image_compare.rb in capybara-screenshot-diff-0.2.1

- old
+ new

@@ -4,25 +4,35 @@
   module Screenshot
     module Diff
       class ImageCompare
         include ChunkyPNG::Color
 
-        def self.compare(file_name, old_file_name, dimensions = nil)
-          name = file_name.chomp('.png')
+        def self.compare(*args)
+          new(*args).compare
+        end
+
+        def initialize(old_file_name, new_file_name, dimensions = nil)
+          @old_file_name = old_file_name
+          @file_name = new_file_name
+          @dimensions = dimensions
+        end
+
+        def compare
+          name = @file_name.chomp('.png')
           org_file_name = "#{name}_0.png~"
           new_file_name = "#{name}_1.png~"
 
-          return nil unless File.exist? old_file_name
+          return nil unless File.exist? @old_file_name
 
-          images = load_images(old_file_name, file_name)
+          images = load_images(@old_file_name, @file_name)
 
           unless images
             clean_tmp_files(new_file_name, org_file_name)
             return false
           end
 
-          crop_images(images, dimensions) if dimensions
+          crop_images(images, @dimensions) if @dimensions
           org_img = images.first
           new_img = images.last
           if sizes_changed?(org_img, new_img, name)
             save_images(new_file_name, new_img, org_file_name, org_img)
             return true
@@ -31,89 +41,89 @@
           if org_img.pixels == new_img.pixels
             clean_tmp_files(new_file_name, org_file_name)
             return false
           end
 
-          bottom, left, right, top = find_diff_rectangle(org_img, new_img)
-          draw_rectangles(images, bottom, left, right, top)
+          @left, @top, @right, @bottom = find_diff_rectangle(org_img, new_img)
+          draw_rectangles(images, @bottom, @left, @right, @top)
           save_images(new_file_name, new_img, org_file_name, org_img)
           true
         end
 
-        def self.save_images(new_file_name, new_img, org_file_name, org_img)
+        def dimensions
+          [@left, @top, @right, @bottom]
+        end
+
+        private
+
+        def save_images(new_file_name, new_img, org_file_name, org_img)
           org_img.save(org_file_name)
           new_img.save(new_file_name)
         end
 
-        def self.clean_tmp_files(new_file_name, org_file_name)
-          File.delete(org_file_name) if File.exists?(org_file_name)
-          File.delete(new_file_name) if File.exists?(new_file_name)
+        def clean_tmp_files(new_file_name, org_file_name)
+          File.delete(org_file_name) if File.exist?(org_file_name)
+          File.delete(new_file_name) if File.exist?(new_file_name)
         end
 
-        private
+        def load_images(old_file_name, file_name)
+          old_file = File.binread(old_file_name)
+          new_file = File.binread(file_name)
 
-        def self.load_images(old_file_name, file_name)
-          old_file = File.read(old_file_name)
-          new_file = File.read(file_name)
-
           return false if old_file == new_file
 
           [ChunkyPNG::Image.from_blob(old_file), ChunkyPNG::Image.from_blob(new_file)]
         end
 
-        def self.sizes_changed?(org_image, new_image, name)
-          if org_image.dimension != new_image.dimension
-            puts "Image size has changed for #{name}: #{[org_image, new_image].map { |i| "#{i.width}x#{i.height}" }.join(' => ')}"
-            return true
-          end
+        def sizes_changed?(org_image, new_image, name)
+          return unless org_image.dimension != new_image.dimension
+          change_msg = [org_image, new_image].map { |i| "#{i.width}x#{i.height}" }.join(' => ')
+          puts "Image size has changed for #{name}: #{change_msg}"
+          true
         end
 
-        def self.crop_images(images, dimensions)
+        def crop_images(images, dimensions)
           images.map! do |i|
             if i.dimension.to_a == dimensions || i.width < dimensions[0] || i.height < dimensions[1]
               i
             else
               i.crop(0, 0, *dimensions)
             end
           end
         end
 
-        def self.draw_rectangles(images, bottom, left, right, top)
-          (1..2).each do |i|
-            images.each do |image|
-              image.rect(left - 1, top - 1, right + 1, bottom + 1, ChunkyPNG::Color.rgb(255, 0, 0))
-            end
+        def draw_rectangles(images, bottom, left, right, top)
+          images.each do |image|
+            image.rect(left - 1, top - 1, right + 1, bottom + 1, ChunkyPNG::Color.rgb(255, 0, 0))
           end
         end
 
-        def self.find_diff_rectangle(org_img, new_img)
+        def find_diff_rectangle(org_img, new_img)
           top = bottom = nil
           left = org_img.width
           right = -1
           org_img.height.times do |y|
             (0...left).find do |x|
-              if org_img[x, y] != new_img[x, y]
-                top ||= y
-                bottom = y
-                left = x
-                right = x if x > right
-              end
+              next if org_img[x, y] == new_img[x, y]
+              top ||= y
+              bottom = y
+              left = x
+              right = x if x > right
+              x
             end
             (org_img.width - 1).step(right + 1, -1).find do |x|
               if org_img[x, y] != new_img[x, y]
                 bottom = y
                 right = x
               end
             end
           end
           (org_img.height - 1).step(bottom + 1, -1).find do |y|
             ((left + 1)..(right - 1)).find do |x|
-              if org_img[x, y] != new_img[x, y]
-                bottom = y
-              end
+              bottom = y if org_img[x, y] != new_img[x, y]
             end
           end
-          return bottom, left, right, top
+          [left, top, right, bottom]
         end
       end
     end
   end
 end