[Ruby] make thumbnails

require "FileUtils"
require "ftools"

filetype = ".jpg"
path_in = Dir.pwd

path_out=path_in+"/thumbnail"
if !FileTest::directory?(path_out)
    Dir::mkdir(path_out)
end

dir=Dir.open(path_in)
a=Array.new(dir.collect.length)
num=0
dir.each do |file|
    if(file.length>filetype.length)
        if (file[file.length-4..file.length]==filetype)
            a[num]=file
            num=num+1
        end
    end
end
puts num

for i in 0..num-1
    fold = path_in + "/" + a[i]
    fnew_ppm = path_out + "/" + a[i][0..a[i].length-5]+".ppm"
    fnew_jpg = path_out + "/" + a[i][0..a[i].length-5]+".jpg"

    cmdline="convert -resize 200x -quality 100 "+fold+" "+fnew_ppm
    puts cmdline
    system("#{cmdline}")
   
    cmdline="convert -quality 100 "+fnew_ppm+" "+fnew_jpg
    puts cmdline
    system("#{cmdline}")

    puts "---------------------"
    File.delete(fnew_ppm)
end