add suffix option

closes #268

lib/squib/args/save_batch.rb

@@ -20,6 +20,7 @@ module Squib::Args
         dir: '_output',
         prefix: 'card_',
         rotate: false,
+        suffix: '',
         trim_radius: 0,
         trim: 0,
       }
@@ -53,11 +54,11 @@ module Squib::Args
     end
 
     def full_filename(i)
-      "#{dir[i]}/#{prefix[i]}#{count_format[i] % i}.png"
+      "#{dir[i]}/#{prefix[i]}#{count_format[i] % i}#{suffix[i]}.png"
     end
 
     def summary
-      "#{dir[0]}/#{prefix[0]}_*"
+      "#{dir[0]}/#{prefix[0]}_*#{suffix[0]}"
     end
 
   end

lib/squib/args/sheet.rb

@@ -35,6 +35,7 @@ module Squib::Args
         height: 2550,
         margin: 75,
         prefix: 'sheet_',
+        suffix: '',
         rows: :infinite,
         columns: 5,
         trim_radius: 0,
@@ -95,7 +96,7 @@ module Squib::Args
       if i.nil?
         "#{dir}/#{file}"
       else
-        "#{dir}/#{prefix}#{count_format % i}.png"
+        "#{dir}/#{prefix}#{count_format % i}#{suffix}.png"
       end
     end
 

lib/squib/dsl/save_png.rb

@@ -22,7 +22,7 @@ module Squib
       def self.accepted_params
         %i(
           range
-          dir prefix count_format
+          dir prefix suffix count_format
           rotate trim trim_radius
          )
       end

lib/squib/dsl/save_sheet.rb

@@ -29,7 +29,7 @@ module Squib
         %i(
           range sprue
           columns rows rtl
-          prefix count_format dir
+          dir prefix count_format suffix
           margin gap trim trim_radius
          )
       end

lib/squib/graphics/save_images.rb

@@ -10,7 +10,7 @@ module Squib
                 else
                   @cairo_surface
                 end
-      write_png(surface, index, batch.dir, batch.prefix, batch.count_format)
+      write_png(surface, index, batch)
     end
 
     # :nodoc:
@@ -44,8 +44,8 @@ module Squib
       return new_cc.target
     end
 
-    def write_png(surface, i, dir, prefix, count_format)
-      surface.write_to_png("#{dir}/#{prefix}#{count_format % i}.png")
+    def write_png(surface, i, b)
+      surface.write_to_png("#{b.dir}/#{b.prefix}#{b.count_format % i}#{b.suffix}.png")
     end
 
   end