Processing images for memory experiments

make_grid.R

# make the grid file

grid_size <- 900
n_square <- 6
ss <- 900 / n_square # square size

d <- array(0, c(grid_size, grid_size, 4))
fillcolor <- c(235, 220, 36, 128)

for (i in 1:n_square) {
  for (j in 1:n_square) {
    if ((i + j) %% 2 == 0) {
      d[((i - 1) * ss + 1):(i * ss), ((j - 1) * ss + 1):(j * ss), 1] <- 
        fillcolor[1]
      d[((i - 1) * ss + 1):(i * ss), ((j - 1) * ss + 1):(j * ss), 2] <- 
        fillcolor[2]
      d[((i - 1) * ss + 1):(i * ss), ((j - 1) * ss + 1):(j * ss), 3] <- 
        fillcolor[3]
      d[((i - 1) * ss + 1):(i * ss), ((j - 1) * ss + 1):(j * ss), 4] <- 
        fillcolor[4]
      
    }
  }
}

png::writePNG(d / 255, here::here("grid.png"))

process.R

library(magick)

# Image processing pipeline ------------------------------------------
# 0) We start with images we want to process
# 1) Manually, in GIMP we crop them to square format
#    => we save the result in `square-hires` folder 
#    with suffix `-cut`
# 2) The following script resizes the images and overlays a grid 
#    => results saved to `900px` folder
#     with suffix `-cut-900x900` and `-cut-900x900x` (for grid version)
#
# We use magick package
#   https://cran.r-project.org/web/packages/magick/vignettes/intro.html#Transformations

# SETUP: folders and files -------------------------------------------

path_to_square_hires <- here::here("square-hires")
path_to_900px        <- here::here("900px")
fn_grid              <- here::here("grid.png")

# tool for renaming/suffixes -----------------------------------------
fname <- function(fn, folder, suffix = "") {
  name_wo_ext <- tools::file_path_sans_ext(fn)
  ext <- tools::file_ext(fn)
  file.path(folder, paste0(name_wo_ext, suffix, ".", ext))
}

# load the grid ------------------------------------------------------
img_grid <- image_read(fn_grid)
img_grid_900px <- image_resize(img_grid, "900x900")

# list files to process and process one at the time ------------------
files <- dir(path = path_to_square_hires)
for (fn in files) {
  # read
  img <- image_read(fname(fn, path_to_square_hires))
  # resize
  img_900px <- image_resize(img, "900x900")
  # add grid
  img_x <- c(img_900px, img_grid_900px) # try image_info(img_x) 
  img_f <- image_mosaic(img_x)
  # save both
  image_write(img_900px, path = fname(fn, path_to_900px, "-900x900"),
              format = "jpeg", quality = 95)
  image_write(img_f, path = fname(fn, path_to_900px, "-900x900x"),
              format = "jpeg", quality = 90)
}

# notes ------------------------------------------------------------
# utility functions
#   - preview: image_ggplot(img)
#