Simplifies PNG export, removes ChunkyPNG resizing

lib/rqrcode/export/png.rb

@@ -8,10 +8,25 @@ module PNG
 
       # Render the PNG from the Qrcode.
       #
-      # Options:
-      # module_px_size  - Image size, in pixels.
+      # There are two sizing algoritams.
+      #
+      # - Original that can result in blurry and hard to scan images
+      # - Google's Chart API inspired sizing that risizes the module size to fit within the given image size.
+      # 
+      # The Googleis one will be used when no options are given or when the new size option is used.
+      #
+      # Options: 
       # fill  - Background ChunkyPNG::Color, defaults to 'white'
       # color - Foreground ChunkyPNG::Color, defaults to 'black'
+      #
+      # *Googleis*    
+      # size            - Total size of PNG in pixels. The module size is calculated so it fits. (defaults to 90)
+      # border_modules  - Width of white border around in modules. (defaults to 4).
+      #
+      #  -- DONT USE border_modules OPTION UNLESS YOU KNOW ABOUT THE QUIET ZONE NEEDS OF QR CODES --
+      #
+      # *Original*
+      # module_px_size  - Image size, in pixels.
       # border - Border thickness, in pixels
       #
       # It first creates an image where 1px = 1 module, then resizes.
@@ -24,30 +39,53 @@ def as_png(options = {})
           :resize_exactly_to => false,
           :fill => 'white',
           :color => 'black',
+          :size => 120,
           :border_modules => 4,
           :file => false,
           :module_px_size => 6
         }
+
+        googleis = options.length == 0 || (options[:size] != nil)
+
         options = default_img_options.merge(options) # reverse_merge
 
         fill   = ChunkyPNG::Color(options[:fill])
         color  = ChunkyPNG::Color(options[:color])
         output_file = options[:file]
-        border = options[:border_modules]
-        total_border = border * 2
-        module_px_size = if options[:resize_gte_to]
-          (options[:resize_gte_to].to_f / (self.module_count + total_border).to_f).ceil.to_i
+
+        module_px_size = nil
+        border_px = nil
+        png = nil
+
+        if googleis
+          total_image_size = options[:size]
+          border_modules = options[:border_modules]
+
+          module_px_size = (total_image_size.to_f / (self.module_count + 2 * border_modules).to_f).floor.to_i
+
+          img_size = module_px_size * self.module_count
+
+          remaining = total_image_size - img_size
+          border_px = (remaining / 2.0).floor.to_i
+
+          png = ChunkyPNG::Image.new(total_image_size, total_image_size, fill)
         else
-          options[:module_px_size]
-        end
-        border_px = border *  module_px_size
-        total_border_px = border_px * 2
-        resize_to = options[:resize_exactly_to]
+          border = options[:border_modules]
+          total_border = border * 2
+          module_px_size = if options[:resize_gte_to]
+            (options[:resize_gte_to].to_f / (self.module_count + total_border).to_f).ceil.to_i
+          else
+            options[:module_px_size]
+          end
+          border_px = border *  module_px_size
+          total_border_px = border_px * 2
+          resize_to = options[:resize_exactly_to]
 
-        img_size = module_px_size * self.module_count
-        total_img_size = img_size + total_border_px
+          img_size = module_px_size * self.module_count
+          total_img_size = img_size + total_border_px
 
-        png = ChunkyPNG::Image.new(total_img_size, total_img_size, fill)
+          png = ChunkyPNG::Image.new(total_img_size, total_img_size, fill)
+        end
 
         self.modules.each_index do |x|
           self.modules.each_index do |y|
@@ -60,8 +98,11 @@ def as_png(options = {})
             end
           end
         end
+
+        if !googleis && resize_to
+          png = png.resize(resize_to, resize_to)  
+        end
 
-        png = png.resize(resize_to, resize_to) if resize_to
 
         if output_file
           png.save(output_file,{ :color_mode => ChunkyPNG::COLOR_GRAYSCALE, :bit_depth =>1})