Script to add a watermark to a directory of images.

batch_overlay_images.rb

ORIGINAL_DIR= 'fotos'
OUTPUT_DIR = 'overlayed'

OVERLAY_FILE = 'overlay.png'

class Composer

  def initialize(file_name)
    @file_name = file_name
  end

  def image_dimensions
    @image_dimensions ||= `identify -format '%wx%h' #{ORIGINAL_DIR}/#{@file_name}`
  end

  def image_height
    @h ||= image_dimensions.match(/x(\d+)/)[1]
  end

  def image_width
    @w ||= image_dimensions.match(/(\d+)x/)[1]
  end

  def overlay_width
    @overlay_width ||= image_width.to_i * 0.2
  end

  def overlay_height
    @overlay_height ||= image_height.to_i * 0.2
  end

  def add_watermark
    `composite -size 800x600 -quality 100% -gravity SouthEast -geometry #{overlay_width}x#{overlay_height}+100+100 #{OVERLAY_FILE} #{ORIGINAL_DIR}/#{@file_name} #{OUTPUT_DIR}/#{@file_name}`
  end

  def resize(dimension = "600x400")
    `convert #{OUTPUT_DIR}/#{@file_name} -resize #{dimension} #{OUTPUT_DIR}/#{@file_name}`
  end
end

Dir.foreach(ORIGINAL_DIR) do |file|
  next if file == '.' or file == '..'

  c = Composer.new(file)
  c.add_watermark

end