Neon Ghosts with ggplot2

Neon Ghosts with ggplot2 Dr. Mowinckel 2025-10-31 Ever wanted to make a haunted house in R? Here’s a quick and fun way to conjure up a whole gang of neon ghosts using ggplot2. Each ghost is a little different — some tall, some stout, all a bit wobbly—thanks to a shape generator that randomizes their size and wiggle. The plotting function layers up neon glows for the outline, eyes, and mouth, then adds a faint fill and solid black features for that classic ghostly look. Try running it a few times to see what kind of spectral friends you get! library(ggplot2) library(scales) #' Ghost plotting function #' @param ghost_df Data frame with x and y coordinates of the ghost shape #' @param ghost_color Color of the ghost (default is neon green) #' @return ggplot object of the ghost plot_simple_ghost <- function(ghost_df, ghost_color = "#39FF14") { x_center <- mean(range(ghost_df$x)) y_top <- max(ghost_df$y) y_bottom <- min(ghost_df$y) ghost_height <- y_top -y_bottom ghost_width <- diff(range(ghost_df$x)) # Eyes eye_y <- y_bottom +0.7 *ghost_height eye_x <- x_center +c(-0.06,0.06)*ghost_width eyes <- data.frame(x = eye_x, y = rep(eye_y, 2)) # Mouth: several waves mouth_width <- ghost_width *0.4 mouth_x <- seq(x_center -0.3 *mouth_width, x_center +0.3 *mouth_width, length.out = 80) mouth_y <- y_bottom +0.55 *ghost_height +sin(seq(0,7*pi, length.out = 80)) *0.04 *ghost_height 1 mouth <- data.frame(x = mouth_x, y = mouth_y) # 8 neon glow layers glow_layers <- data.frame( linewidth = c(12,10,8,6,4.5,3,2,1), alpha = c(0.04,0.06,0.09,0.13,0.18,0.25,0.35,0.5) ) p <- ggplot() + geom_polygon( data = ghost_df, aes(x, y), fill = ghost_color, alpha = 0.15,color = NA ) # Glow layers for outline, eyes, and mouth for(i in seq_len(nrow(glow_layers))) { p <- p + geom_polygon( data = ghost_df, aes(x, y), fill = NA,color = scales::alpha(ghost_color, glow_layers$alpha[i]), linewidth = glow_layers$linewidth[i] )+ geom_point( data = eyes, aes(x, y), color = scales::alpha(ghost_color, glow_layers$alpha[i]), size = glow_layers$linewidth[i] *1.1 )+ geom_path( data = mouth, aes(x, y), color = scales::alpha(ghost_color, glow_layers$alpha[i]), linewidth = glow_layers$linewidth[i] ) } # Solid black mouth and eyes p <- p + geom_path( data = mouth, aes(x, y), color = "black",linewidth = 1.2 )+ geom_point( data = eyes, aes(x, y), 2 color = "black", size = 1.2 ) # Fix aspect ratio and theme p+ coord_fixed( xlim = c(-4,4), ylim = c(-3,8), expand = TRUE )+ theme_void() + theme( plot.background = element_rect(fill = "black",color = NA), panel.background = element_rect(fill = "black",color = NA) ) } #' Generate a random ghost shape #' @param seed Optional seed for reproducibility #' @return Data frame with x and y coordinates of the ghost shape ghost_shape <- function(seed = NULL) { if (!is.null(seed)) set.seed(seed) width <- sample(seq(0.5,3,length.out = 6), 1) height <- sample(1:6,1) x <- seq(-1,1,length.out = 100)*width amp <- runif(1,0.15,0.28) freq <- sample(3:7,1) phase <- runif(1,0,2*pi) y_top <- sqrt(1-(x/width)^2)*height +runif(1,-0.03,0.03) y_bottom <- -0.5 *height +sin(seq(0, freq *pi, length.out = 100)+phase) *amp *height data.frame( x = c(x, rev(x)), y = c(y_top, rev(y_bottom)) ) } ghost_shape() |> plot_simple_ghost(ghost_color = "#39FF14") ghost_shape() |> plot_simple_ghost(ghost_color = "#FF6EC7") 3 ghost_shape() |> plot_simple_ghost(ghost_color = "#1E90FF") 4