convert_vic2_screensh

#!/usr/bin/env ruby

require "pathname"
require "tempfile"

def strip_alpha!(input_path, output_path)
  bmp = File.open(input_path, "rb").read
  header = bmp[0, 54]
  image = bmp[54..-3]
  final = bmp[-2..-1]
  raise unless image.size % 4 # WTF last 2 bytes

  image_out = ""
  (image.size/4).times do |i|
    r,g,b,a = image[i*4, 4].unpack("CCCC")
    image_out << [r,g,b,255].pack("CCCC")
  end
  open(output_path, "wb") do |fh|
    fh.write header
    fh.write image_out
    fh.write final
  end
end

def convert_screenshot!(input_path)
  output_path = Pathname(File.basename(input_path, ".bmp") + ".png")
  input_path = Pathname(input_path)
  return if output_path.exist?

  mid_file = Tempfile.new(['foo', '.bmp'])
  strip_alpha!(input_path, mid_file.path)
  system "convert", mid_file.path, output_path.to_s
end

ARGV.each do |path|
  convert_screenshot!(path)
end