Class: LookbookVisualTester::ImageComparator

Inherits:
Object
  • Object
show all
Defined in:
lib/lookbook_visual_tester/services/image_comparator.rb

Constant Summary collapse

DIFF_COLOR =

Neon Red for differences

ChunkyPNG::Color.from_hex('#FF073A')

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(baseline_path, current_path, diff_path) ⇒ ImageComparator

Returns a new instance of ImageComparator.



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# File 'lib/lookbook_visual_tester/services/image_comparator.rb', line 11

def initialize(baseline_path, current_path, diff_path)
  @baseline_path = baseline_path
  @current_path = current_path
  @diff_path = diff_path
end

Instance Attribute Details

#baseline_path ⇒ Object (readonly)

Returns the value of attribute baseline_path.



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# File 'lib/lookbook_visual_tester/services/image_comparator.rb', line 6

def baseline_path
  @baseline_path
end

#current_path ⇒ Object (readonly)

Returns the value of attribute current_path.



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# File 'lib/lookbook_visual_tester/services/image_comparator.rb', line 6

def current_path
  @current_path
end

#diff_path ⇒ Object (readonly)

Returns the value of attribute diff_path.



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# File 'lib/lookbook_visual_tester/services/image_comparator.rb', line 6

def diff_path
  @diff_path
end

Instance Method Details

#call ⇒ Object 



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# File 'lib/lookbook_visual_tester/services/image_comparator.rb', line 17

def call
  unless File.exist?(baseline_path)
    return { diff_path: nil, mismatch: 0.0, error: 'Baseline not found' }
  end

  baseline = ChunkyPNG::Image.from_file(baseline_path)
  current = ChunkyPNG::Image.from_file(current_path)

  max_width = [baseline.width, current.width].max
  max_height = [baseline.height, current.height].max

  diff_pixels_count = 0
  diff_image = ChunkyPNG::Image.new(max_width, max_height, ChunkyPNG::Color::WHITE)

  max_height.times do |y|
    max_width.times do |x|
      in_baseline = x < baseline.width && y < baseline.height
      in_current = x < current.width && y < current.height

      if in_baseline && in_current
        pixel1 = baseline[x, y]
        pixel2 = current[x, y]

        score = 0.0
        if pixel1 != pixel2
          score = ChunkyPNG::Color.euclidean_distance_rgba(pixel1, pixel2) / 510.0
        end

        if score <= LookbookVisualTester.config.tolerance
          # Match (including exact match where score is 0.0)
          # Blue context for unchanged pixels to make it easier for humans
          gray_val = ChunkyPNG::Color.r(ChunkyPNG::Color.grayscale_teint(pixel1))
          # Keep intensity in R/G but push blue to make it the dominant tint
          diff_image[x, y] = ChunkyPNG::Color.rgba(gray_val, gray_val, 255, 50)
        else
          diff_image[x, y] = DIFF_COLOR
          diff_pixels_count += 1
        end
      elsif in_baseline || in_current
        # Pixel exists in one but not the other -> Mismatch
        diff_image[x, y] = DIFF_COLOR
        diff_pixels_count += 1
      end
    end
  end

  mismatch_percentage = (diff_pixels_count.to_f / (max_width * max_height)) * 100.0

  if diff_pixels_count > 0
    FileUtils.mkdir_p(File.dirname(diff_path))
    diff_image.save(diff_path)
    { diff_path: diff_path, mismatch: mismatch_percentage, error: nil }
  else
    { diff_path: nil, mismatch: 0.0, error: nil }
  end
rescue StandardError => e
  { diff_path: nil, mismatch: 0.0, error: e.message }
end