isoband_lgbt.R

library(isoband)
library(magick)
library(sf)
library(tidyverse)

# Adapted from Claus Wilke's code
# https://github.com/clauswilke/isoband
sf_from_image <- function(image, nbands) {
  image_gray <- image %>% image_quantize(colorspace = "gray")
  image_raster <- as.raster(image_gray)
  d <- dim(image_raster)
  m <- matrix(c((255-col2rgb(image_raster)[1,])), 
              nrow = d[1], ncol = d[2], byrow = TRUE)
  b <- isobands(1:d[2], d[1]:1, m, 20*(0:(nbands-1)), 20*(1:nbands))
  bands <- iso_to_sfg(b)
  data <- st_sf(
    level = letters[1:length(bands)],
    geometry = st_sfc(bands)
  )
}


# create an sf object with isoband
image_sf <- "danielle.jpg" %>%
  image_read() %>%
  image_resize(geometry = "200x200") %>%
  sf_from_image(nbands = 7)

# specify a rainbow palette
lgbt <- c(
  `a` = "#FFEF00", # Canary Yellow 
  `b` = "#FF8C00", # Dark Orange 
  `c` = "#E70000", # Electric Red 
  `d` = "#00811F", # La Salle Green 
  `e` = "#0044FF", # Blue (RYB) 
  `f` = "#760089", # Patriarch 
  `g` = "#333333"  # Grey (highlight)
)

# draw image
pic <- image_sf %>%
  ggplot(aes(fill = level, color = level)) +
  geom_sf(size = 0.1, show.legend = FALSE) +
  scale_color_manual(values = lgbt) +
  scale_fill_manual(values = lgbt) +
  coord_sf(expand = FALSE) + 
  theme_void() + 
  theme(panel.background = element_rect(fill="black"))

plot(pic)
ggsave("C:/Users/Dan/Desktop/danielle_lgbt.png", width = 5, height = 5)