Contemplating the meaning of life

420_phyllotaxis.R

# Based on https://chichacha.netlify.com/2019/01/29/playing-around-with-phyllotactic-spirals/

library(tidyverse) ## for pretty much everything...

phi <- (1 + sqrt(5)) / 2 
golden_angle <- pi*(3-sqrt(5))

create_art <- function(n=1800,u=5,v=0,angle=golden_angle,colors="#ffffff",...){
  
  my_colours <- colors ## default is using one colour, white, but I can use vector of colours too. 
  
  ## Create data frame first using those parameters specified above
  df <- tibble(
    idx = c(0:(n-1)), ## you can increase the number here to use more lines.
    t = seq(0,2*pi,length.out=n),  ## since I used 0 to 1800 above, need to add 1
    r = sqrt(idx), ## radius   
    x = r*cos(angle*idx),
    y = r*sin(angle*idx),
    color_angle = atan2(y=y,x=x) ## get angle between x-axos and the vector from the origin to x,y
  )
  
  ## In case you specified m2>m then change 
  v <- ifelse(v<u,v,v%%u)
  max_r <- max(df$r)*1.1
  
  my_art <- df %>% 
    ggplot(aes(x=x,y=y,color=color_angle)) +
    geom_point(data= . %>% filter(idx%%u==v), ## Changed from geom_path
              aes(size=idx, alpha=idx)) + 
    coord_fixed() +
    theme_void() +
    scale_alpha_continuous(guide="none", range=c(0,1), trans="sqrt")+ 
    scale_size_continuous(guide="none",  range=c(10,0), trans="sqrt") +
    scale_color_gradientn(guide="none", 
                          colors=my_colours) +
    theme(panel.background = element_rect(fill="#000000")) +
    expand_limits(x=c(-max_r,max_r),y=c(-max_r,max_r)) 
  
  my_art + annotate(geom="text", x=Inf,y=-Inf,
                    label=str_glue('n: {n} | u: {u} | v: {v} | angle: {round(angle,3)} radian'),
                    hjust=1,vjust=-1)
}

p1_colors <- viridis::viridis_pal(alpha = 0.5, begin = 1, end = 0, option = "magma")(20)
p2_colors <- viridis::viridis_pal(alpha = 0.5, option = "viridis")(20)

p1 <- create_art(n=420, angle = 1-cos(42), colors = p1_colors)
p2 <- create_art(n=4200, angle = 1+sin(4.2), colors = p2_colors) +
  theme(panel.background = element_blank())

p1 + annotation_custom(grob = ggplotGrob(p2))