m17n cargo cult. yob, plz investigate

lib/prawn/images/png.rb

@@ -1,4 +1,4 @@
-# encoding: utf-8
+# encoding: ASCII-8BIT
 
 # png.rb : Extracts the data from a PNG that is needed for embedding
 #
@@ -125,28 +125,28 @@ def unfilter_image_data
           row_data = data.slice! 0, scanline_length
           filter = row_data.shift
           case filter
-          when 0 then # None
-          when 1 then # Sub
+          when 0 # None
+          when 1 # Sub
             row_data.each_with_index do |byte, index|
               left = index < pixel_length ? 0 : row_data[index - pixel_length]
               row_data[index] = (byte + left) % 256
               #p [byte, left, row_data[index]]
             end
-          when 2 then # Up
+          when 2 # Up
             row_data.each_with_index do |byte, index|
               col = index / pixel_length
               upper = row == 0 ? 0 : pixels[row-1][col][index % pixel_length]
               row_data[index] = (upper + byte) % 256
             end
-          when 3 then # Average
+          when 3  # Average
             row_data.each_with_index do |byte, index|
               col = index / pixel_length
               upper = row == 0 ? 0 : pixels[row-1][col][index % pixel_length]
               left = index < pixel_length ? 0 : row_data[index - pixel_length]
 
               row_data[index] = (byte + ((left + upper)/2).floor) % 256
             end
-          when 4 then # Paeth
+          when 4 # Paeth
             left = upper = upper_left = nil
             row_data.each_with_index do |byte, index|
               col = index / pixel_length

spec/png_spec.rb

@@ -1,4 +1,4 @@
-# encoding: utf-8
+# encoding: ASCII-8BIT
 
 # Spec'ing the PNG class. Not complete yet - still needs to check the
 # contents of palette and transparency to ensure they're correct.
@@ -115,13 +115,13 @@
 
   it "should correctly return the raw image data (with no alpha channel) from the image data chunk" do
     png = Prawn::Images::PNG.new(@img_data)
-    data = File.open(@data_filename, "rb") { |f| f.read }
+    data = File.open(@data_filename, rb_flag) { |f| f.read }
     png.img_data.should == data
   end
 
   it "should correctly extract the alpha channel data from the image data chunk" do
     png = Prawn::Images::PNG.new(@img_data)
-    data = File.open(@alpha_data_filename, "rb") { |f| f.read }
+    data = File.open(@alpha_data_filename, rb_flag) { |f| f.read }
     png.alpha_channel.should == data
   end
 end
@@ -132,7 +132,7 @@
     @filename = "#{Prawn::BASEDIR}/data/images/dice.png"
     @data_filename = "#{Prawn::BASEDIR}/data/images/dice.dat"
     @alpha_data_filename = "#{Prawn::BASEDIR}/data/images/dice.alpha"
-    @img_data = File.open(@filename, "rb") { |f| f.read }
+    @img_data = File.open(@filename, "rb") { |f| f.read }       
   end
 
   it "should read the attributes from the header chunk correctly" do
@@ -149,13 +149,13 @@
 
   it "should correctly return the raw image data (with no alpha channel) from the image data chunk" do
     png = Prawn::Images::PNG.new(@img_data)
-    data = File.open(@data_filename, "rb") { |f| f.read }
+    data = File.open(@data_filename, rb_flag) { |f| f.read }     
     png.img_data.should == data
   end
 
   it "should correctly extract the alpha channel data from the image data chunk" do
     png = Prawn::Images::PNG.new(@img_data)
-    data = File.open(@alpha_data_filename, "rb") { |f| f.read }
+    data = File.open(@alpha_data_filename, rb_flag) { |f| f.read }
     png.alpha_channel.should == data
   end
 end

spec/spec_helper.rb

@@ -33,4 +33,8 @@ def observer(klass)
 def parse_pdf_object(obj)
   PDF::Reader::Parser.new(
      PDF::Reader::Buffer.new(sio = StringIO.new(obj)), nil).parse_token   
+end    
+
+def rb_flag
+  ruby_18 { "rb" } || ruby_19 { "rb:ASCII-8BIT" }
 end