added all the documentation

README.md

@@ -77,5 +77,5 @@ Bug reports and pull requests are welcome on GitHub at https://github.com/timkae
 
 ## License
 
-The gem is available as open source under the terms of the [MIT License](http://opensource.org/licenses/MIT).
+The gem is available as open source under the terms of the GNU GPL v2.
 

lib/edge_detect.rb

@@ -9,3 +9,9 @@ require 'edge_detect/horizontal_differ'
 require 'edge_detect/vertical_differ'
 require 'edge_detect/edge_detector'
 require 'edge_detect/sobel_edge_detector'
+
+##
+# EdgeDetection module
+# 
+module EdgeDetect
+end

lib/edge_detect/differ.rb

@@ -1,16 +1,37 @@
 module EdgeDetect
   
+  ## 
+  # Abstract base class that provides the basis for both, 
+  # the horizontal and vertical differ.
+  #
   class Differ
 
+    ## 
+    # Initializes a new differ with a given image
+    # 
+    # @param image [ChunkyPNG::Image] the image that should be diffed
+    #
     def initialize(image)
       @image = image
       @gray_scaler = GrayScaler.new(image)
     end
 
+    ## 
+    # Should return the diffed value of the given pixel.
+    # If the pixel is out of bounds 0 should be returned.
+    # 
+    # @return [Integer] a value between 0 and 255 representing a grayscale value.
+    #
     def [](x, y)
       raise NotImplementedError
     end
 
+    ##
+    # Returns the nearby diffs of the given coordinates (x, y) with respect to 
+    # the given radius.
+    #
+    # @return [Array<Array<Integer>>] a two dimensional array with the diffs.
+    #
     def nearby(x, y, radius)
       output = []
       ((x - radius)..(x + radius)).each do |i|

lib/edge_detect/edge_detector.rb

@@ -2,14 +2,33 @@ require 'matrix'
 
 module EdgeDetect
 
+  ##
+  # Naive EdgeDetect Implementation
+  #
   class EdgeDetector
 
+    ##
+    # The original image
+    #
     attr_reader :image
 
+    ## 
+    # Initializes a new EdgeDetector with the given image.
+    # 
+    # @param image [ChunkyPNG::Image] the image that should be edge detected.
+    #
     def initialize(image)
       @image = image
     end
 
+    ##
+    # Edge detects the image by building the horizontal and vertical diffs. 
+    # (naive approach)
+    # 
+    # The original image will not be changed by this operation.
+    # 
+    # @return [ChunkyPNG::Image] the edge detected image.
+    #
     def detect_edges
       image = ChunkyPNG::Image.new(@image.width, @image.height, ChunkyPNG::Color::TRANSPARENT)
       h_diff = HorizontalDiffer.new(self.image)

lib/edge_detect/gray_scaler.rb

@@ -1,10 +1,24 @@
 module EdgeDetect
+  ##
+  # Grayscales a given image
+  # 
   class GrayScaler
 
+    ## 
+    # Initializes a new GrayScaler with the given image
+    #
+    # @param image [ChunkyPNG::Image] the image that should be grayscaled.
+    #
     def initialize(image)
       @image = image
     end
 
+    ## 
+    # Returns the grayscale value of the given coordinate. 
+    # If the coordinate is out of bounds 0 will be returned.
+    #
+    # @return [Integer] a value between 0 and 255.
+    #
     def [](x, y)
       begin
         (ChunkyPNG::Color.to_grayscale(@image[x, y]) & 0x0000ff00) >> 8
@@ -13,6 +27,12 @@ module EdgeDetect
       end
     end
 
+    ##
+    # Returns the nearby grayscale values of the given coordinates (x, y) with 
+    # respect to the given radius.
+    #
+    # @return [Array<Array<Integer>>] a two dimensional array with the grayscale values.
+    #
     def nearby(x, y, radius)
       output = []
       ((x - radius)..(x + radius)).each do |i|

lib/edge_detect/horizontal_differ.rb

@@ -1,8 +1,19 @@
 module EdgeDetect
   
-  # Simple Datastructure to hold horizontal and vertical diffs as one object
+  ## 
+  # Diffs the image horizontal.
+  #
   class HorizontalDiffer < Differ
 
+    ##
+    # Calculates the diff of the the given coordinate relative to the
+    # above pixel in the same column. 
+    # 
+    # The calculation is operated on the gray scale value of pixel 
+    # If the given coordinate is out of bounds 0 (black) will be returned.
+    #
+    # @return [Integer] a value between 0 and 255
+    #
     def [](x, y)
       begin
         @gray_scaler[x, y] - @gray_scaler[x, y - 1]

lib/edge_detect/sobel_edge_detector.rb

@@ -1,5 +1,17 @@
 module EdgeDetect
+
+  ##
+  # Sobel EdgeDetect Implementation
+  #
   class SobelEdgeDetector < EdgeDetector
+
+    ##
+    # Edge detects the image by applying the sobel operations.
+    # 
+    # The original image will not be changed by this operation.
+    # 
+    # @return [ChunkyPNG::Image] the edge detected image.
+    #
     def detect_edges
       image = ChunkyPNG::Image.new(@image.width, @image.height, ChunkyPNG::Color::TRANSPARENT)
       gray = GrayScaler.new(self.image)
@@ -19,6 +31,11 @@ module EdgeDetect
 
     private
 
+      ## 
+      # The sobel matrix to transform horizontal pixels
+      #
+      # @return [Matrix] the sobel matrix
+      #
       def sobel_x
         @sobel_x ||= Matrix[
           [1, 0, -1],
@@ -27,6 +44,11 @@ module EdgeDetect
         ]
       end
 
+      ## 
+      # The sobel matrix to transform vertical pixels
+      #
+      # @return [Matrix] the sobel matrix
+      #
       def sobel_y
         @sobel_y ||= Matrix[
           [1,   2,  1],

lib/edge_detect/version.rb

@@ -1,3 +1,6 @@
 module EdgeDetect
+  ## 
+  # The version of the gem
+  #
   VERSION = "0.1.0"
 end

lib/edge_detect/vertical_differ.rb

@@ -1,8 +1,19 @@
 module EdgeDetect
   
-  # Simple Datastructure to hold horizontal and vertical diffs as one object
+  ## 
+  # Diffs the image vertical.
+  #
   class VerticalDiffer < Differ
 
+    ##
+    # Calculates the diff of the the given coordinate relative to the
+    # above pixel in the same column. 
+    # 
+    # The calculation is operated on the gray scale value of pixel.
+    # If the given coordinate is out of bounds 0 (black) will be returned.
+    # 
+    # @return [Integer] a value between 0 and 255
+    #
     def [](x, y)
       begin
         @gray_scaler[x, y] - @gray_scaler[x - 1, y]

test/edge_detect/edge_detector_test.rb

@@ -3,7 +3,7 @@ require 'test_helper'
 class EdgeDetectorTest < Minitest::Test
 
 
-  def test_vertical_line
+  def test_airplane
     input = File.expand_path('../../pictures/airplane.png', __FILE__)
     image = ChunkyPNG::Image.from_file(input)
 
@@ -17,7 +17,7 @@ class EdgeDetectorTest < Minitest::Test
     sobel.detect_edges.save(output_sobel)
   end
 
-  def test_horizontal_line
+  def test_robot
     input = File.expand_path('../../pictures/robot.png', __FILE__)
     image = ChunkyPNG::Image.from_file(input)
 
@@ -31,6 +31,4 @@ class EdgeDetectorTest < Minitest::Test
     sobel.detect_edges.save(output_sobel)
   end
 
-
-
 end