Add dither server

bin/dither/dither.rb

@@ -0,0 +1,40 @@
+require "sinatra"
+require "mini_magick"
+
+MiniMagick.logger.level = Logger::DEBUG
+
+ROOT = ENV["ROOT"]
+KEY = ENV["KEY"]
+
+FileUtils.mkdir_p "tmp"
+
+get "/*" do |path|
+  filename = File.basename(path)
+  geometry = params["geo"]
+
+  @decrypted = Tempfile.new(filename, "tmp")
+  @dithered = Tempfile.new([filename, ".png"], "tmp")
+
+  %x(
+    openssl \
+      aes-256-cbc \
+      -d \
+      -in #{ROOT}/#{path}.enc \
+      -out #{@decrypted.path} \
+      -pass file:#{KEY} \
+      -iter 1000000
+  )
+
+  MiniMagick::Tool::Magick.new do |magick|
+    magick << @decrypted.path
+    magick.resize "#{geometry}^"
+    magick.gravity "center"
+    magick.extent geometry
+    magick.ordered_dither "o8x8"
+    magick.monochrome
+    magick << @dithered.path
+  end
+
+  content_type "image/png"
+  File.open(@dithered.path)
+end