R/functions.R

In ThinkRstat/spongecake: Transform a Movie into a Synthetic Picture

# -*- coding: utf-8 -*-
#' @encoding UTF-8
#' @title average_color
#' @description return the average color from an image
#' @param img the image (a array)
#' @importFrom grDevices rgb


average_color <- function(img) {
  if (is.null(dim(img))) {
    val <- img

  } else {
    val <- colMeans(img, dims = 2)

  }
  list(rgb = val, html = rgb(val[1], val[2], val[3]))
}


# -*- coding: utf-8 -*-
#' @encoding UTF-8
#' @title folder_average_color
#' @description return the average color from all folder's images
#' @param folder the path of the folder
#' @importFrom jpeg readJPEG
#' @importFrom magrittr %>%
#' @importFrom plyr llply
#' @importFrom stats na.omit


folder_average_color <- function(folder){
  list.files(folder,pattern = "*.jpeg$",full.names = TRUE) %>%
    llply(.,.fun=function(x){
      res <- NA;
      try(res <- average_color(readJPEG(x))$html)
      res
    },.progress = "text")  %>%
    unlist() %>%
    na.omit() %>%
    as.vector()
}

# -*- coding: utf-8 -*-
#' @encoding UTF-8
#' @title gen_screenshot
#' @description transform a movie into lot of screenshots
#' @param movie the path of the movie
#' @param folder the path of the folder
#' @param every timbe between each screenshot in seconds
#' @examples
#' \dontrun{
#' gen_screenshot(movie = "D:/mymovie.avi") %>%
#' browseURL()
#' }
#' @export


gen_screenshot <- function(movie,folder=tempfile(),every=10){

  if(!file.exists(movie)){
    stop('The movie "', movie, '" dont seems to exists, can you check the path and retry ?')
    return()

  }


  if (getOption('ffmpeg')=="") {
    message('The command "',
            ifelse(
              is.null(getOption('ffmpeg')) || getOption('ffmpeg')=="" ,
              "ffmpeg",
              getOption('ffmpeg')
            )
                          ,'" is not available in your system. Please install FFmpeg first\n more information at : \n',
                          ifelse(.Platform$OS.type == 'windows', 'https://ffmpeg.zeranoe.com/builds/',
                                 'http://ffmpeg.org/download.html'))
    message('if you already have installed ffmpeg use this instruction to manualy edit the path to ffmpeg :')
    message(ifelse(.Platform$OS.type == 'windows', ' options(ffmpeg = "C:/path/to/bin/ffmpeg.exe")',
                                 'options(ffmpeg = "path/to/ffmpeg")'))
  }


  try(dir.create(folder))
  cat(folder,"\n\n\n")
  td <- paste0(shQuote(getOption('ffmpeg'))," -i ",shQuote(file.path(movie))," -vf fps=1/",every,"  ",folder,"/image-%04d.jpeg")
  td
  cat(system.time(system(td)))
  return(folder)
}




# -*- coding: utf-8 -*-
#' @encoding UTF-8
#' @title draw
#' @description transform a folder of scrennshot into a synthetical picture
#' @param folder the path of the folder
#' @importFrom ggplot2 ggplot aes_string geom_bar coord_flip theme_void
#' @export
#' @examples
#' \dontrun{
#' #options(ffmpeg = "C:/ffmpeg-3.1.4-win64-static/bin/ffmpeg.exe") # windows user
#' library(magrittr)
#' gen_screenshot(movie = "D:/mymovie.avi") %>%
#' draw()
#' }



draw <- function(folder){
  jj <- folder_average_color(folder)
  data.frame(trt = jj, outcome = rep(1,length(jj))) %>%
    ggplot(., aes_string("trt", "outcome")) +
    geom_bar(stat = "identity", position = "fill",fill=jj,width=1)+
    coord_flip()+ theme_void()
}