Check a directory for transparent pngs recursively

Tagged with Ruby shell ImageMagick

Language: Ruby

This requires that you have ImageMagick installed on whatever machine you run it on as the `identify -format %A file.png` bit is actually a shell command for ImageMagick. Ruby just was easier for me to figure out how to recursively run that on all .png files in a given directory. I’m sure there is a shorter shell script to do the same thing. The script will probably run without ImageMagick installed, but it most likely won’t give any output.

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require 'find'

def find_and_print(path, pattern)
  Find.find(path) do |entry|
    if File.file?(entry) and entry[pattern]
      has_transparency = `identify -format %A #{entry}`
      if has_transparency.to_s.chomp.strip == "True"
        puts "#{entry}"
# print all the ruby files
find_and_print("/rails_app/public/images", /.+\.png$/)
Original snippet written by Jon Kinney
Last updated at 10:02 AM on Feb 02, 2010

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