Refactoring for Easier Testing

Author: merbjedi

lib/sprite.rb

@@ -1 +1,21 @@
-require 'sprite/sprite'
+# set up Sprite module
+module Sprite  
+  def self.root
+    @root ||= nil
+
+    # set the root to the framework setting (if not already set)
+    @root ||= begin
+      if defined?(Rails)
+        Rails.root
+      elsif defined?(Merb)
+        Merb.root
+      else
+        "."
+      end
+    end
+    @root
+  end  
+end
+
+require 'sprite/builder'
+require 'sprite/image_combiner'

lib/sprite/builder.rb

@@ -0,0 +1,87 @@
+module Sprite
+  class Builder  
+    DEFAULT_CONFIG_PATH = 'config/sprite.yml'
+    DEFAULT_IMAGE_PATH = 'public/images/'
+    DEFAULT_FILE_PATH = 'tmp/sprite.css'
+    
+    def initialize(settings = nil)
+      @image_path = DEFAULT_IMAGE_PATH
+    
+      if settings.is_a?(Hash)
+        @sprite_config = settings
+      else
+        @sprite_config = read_sprite_config(settings)
+      end
+    end
+  
+    def build
+      @output = {}
+    
+      # build up settings
+      @image_path = sprite_config['config']['base_image_path'] ? Sprite.root+"/"+sprite_config['config']['base_image_path']+"/" : DEFAULT_IMAGE_PATH
+      @file_path = sprite_config['config']['output_file'] ? Sprite.root+"/"+sprite_config['config']['output_file'] : DEFAULT_FILE_PATH
+    
+      # create images
+      sprite_config['images'].each do |configuration|
+         output_image(configuration)
+      end
+    
+      # write css
+      output_css(sprite_config)
+    end
+  
+    def output_image(configuration)
+      results = []
+      sources = configuration['sources'].collect {|source| Dir.glob(@image_path+source)}.flatten
+      dest = configuration['target'] || sources[0].gsub(/\./,"_sprite.")
+      spaced_by = configuration['spaced_by'] || 0
+      dest_image = ImageUtil.get_image(sources.shift)
+      results << ImageUtil.image_properties(dest_image).merge(:x => 0, :y => 0)
+      sources.each do |source|
+        source_image = ImageUtil.get_image(source)
+        if configuration['align'] == 'horizontal'
+          gravity = Magick::EastGravity
+          x = dest_image.columns + spaced_by
+          y = 0
+        else
+          gravity = Magick::SouthGravity
+          x = 0
+          y = dest_image.rows + spaced_by
+        end
+        results << ImageUtil.image_properties(source_image).merge(:x => x, :y => y)
+        dest_image = ImageUtil.composite_images(dest_image, source_image, x, y)
+      end
+      @output[dest] = results
+      dest_image.write(@image_path + dest)
+    end
+  
+    def output_file(configuration)
+      File.open(@file_path, 'w') do |f|
+        @output.each do |dest, results|
+          results.each do |result|
+            f.puts ".#{result[:name]}"
+            f.puts "  background: url(http://github.com/'/images/%3Cspan%20class=pl-s1%3E%3Cspan%20class=pl-kos%3E#{%3C/span%3E%3Cspan%20class=pl-s1%3Edest%3C/span%3E%3Cspan%20class=pl-kos%3E}%3C/span%3E%3C/span%3E') no-repeat #{result[:x]}px #{result[:y]}px;"
+            f.puts "  width: #{result[:width]}px;"
+            f.puts "  height: #{result[:height]}px;"
+            f.puts ""
+          end
+        end
+      end
+    end
+
+    protected
+  
+    # reads config settings from the given path
+    def read_sprite_config(path = nil)
+      config_path = File.join(Sprite.root, path || DEFAULT_CONFIG_PATH)
+      begin
+        config = File.open(config_path) {|f| YAML::load(f)}    
+      rescue => e
+        puts "Unable to read sprite config: #{Sprite.root+"/"+config_path}"
+        puts e.to_s
+      end
+      config
+    rescue
+    end
+  end
+end

