1 files changed, 56 insertions, 0 deletions
diff --git a/tooling/lib/tooling/image.rb b/tooling/lib/tooling/image.rb
new file mode 100644
index 00000000000..d0c464b983c
--- /dev/null
+++ b/tooling/lib/tooling/image.rb
@@ -0,0 +1,56 @@
+# frozen_string_literal: true
+
+module Tooling
+  module Image
+    # Determine the tolerance till when we run pngquant in a loop
+    TOLERANCE = 10000
+
+    def self.check_executables
+      unless system('pngquant --version', out: File::NULL)
+        warn(
+          'Error: pngquant executable was not detected in the system.',
+          'Download pngquant at https://pngquant.org/ and place the executable in /usr/local/bin'
+        )
+        abort
+      end
+
+      unless system('gm version', out: File::NULL)
+        warn(
+          'Error: gm executable was not detected in the system.',
+          'Please install imagemagick: brew install imagemagick or sudo apt install imagemagick'
+        )
+        abort
+      end
+    end
+
+    def self.compress_image(file, keep_original = false)
+      check_executables
+
+      compressed_file = "#{file}.compressed"
+      FileUtils.copy(file, compressed_file)
+
+      pngquant_file = PngQuantizator::Image.new(compressed_file)
+
+      # Run the image repeatedly through pngquant until
+      # the change in file size is within TOLERANCE
+      # or the loop count is above 1000
+      1000.times do
+        before = File.size(compressed_file)
+        pngquant_file.quantize!
+        after = File.size(compressed_file)
+        break if before - after <= TOLERANCE
+      end
+
+      savings = File.size(file) - File.size(compressed_file)
+      is_uncompressed = savings > TOLERANCE
+
+      if is_uncompressed && !keep_original
+        FileUtils.copy(compressed_file, file)
+      end
+
+      FileUtils.remove(compressed_file)
+
+      [is_uncompressed, savings]
+    end
+  end
+end