require_relative 'os' module Capybara module Screenshot module Diff module Stabilization include Os IMAGE_WAIT_SCRIPT = <<-JS.strip_heredoc.freeze function pending_image() { var images = document.images; for (var i = 0; i < images.length; i++) { if (!images[i].complete) { return images[i].src; } } return false; }() JS def take_stable_screenshot(comparison, color_distance_limit:, area_size_limit:) input = prepare_page_for_screenshot previous_file_name = comparison.old_file_name screenshot_started_at = last_image_change_at = Time.now loop.with_index do |_x, i| take_right_size_screenshot(comparison) break unless Capybara::Screenshot.stability_time_limit if comparison.quick_equal? clean_stabilization_images(comparison.new_file_name) break end comparison.reset if previous_file_name stabilization_comparison = ImageCompare.new(comparison.new_file_name, previous_file_name, color_distance_limit: color_distance_limit, area_size_limit: area_size_limit) if stabilization_comparison.quick_equal? if (Time.now - last_image_change_at) > Capybara::Screenshot.stability_time_limit clean_stabilization_images(comparison.new_file_name) break end next else last_image_change_at = Time.now end check_max_wait_time(comparison, screenshot_started_at) end previous_file_name = "#{comparison.new_file_name.chomp('.png')}_x#{format('%02i', i)}.png~" FileUtils.mv comparison.new_file_name, previous_file_name end ensure input.click if input end private private def reduce_retina_image_size(file_name) return if !ON_MAC || !selenium? || !Capybara::Screenshot.window_size saved_image = ChunkyPNG::Image.from_file(file_name) width = Capybara::Screenshot.window_size[0] return if saved_image.width < width * 2 height = (width * saved_image.height) / saved_image.width resized_image = saved_image.resample_bilinear(width, height) resized_image.save(file_name) end private def stabilization_images(base_file) Dir["#{base_file.chomp('.png')}_x*.png~"] end private def clean_stabilization_images(base_file) FileUtils.rm stabilization_images(base_file) end private def prepare_page_for_screenshot assert_images_loaded if Capybara::Screenshot.blur_active_element active_element = execute_script(<<-JS) ae = document.activeElement; if (ae.nodeName == "INPUT" || ae.nodeName == "TEXTAREA") { ae.blur(); return ae; } return null; JS input = page.driver.send :unwrap_script_result, active_element end input end private def take_right_size_screenshot(comparison) save_screenshot(comparison.new_file_name) # TODO(uwe): Remove when chromedriver takes right size screenshots reduce_retina_image_size(comparison.new_file_name) # ODOT end private def check_max_wait_time(comparison, screenshot_started_at) assert (Time.now - screenshot_started_at) < Capybara.default_max_wait_time, "Could not get stable screenshot within #{Capybara.default_max_wait_time}s\n" \ "#{stabilization_images(comparison.new_file_name).join("\n")}" end private def assert_images_loaded(timeout: Capybara.default_max_wait_time) return unless respond_to? :evaluate_script start = Time.now loop do pending_image = evaluate_script IMAGE_WAIT_SCRIPT break unless pending_image assert (Time.now - start) < timeout, "Images not loaded after #{timeout}s: #{pending_image.inspect}" sleep 0.1 end end end end end end