Class: Capybara::Screenshot::Diff::ImageCompare

Inherits:
Object
  • Object
show all
Defined in:
lib/capybara/screenshot/diff/image_compare.rb

Overview

Compare two image and determine if they are equal, different, or within some comparison range considering color values and difference area size.

Constant Summary collapse

TOLERABLE_OPTIONS = 
[:tolerance, :color_distance_limit, :shift_distance_limit, :area_size_limit].freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(image_path, base_image_path, options = {}) ⇒ ImageCompare

Returns a new instance of ImageCompare.



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# File 'lib/capybara/screenshot/diff/image_compare.rb', line 19

def initialize(image_path, base_image_path, options = {})
  @image_path = Pathname.new(image_path)
  @base_image_path = Pathname.new(base_image_path)

  @driver_options = options.dup

  @driver = Drivers.for(@driver_options)
end

Instance Attribute Details

#base_image_path ⇒ Object (readonly)

Returns the value of attribute base_image_path.



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# File 'lib/capybara/screenshot/diff/image_compare.rb', line 16

def base_image_path
  @base_image_path
end

#difference ⇒ Object

Returns the value of attribute difference.



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# File 'lib/capybara/screenshot/diff/image_compare.rb', line 17

def difference
  @difference
end

#driver ⇒ Object (readonly)

Returns the value of attribute driver.



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# File 'lib/capybara/screenshot/diff/image_compare.rb', line 15

def driver
  @driver
end

#driver_options ⇒ Object (readonly)

Returns the value of attribute driver_options.



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# File 'lib/capybara/screenshot/diff/image_compare.rb', line 15

def driver_options
  @driver_options
end

#error_message ⇒ Object (readonly)

Returns the value of attribute error_message.



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# File 'lib/capybara/screenshot/diff/image_compare.rb', line 17

def error_message
  @error_message
end

#image_path ⇒ Object (readonly)

Returns the value of attribute image_path.



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# File 'lib/capybara/screenshot/diff/image_compare.rb', line 16

def image_path
  @image_path
end

Instance Method Details

#different? ⇒ Boolean

Compare the two image referenced by this object, and return ‘true` if they are different, and `false` if they are the same.

Returns:

  • (Boolean) 


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# File 'lib/capybara/screenshot/diff/image_compare.rb', line 58

def different?
  processed.difference.different?
end

#processed ⇒ Object 



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# File 'lib/capybara/screenshot/diff/image_compare.rb', line 73

def processed
  self.difference = find_difference unless processed?
  @error_message ||= reporter.generate
  self
end

#processed? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/capybara/screenshot/diff/image_compare.rb', line 69

def processed?
  !!difference
end

#quick_equal? ⇒ Boolean

Compare the two image files and return ‘true` or `false` as quickly as possible. Return falsely if the old file does not exist or the image dimensions do not match.

Returns:

  • (Boolean) 


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# File 'lib/capybara/screenshot/diff/image_compare.rb', line 30

def quick_equal?
  require_images_exists!

  # NOTE: This is very fuzzy logic, but so far it's helps to support current performance.
  return true if new_file_size == old_file_size

  comparison = load_and_process_images

  unless driver.same_dimension?(comparison)
    self.difference = build_failed_difference(comparison, {different_dimensions: true})
    return false
  end

  if driver.same_pixels?(comparison)
    self.difference = build_no_difference(comparison)
    return true
  end

  # NOTE: Could not make any difference to be tolerable, so skip and return as not equal.
  return false if without_tolerable_options?

  self.difference = driver.find_difference_region(comparison)

  !difference.different?
end

#reporter ⇒ Object 



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# File 'lib/capybara/screenshot/diff/image_compare.rb', line 62

def reporter
  @reporter ||= begin
    current_difference = difference || build_no_difference(nil)
    Capybara::Screenshot::Diff::Reporters::Default.new(current_difference)
  end
end