Get pixel colours from an image using R and ImageMagick

get_pixels.R

# Create a pixel chart of a picture, inspired by https://blog.datawrapper.de/weekly-chart-data-art-scatterplot-with-a-pearl-earring/
# My workflow:
# Open an image in GIMP, scale to desired size and change Mode to Indexed with max number of colours.
# Run following R code to get coordinates and RGB. (Alternatively could use imagemagick in command line and eg sed/awk.)
# Load CSV into Datawrapper; manually set colours (if few enough) or use API.

library(magrittr)
library(magick)
library(readr)
library(stringr)
library(dplyr)

test <- image_read("68_index80.png")

image_convert(test, "txt") %>% image_write("test.txt")

pixels <- 
  read_table("pixels.txt", col_names = F, skip = 1) %>% 
  set_names("source") %>% 
  mutate(
    x = source %>% str_extract("^[0-9]+"),
    y = source %>% str_extract(",[0-9]+") %>% str_replace(",", ""),
    hex = source %>% str_extract("#[0-9A-F]+")
  ) %>% 
  select(-source)
write_csv(pixels, "pixels.csv")

Should that be
read_table ('test.txt, col_names = F, skip = 1) %>%
?

Yes, "test.txt" - I think I tried to change my code to be a bit more generic but obviously didn't run it for a sanity check. 🤦🏻‍♂️