R/bricks.R

In nrennie/aRt: Generative Art with R

#' Brick size
#'
#' This function generates a vector of length n which adds to 100.
#'
#' @param n Length of vector to output.
#' @return A factor vector of length n, containing bricks sizes.
#' @noRd

brick_size <- function(n) {
  size <- 100
  r <- sample(1:n)
  o1 <- size * (r / sum(r))
  output <- round(o1)
  if (sum(output) < size) {
    output[1] <- output[1] + (size - sum(output))
  }
  if (sum(output) > size) {
    output[1] <- output[1] - (size - sum(output))
  }
  return(output)
}


#' Bricks
#'
#' This function generates a coloured generative art ggplot object using polygons.
#'
#' @param n_y Number of rows. Default 20.
#' @param colours Vector of colours. Can be any length. Default c("#9B1D20", "#3D2B3D", "#CBEFB6", "#635D5C").
#' @param bg_col Background colour. Default "gray97".
#' @param s Seed value. Default 1234.
#' @return A ggplot object.
#' @examples
#' bricks()
#' @export

bricks <- function(n_y = 20,
                   colours = c("#9B1D20", "#3D2B3D", "#CBEFB6", "#635D5C"),
                   bg_col = "gray97",
                   s = 1234) {
  plot_data <- withr::with_seed(
    seed = s,
    code = {
      n_y <- round(n_y)
      total_bricks <- 0
      plot_data <- data.frame(
        id = c(),
        cols = c(),
        x = c(),
        y = c()
      )
      for (i in 1:n_y) {
        num_bricks <- sample(2:8, size = 1)
        bs <- brick_size(num_bricks)
        x1 <- c(0, cumsum(bs)[1:(num_bricks - 1)]) + 0.25
        x2 <- c(cumsum(bs)[1:(num_bricks - 1)], 100) - 0.25
        x3 <- c(cumsum(bs)[1:(num_bricks - 1)], 100) - 0.25
        x4 <- c(0, cumsum(bs)[1:(num_bricks - 1)]) + 0.25
        y1 <- rep(5 * i + 0.1, num_bricks)
        y2 <- rep(5 * i + 0.1, num_bricks)
        y3 <- rep(5 * i + 4.9, num_bricks)
        y4 <- rep(5 * i + 4.9, num_bricks)
        x <- c(matrix(c(x1, x2, x3, x4), byrow = TRUE, nrow = 4, ncol = length(x1)))
        y <- c(matrix(c(y1, y2, y4, y3), byrow = TRUE, nrow = 4, ncol = length(y1)))
        id <- rep((total_bricks + 1):(total_bricks + num_bricks), each = 4)
        total_bricks <- total_bricks + num_bricks
        positions <- data.frame(x = x, y = y, id = id)
        values <- data.frame(
          id = unique(id),
          cols = n_col_select(
            n = length(colours),
            size = num_bricks,
            random = TRUE,
            s = s
          )
        )
        datapoly <- merge(values, positions, by = c("id"))
        plot_data <- rbind(plot_data, datapoly)
      }
      plot_data
    }
  )

  p <- ggplot2::ggplot(
    data = plot_data,
    mapping = ggplot2::aes(x = .data$x, y = .data$y)
  ) +
    ggplot2::geom_polygon(
      mapping = ggplot2::aes(group = .data$id, fill = .data$cols),
      colour = NA
    ) +
    ggplot2::scale_fill_manual(values = colours) +
    theme_aRt(bg_col)
  return(p)
}