = orientation,
      bounds = bounds,
      ...
    )
  )
}

#' @rdname ggpattern-ggproto
#' @format NULL
#' @usage NULL
#' @export
GeomViolinPattern <- ggproto("GeomViolinPattern", GeomViolin,

  draw_group = function(self, data, ..., draw_quantiles = NULL, flipped_aes = FALSE) {
    data <- flip_data(data, flipped_aes)
    # Find the points for the line to go all the way around
    data <- transform(data,
                      xminv = x - violinwidth * (x - xmin),
                      xmaxv = x + violinwidth * (xmax - x)
    )

    # Make sure it's sorted properly to draw the outline
    newdata <- vec_rbind(
      transform(data, x = xminv)[order(data$y), ],
      transform(data, x = xmaxv)[order(data$y, decreasing = TRUE), ]
    )

    # Close the polygon: set first and last point the same
    # Needed for coord_polar and such
    newdata <- vec_rbind(newdata, newdata[1,])
    newdata <- flip_data(newdata, flipped_aes)

    # Draw quantiles if requested, so long as there is non-zero y range
    if (length(draw_quantiles) > 0 & !scales::zero_range(range(data$y))) {
      if (!(all(draw_quantiles >= 0) && all(draw_quantiles <= 1))) {
        cli::cli_abort("{.arg draw_quantiles} must be between 0 and 1.")
      }

      # Compute the quantile segments and combine with existing aesthetics
      quantiles <- create_quantile_segment_frame(data, draw_quantiles)
      aesthetics <- data[
        rep(1, nrow(quantiles)),
        setdiff(names(data), c("x", "y", "group")),
        drop = FALSE
      ]
      aesthetics$alpha <- rep(1, nrow(quantiles))
      both <- vec_cbind(quantiles, aesthetics)
      both <- both[!is.na(both$group), , drop = FALSE]
      both <- flip_data(both, flipped_aes)
      quantile_grob <- if (nrow(both) == 0) {
        zeroGrob()
      } else {
        GeomPath$draw_panel(both, ...)
      }

      ggname("geom_violin_pattern", grobTree(
        GeomPolygonPattern$draw_panel(newdata, ...),
        quantile_grob)
      )
    } else {
      ggname("geom_violin_pattern", GeomPolygonPattern$draw_panel(newdata, ...))
    }
  },

  draw_key = function(self, ...) draw_key_polygon_pattern(...),

  default_aes = defaults(
    aes(weight = 1, colour = "grey20", fill = "white", linewidth = 0.5,
      alpha = NA, linetype = "solid"),
    pattern_aesthetics
  ),

  rename_size = TRUE
)