Generate a grid background image with the --grid-img command line option.

lib/compass/commands/generate_grid_background.rb

@@ -0,0 +1,27 @@
+require File.join(File.dirname(__FILE__), 'project_base')
+require File.join(File.dirname(__FILE__), 'update_project')
+require File.join(File.dirname(__FILE__), '..', 'grid_builder')
+
+module Compass
+  module Commands
+    class GenerateGridBackground < ProjectBase
+      include Actions
+      def initialize(working_path, options)
+        super
+        assert_project_directory_exists!
+      end
+
+      def perform
+        read_project_configuration
+        Compass.configuration.set_maybe(options)
+        Compass.configuration.set_defaults!
+        column_width, gutter_width = options[:grid_dimensions].split(/\+/).map{|d| d.to_i}
+        unless GridBuilder.new(options.merge(:column_width => column_width, :gutter_width => gutter_width, :output_path => projectize(project_images_subdirectory), :working_path => self.working_path)).generate!
+          puts "ERROR: Some library dependencies appear to be missing."
+          puts "Have you installed rmagick? If not, please run:"
+          puts "sudo gem install rmagick"
+        end
+      end
+    end
+  end
+end

lib/compass/commands/project_base.rb

@@ -33,6 +33,10 @@ module Compass
         Compass.configuration.sass_dir
       end
 
+      def project_images_subdirectory
+        Compass.configuration.images_dir
+      end
+
       # Read the configuration file for this project
       def read_project_configuration
         if File.exists?(projectize('config.rb'))

lib/compass/configuration.rb

@@ -73,6 +73,10 @@ module Compass
       "stylesheets"
     end
 
+    def default_images_dir
+      "images"
+    end
+
     def default_output_style
       if environment == :development
         :expanded

lib/compass/exec.rb

@@ -170,6 +170,16 @@ END
         opts.on_tail("-v", "--version", "Print version") do
           self.options[:command] = :print_version
         end
+
+        opts.on('--grid-img [DIMENSIONS]', 'Generate a background image to test grid alignment. Dimension is given as <column_width>+<gutter_width>. Defaults to 30+10.') do |dimensions|
+          self.options[:grid_dimensions] = dimensions || "30+10"
+          unless self.options[:grid_dimensions] =~ /^\d+\+\d+$/
+            puts "Please enter your dimensions as <column_width>+<gutter_width>. E.g. 20+5 or 30+10."
+            exit
+          end
+          self.options[:command] = :generate_grid_background
+        end
+
       end
       
       def do_command(command)

lib/compass/grid_builder.rb

@@ -1,3 +1,4 @@
+# This file came from the Blueprint Project
 begin
   require 'rubygems'
   gem 'rmagick'
@@ -5,15 +6,17 @@ begin
 rescue Exception => e
 end
 
-module Blueprint
+module Compass
   # Uses ImageMagick and RMagick to generate grid.png file
   class GridBuilder
+    include Actions
+
     begin
       include Magick
     rescue Exception => e
     end
 
-    attr_reader :column_width, :gutter_width, :output_path, :able_to_generate
+    attr_reader :column_width, :gutter_width, :output_path, :able_to_generate, :options
 
     # ==== Options
     # * <tt>options</tt>
@@ -23,9 +26,14 @@ module Blueprint
     def initialize(options={})
       @able_to_generate = Magick::Long_version rescue false
       return unless @able_to_generate
-      @column_width = options[:column_width] || Blueprint::COLUMN_WIDTH
-      @gutter_width = options[:gutter_width] || Blueprint::GUTTER_WIDTH
-      @output_path  = options[:output_path]  || Blueprint::SOURCE_PATH
+      @column_width = options[:column_width]
+      @gutter_width = options[:gutter_width]
+      @output_path  = options[:output_path]
+      @options = options
+    end
+
+    def working_path
+      options[:working_path]
     end
   
     # generates (overwriting if necessary) grid.png image to be tiled in background
@@ -47,8 +55,18 @@ module Blueprint
         end
       end
 
-      FileUtils.mkdir self.output_path unless File.exists? self.output_path
-      rvg.draw.write(File.join(self.output_path, "grid.png"))
+      filename = File.join(self.output_path, "grid.png")
+      if File.exists?(filename)
+        if options[:force]
+          overwrite = true
+        else
+          msg = "#{filename} already exists. Overwrite with --force."
+          raise Compass::FilesystemConflict.new(msg)
+        end
+      end
+      directory self.output_path
+      logger.record((overwrite ? :overwrite : :create), basename(filename))
+      rvg.draw.write(filename)
     end
   end
 end