R/riso_circles.R

In nrennie/aRt: Generative Art with R

#' Riso Circles
#'
#' This function generates a coloured generative art ggplot object using
#' overlapping semi-transparent circles.
#'
#' @param n_x Number of columns in grid. Default 4.
#' @param n_y Number of rows in grid. Default 4.
#' @param n_circles Number of circles per grid square. Default 2.
#' @param r Radius of circles. Default 0.5.
#' @param jitter_x Jitter in x direction for circle positions. Default 0.25.
#' @param jitter_y Jitter in y direction for circle positions. Default 0.3.
#' @param alpha Transparency of circles. Default 0.5.
#' @param col_palette Vector of colours. Default `c("#6497b1", "#6a359c", "#FFB04F", "#679c35", "#cd1076")`.
#' @param circle_bg Background colour of circles. Default `"#fafafa"`.
#' @param bg_col Background colour. Default `"gray10"`.
#' @param interpolate Boolean indicating if colours should be interpolated. Default `TRUE`.
#' @param s Seed value. Default 1234.
#' @return A ggplot object.
#' @examples
#' riso_circles()
#' @export

riso_circles <- function(n_x = 4,
                         n_y = 4,
                         n_circles = 2,
                         r = 0.5,
                         jitter_x = 0.25,
                         jitter_y = 0.3,
                         alpha = 0.5,
                         col_palette = c("#6497b1", "#6a359c", "#FFB04F", "#679c35", "#cd1076"),
                         circle_bg = "#fafafa",
                         bg_col = "gray10",
                         interpolate = TRUE,
                         s = 1234) {
  plot_data <- withr::with_seed(
    seed = s,
    code = {
      plot_data <- data.frame(
        x0 = stats::runif(n_x * n_y * n_circles, -1 * jitter_x, jitter_x),
        y0 = stats::runif(n_x * n_y * n_circles, -1 * jitter_y, jitter_y),
        r = rep(r, n_x * n_y * n_circles),
        grp = as.character(rep(seq_len(n_x * n_y), each = n_circles))
      )
      if (interpolate) {
        plot_data$cols <- sample(
          grDevices::colorRampPalette(col_palette)(n_x * n_y * n_circles)
        )
      } else {
        plot_data$cols <- sample(
          col_palette,
          size = n_x * n_y * n_circles, replace = TRUE
        )
      }
      plot_data
    }
  )
  g <- ggplot2::ggplot(data = plot_data) +
    ggforce::geom_circle(
      mapping = ggplot2::aes(
        x0 = .data$x0, y0 = .data$y0, r = .data$r
      ),
      fill = circle_bg,
      colour = "transparent"
    ) +
    ggforce::geom_circle(
      mapping = ggplot2::aes(
        x0 = .data$x0, y0 = .data$y0,
        r = .data$r, fill = .data$cols
      ),
      colour = "transparent",
      alpha = alpha
    ) +
    ggplot2::facet_wrap(~grp, ncol = n_x, nrow = n_y) +
    ggplot2::scale_fill_identity() +
    ggplot2::coord_fixed() +
    theme_aRt(bg_col, 0.5)
  return(g)
}