Move mouse with a laser pointer

lasermouse.R

library(Rvision)


X <- 1920
Y <- 1080
corners_screen <- matrix(c(0, Y,
                           X, Y,
                           X, 0,
                           0, 0), 
                         ncol = 2, byrow = TRUE)


# Works on linux w/ xdotool
mouse_move <- function(x, y) { 
  system(paste0("xdotool mousemove ", x, " ", y)) 
}

countdown <- function(time = 3) {
  for (t in seq_len(time)) {
    cat("\r")
    cat(t)
    beepr::beep(1)
    Sys.sleep(1)
  }
  beepr::beep(2)
}


grab_max_red <- function(image) {
  image |> 
    extractChannel(3) |> 
    minMaxLoc() |> 
    _[2, ]
}

# Not used for now. 
callibrate_threshold <- function(frames = 30, time = 3) {
  maximum_no_laser <- 0
  for (f in seq_len(frames)) {
    maximum_no_laser <- max(maximum_no_laser, grab_max_red(readNext(my_stream))[[1]])
    Sys.sleep(time/frames)
  }
  
  message("Point laser at screen")
  Sys.sleep(3)
  
  minimum_laser <- 255
  for (f in seq_len(frames)) {
    minimum_laser <- min(minimum_laser, grab_max_red(readNext(my_stream))[[1]])
    Sys.sleep(time/frames)
  }
  
  (minimum_laser + maximum_no_laser)/2 
}

get_corner <- function(which, stream_index = 0) {
  # We need to open and close the stream because otherwise nextFrame doesn't 
  # return the lastest frame. 
  stream <- stream(index = stream_index)
  on.exit(release(stream))
  message(paste0("Point the laser to the ", which, " corner of the screen..."))
  countdown(3)
  
  image <- readNext(stream)
  # plot(image)
  max <- grab_max_red(image)
  c(max[[2]], max[[3]])
}

grab_corners <- function(stream_index = 0, threshold = 200) {
  corners <- c("bottom left",
               "bottom right",
               "top right",
               "top left")
  
  corners_canvas <- t(vapply(corners, get_corner, FUN.VALUE = numeric(2), stream_index = stream_index))
  
  return(corners_canvas)
}



capture <- function(stream_index = 0, 
                    time = Inf, 
                    threshold = 200, 
                    corners_canvas = grab_corners(stream_index = stream_index)) {
  force(corners_canvas)   # We need to grab the corners before starting the stream
  stream <- stream(index = stream_index)
  on.exit(release(stream))

  M <- getPerspectiveTransform(from = corners_canvas, 
                               to = corners_screen, 
                               from_dim = dim(stream),
                               to_dim = c(Y, X))
  
  # newDisplay("My display", nrow(stream) / 2, ncol(stream) / 2) 
  # on.exit(destroyDisplay("My display"), add = TRUE)

  end <- as.numeric(Sys.time()) + time
  while (as.numeric(Sys.time()) < end) {
    image <- readNext(stream) |> 
      warpPerspective(M, inverse_map = FALSE, output_size = c(Y, X)) 
    # display(image, "My display", 25, nrow(stream) / 2, ncol(stream) / 2)
    max <- grab_max_red(image)
    
    
    if (max[[1]] >= threshold) {
      print(max)  # For debugging
      mouse_move(max[[2]], max[[3]])
    }
  }
}

capture()