lib/sprite/image_combiner.rb

@@ -0,0 +1,30 @@
+module Sprite
+  class ImageCombiner
+    def initialize
+      # avoid loading rmagick till the last possible moment
+      require 'rmagick'
+    end
+    
+    def composite_images(dest_image, src_image, x, y)
+      width = [src_image.columns + x, dest_image.columns].max
+      height = [src_image.rows + y, dest_image.rows].max
+      image = Magick::Image.new(width, height)
+      image.opacity = Magick::MaxRGB
+
+      image.composite!(dest_image, 0, 0, Magick::OverCompositeOp)
+      image.composite!(src_image, x, y, Magick::OverCompositeOp)
+      image
+    end
+
+
+    # Image Utility Methods
+    def get_image(image_filename)
+      image = Magick::Image::read(image_filename).first
+    end
+
+    def image_properties(image)
+      {:name => File.basename(image.filename).split('.')[0], :width => image.columns, :height => image.rows}
+    end
+
+  end
+end

lib/sprite/sprite.rb

@@ -2,5 +2,9 @@
 require 'spec/autorun'
 require 'date'
 
-RAILS_ROOT = '.'
-require File.join(File.dirname(__FILE__), '/../lib/sprite.rb')
+$LOAD_PATH.unshift(File.join(File.dirname(__FILE__), "/../lib"))
+
+require 'sprite'
+
+# set Sprite.root to be this spec/ folder
+Sprite.module_eval{ @root = File.dirname(__FILE__) }

spec/resources/configs/config1.yml

@@ -0,0 +1,44 @@
+require File.dirname(__FILE__) + '/../spec_helper'
+
+describe Sprite do
+  before(:all) do
+    # build a sprite object with empty config
+    @combiner = Sprite::ImageCombiner.new
+    
+    @image_paths = {
+      :good_topic => "#{Sprite.root}/resources/images/topics/good_topic.gif",
+      :mid_topic => "#{Sprite.root}/resources/images/topics/mid_topic.gif"
+    }
+  end
+  
+  context "image handling" do
+    context "get_image" do
+      it "should get a image" do
+        @combiner.get_image(@image_paths[:good_topic]).class.should == Magick::Image
+      end
+    end
+  
+    context "image_properties" do
+      it "should get image properties" do
+        image = @combiner.get_image(@image_paths[:good_topic])
+        @combiner.image_properties(image).should == {:name => 'good_topic', :width => 20, :height => 19}
+      end
+    end
+  
+    context "composite_images" do
+      it "should composite two images into one horizontally" do
+        image1 = @combiner.get_image(@image_paths[:good_topic])
+        image2 = @combiner.get_image(@image_paths[:mid_topic])
+        image = @combiner.composite_images(image1, image2, image1.columns, 0)
+        @combiner.image_properties(image).should == {:name => nil, :width => 40, :height => 19}
+      end
+    
+      it "should composite two images into one verically" do
+        image1 = @combiner.get_image(@image_paths[:good_topic])
+        image2 = @combiner.get_image(@image_paths[:mid_topic])
+        image = @combiner.composite_images(image1, image2, 0, image1.rows)
+        @combiner.image_properties(image).should == {:name => nil, :width => 20, :height => 38}
+      end
+    end
+  end
+end

spec/resources/good_topic.gif renamed to spec/resources/images/topics/good_topic.gif

@@ -0,0 +1,12 @@
+require File.dirname(__FILE__) + '/../spec_helper.rb'
+
+describe Sprite do
+
+  context "Verify Settings" do
+    before(:all) do
+      @sprite = Sprite.new
+    end
+  end
+  
+  
+end

spec/resources/mid_topic.gif renamed to spec/resources/images/topics/mid_topic.gif

@@ -1,7 +1,13 @@
+require File.join(File.dirname(__FILE__), '../lib/sprite/sprite.rb')
+
 namespace :sprite do  
   desc "build sprite images based on config/sprite.yml"
   task :build do
-    require File.join(File.dirname(__FILE__), '../lib/sprite/sprite.rb')
     Sprite.new.build
   end
+  
+  task :list => [:build] do
+    # TODO
+    # list all the currently configured sprites
+  end
 end