Class: Kontrast::ImageHelper

Inherits:
Object
  • Object
show all
Defined in:
lib/kontrast/image_helper.rb

Instance Method Summary collapse

Constructor Details

#initialize(img1_path, img2_path) ⇒ ImageHelper

Returns a new instance of ImageHelper.



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# File 'lib/kontrast/image_helper.rb', line 7

def initialize(img1_path, img2_path)
    @img1_path, @img2_path = img1_path, img2_path
    @img1 = load_image(@img1_path)
    @img2 = load_image(@img2_path)
    @path = Kontrast.path
end

Instance Method Details

#compare(output_dir, output_file_name) ⇒ Object

Uses the compare_channel function to highlight the differences between two images Docs: www.rubydoc.info/github/gemhome/rmagick/Magick%2FImage%3Acompare_channel



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# File 'lib/kontrast/image_helper.rb', line 40

def compare(output_dir, output_file_name)
    begin
        distortion_metric = Magick.const_get(Kontrast.configuration.distortion_metric)
        diff = @img1.compare_channel(@img2, distortion_metric) do |options|
            options.highlight_color = Kontrast.configuration.highlight_color
            options.lowlight_color = Kontrast.configuration.lowlight_color
        end

        output_path = "#{Kontrast.path}/#{output_dir}"
        FileUtils.mkdir_p(output_path) # Just in case
        diff.first.write(File.join(output_path, output_file_name))

        # diff is an array, the last (second) value is the diff value,
        # a float between 0 and 1, 0 being the same image, 1 being an
        # entirely different image
        return diff.last
    rescue Magick::ImageMagickError => e
        puts "Error comparing images: #{e.message}"
        # 1 means that both images are different
        return 1
    end
end

#crop(width) ⇒ Object 



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# File 'lib/kontrast/image_helper.rb', line 23

def crop(width)
    # Let's not do anything if the images are already the same size
    return if @img1.rows == @img2.rows

    # Get max height of both images
    max_height = [@img1.rows, @img2.rows].max

    # Crop
    Workers.map([@img1, @img2]) do |image|
        image.extent(width, max_height).write(image.filename)
    end
    reload_images
end

#load_image(path) ⇒ Object 



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# File 'lib/kontrast/image_helper.rb', line 19

def load_image(path)
    return Magick::Image.read(path).first
end

#reload_images ⇒ Object 



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# File 'lib/kontrast/image_helper.rb', line 14

def reload_images
    @img1 = load_image(@img1_path)
    @img2 = load_image(@img2_path)
end