Implementing rotate for save_png

lib/squib/api/save.rb

@@ -7,10 +7,11 @@ module Squib
     # @option opts [String] dir (_output) the directory for the output to be sent to. Will be created if it doesn't exist.
     # @option opts [Symbol] format (:png)  the format that this will be rendered too. Options `:pdf, :png`. Array of both is allowed: `[:pdf, :png]`
     # @option opts [String] prefix (card_) the prefix of the file name to be printed
+    # @option opts [Boolean] rotate (false) PNG saving only. If true, the saved cards will be rotated 90 degrees clockwise. Intended to rendering landscape instead of portrait.
     # @return self
     # @api public
     def save(opts = {})
-      opts = needs(opts, [:range, :creatable_dir, :formats, :prefix])
+      opts = needs(opts, [:range, :creatable_dir, :formats, :prefix, :rotate])
       save_png(opts) if opts[:format].include? :png
       save_pdf(opts) if opts[:format].include? :pdf
       self
@@ -24,17 +25,19 @@ module Squib
     # @option opts [Enumerable] range (:all) the range of cards over which this will be rendered. See {file:README.md#Specifying_Ranges Specifying Ranges}
     # @option opts [String] dir (_output) the directory for the output to be sent to. Will be created if it doesn't exist.
     # @option opts [String] prefix (card_) the prefix of the file name to be printed.
+    # @option opts [Boolean] rotate (false) if true, the saved cards will be rotated 90 degrees clockwise. Intended to rendering landscape instead of portrait.
     # @return [nil] Returns nothing
     # @api public
     def save_png(opts = {})
-      opts = needs(opts,[:range, :creatable_dir, :prefix])
+      opts = needs(opts,[:range, :creatable_dir, :prefix, :rotate])
       @progress_bar.start("Saving PNGs to #{opts[:dir]}/#{opts[:prefix]}*") do |bar|
         opts[:range].each do |i| 
-          @cards[i].save_png(i, opts[:dir], opts[:prefix])
+          @cards[i].save_png(i, opts[:dir], opts[:prefix], opts[:rotate])
           bar.increment
         end
       end
     end
 
   end
-end
+end
+

lib/squib/constants.rb

@@ -20,6 +20,7 @@ module Squib
       :prefix => "card_",
       :progress_bar => false,
       :range => :all,
+      :rotate => false,
       :sheet => 0,
       :spacing => 0,
       :str => '',

lib/squib/graphics/save_images.rb

@@ -3,8 +3,30 @@ module Squib
 
     # :nodoc:
     # @api private 
-    def save_png(i, dir, prefix)
-      cairo_context.target.write_to_png("#{dir}/#{prefix}#{i}.png")
+    def save_png(i, dir, prefix, rotate)
+      if rotate
+        surface = rotated_image
+      else
+        surface = @cairo_surface
+      end
+      write_png(surface, i, dir, prefix)
+    end
+
+    # :nodoc:
+    # @api private
+    def rotated_image
+      rotated_cc = Cairo::Context.new(Cairo::ImageSurface.new(@height, @width) )
+      rotated_cc.translate(@height * 0.5, @width * 0.5)
+      rotated_cc.rotate(0.5 * Math::PI)
+      rotated_cc.translate(@width * -0.5, @height * -0.5)
+      rotated_cc.set_source(@cairo_surface)
+      rotated_cc.paint
+      rotated_cc.target
+    end
+    # :nodoc:
+    # @api private 
+    def write_png(surface, i, dir, prefix)
+      surface.write_to_png("#{dir}/#{prefix}#{i}.png")
     end
 
   end