tiling_pattern.R

library(ggplot2)
library(grid)

size <- unit(70, "points")
x_orig <- unit(0.5, "npc")
y_orig <- unit(0.5, "npc")

gp1 <- gpar(col = "white", fill = "#CEF09D", lwd = 3.3)
gp2 <- gpar(col = "white", fill = "#1C646D", lwd = 3.3)

generate_pattern <- function(angle) {
  angle <- angle %% 180

  # flip when angle is larger than 45
  if (angle <= 45) {
    d <- size / cos(pi * angle / 180)     # distance between two rectangles
    size1 <- size                         # size of main rectangles
    size2 <- size * tan(pi * angle / 180) # size of complement rectangles
  } else {
    d <- size / cos(pi * (90 - angle) / 180)
    size1 <- size / tan(pi * angle / 180)
    size2 <- size
  }
  
  d1 <- d     # distance between main rectangles
  d2 <- d / 2 # distance between complement rectangles
  
  # draw main rectangles
  
  l1 <- purrr::pmap(
    expand.grid(x = -1:1, y = -1:1),
    \(x, y) {
      vp <- viewport(
        x = x_orig + d1 * x,
        y = y_orig + d1 * y,
        width = size1,
        height = size1,
        angle = angle
      )
      
      rectGrob(gp = gp1, vp = vp)
    }
  )

  # draw complement rectangles
  
  l2 <- purrr::pmap(
    expand.grid(x = c(-1L, 1L), y = c(-1L, 1L)),
    \(x, y) {
      vp <- viewport(
        x = x_orig + d2 * x,
        y = y_orig + d2 * y,
        width = size2,
        height = size2,
        angle = angle
      )
      
      rectGrob(gp = gp2, vp = vp)
    }
  )
  
  do.call(grobTree, append(l1, l2))
}

ptn <- generate_pattern(10)
grid.newpage()
grid.draw(ptn)
grid.rect(width = size, height = size, gp = gpar(col = "red", fill = "transparent", alpha = 0.8, lwd = 3))

d <- tempfile()
dir.create(d)
ragg::agg_png(file.path(d, "plot%03d.png"), width = 720, height = 720)

for (i in 0:180) {
  patterns <- lapply(1:4 * (0.25 * i), \(angle) pattern(generate_pattern(angle), width = size, height = size, extend = "repeat"))
  p <- ggplot(mpg, aes(factor(cyl), fill = factor(cyl))) +
    geom_bar() +
    scale_fill_manual(values = patterns) +
    theme_minimal()
  
  plot(p)
}
dev.off()

gifski::gifski(list.files(d, full.names = TRUE), delay = 0.01)