public= directory.

     # File lib/image_bundle_helper.rb, line 123
123:   def image_bundle(css_class = nil, sprite_type = :png, content_target = :head, replacement_image = '/images/clear.gif', *args, &block)
124:     # Bind buffer to the ERB output buffer of the templates.
125:     buffer = eval("_erbout", block.binding)
126: 
127:     # Mark the current position in the buffer
128:     pos = buffer.length
129: 
130:     # Render the block contained within the image_bundle tag. The
131:     # rendered output is appended to buffer.
132:     block.call(*args)
133: 
134:     # Extract the output produced by the block.
135:     block_output = buffer[pos..-1]
136:     buffer[pos..-1] = ''
137: 
138:     # Replace the img tags in the output with links to clear.gif and
139:     # styling to use the master image created from the individual
140:     # images.
141:     images = Hash.new
142:     re = (css_class == nil) ? /(<img\s*)([^>]*?)(\s*\/?>)/im : /(<img\s*)([^>]*?class\s*=\s*["']?[^"']*?#{css_class}[^"']*?["']?[^>]*?)(\s*\/?>)/im
143:     block_rewrite = ''
144:     while pos = (block_output =~ re) do
145: 
146:       # Store match data for later reference.
147:       img_match = $~.to_s
148:       img_tag = $1
149:       attributes = $2
150:       img_closing_tag = $3
151: 
152:       # Remember where to continue searching from in the next
153:       # iteration.
154:       continue_pos = pos+img_match.length
155: 
156:       # Write out the content before the start of the tag
157:       block_rewrite << block_output[0..pos-1]
158:       if img_match =~ /src\=["']?https?:\/\//i then
159:         block_rewrite << img_match
160:       else
161: 
162:         # Write out the opening portion of the image tag (<img).
163:         block_rewrite << img_tag
164: 
165:         # Process all attributes of the img tag.
166:         height_given = width_given = nil
167:         classes = ''
168:         ping = ::ImageBundleHelper::Image.new
169:         while pos = (attributes =~ /([^ =]+?)\s*=\s*(("?([^"=]*?)")|('?([^'=]*?)'))/im) do
170:           attribute = $1
171:           value = $4 || $6
172:           attr_continue_pos = pos+$~.to_s.length
173:           case attribute
174:           when 'src'
175:             ping.path = value
176:             # Read only the image's meta data not its image content.
177:             ping.file = "#{RAILS_ROOT}/public#{ping.path}"
178:             image = ::Magick::Image.ping(ping.file)[0]
179:             ping.height = image.rows
180:             ping.width = image.columns
181:             block_rewrite << "#{attribute}=\"#{replacement_image}\" "
182:           when 'height'
183:             height_given = value.to_i
184:           when 'width'
185:             width_given = value.to_i
186:           when 'class'
187: 
188:             # Prepend a space for later concatenation with bndl class.
189:             classes = " #{value}"
190:           else
191: 
192:             # Pass through all other attributes
193:             block_rewrite << "#{attribute}=\"#{value}\" "
194:           end
195:           attributes = attributes[attr_continue_pos..-1]
196:         end
197: 
198:         # Calculate the height and width of the image based on the
199:         # specified height/width and the source file's height and
200:         # width. Scaling needs to happen when the sprite is created
201:         if height_given == nil then
202:           if width_given != nil then
203:             ping.height = (ping.height * (width_given.to_f / ping.width.to_f)).to_i
204:             ping.width = width_given
205:           end
206:         else
207:           if width_given == nil then
208:             ping.width = (ping.width * (height_given.to_f / ping.height.to_f)).to_i
209:             ping.height = height_given
210:           else
211:             ping.width = width_given
212:             ping.height = height_given
213:           end
214:         end
215: 
216:         # Only add unique images and height/width combinations to the hash.
217:         key = "bndl#{::Digest::MD5.hexdigest("#{ping.path}:#{ping.height}:#{ping.width}").hash}"
218:         images[key] ||= ping
219:         block_rewrite << "class =\"#{key}#{classes}\" "
220:         block_rewrite << "height=\"#{ping.height}\" "
221:         block_rewrite << "width=\"#{ping.width}\" "
222:         block_rewrite << img_closing_tag
223:       end
224:       block_output = block_output[continue_pos..-1]
225:     end
226: 
227:     # Create a sprite when there are source files and if it doesn't
228:     # already exists.
229:     if images.length > 0 then
230:       sprite_path = '/' + SPRITE_BASE_DIR + '/' + ::Digest::MD5.hexdigest(images.keys.inject do |concat_names, key| concat_names + '|' + key end) + ".#{sprite_type}"
231:       sprite_file = "#{RAILS_ROOT}/public/#{sprite_path}"
232:       if !File.exists?(sprite_file) then
233: 
234:         # Stack scaled source images left to right.
235:         sprite = images.values.inject(::Magick::ImageList.new) do |image_list, ping|
236:           image_list << ::Magick::ImageList.new(ping.file)[0].scale(ping.width, ping.height)
237:         end.append(false)
238:         sprite.write(sprite_file)
239:       end
240: 
241:       # Construct style tag to be included in the header.
242:       current_y = 0
243:       bundle_styles = "\n<style type=\"text/css\">\n"
244:       bundle_styles << images.keys.inject('') do |styles, key|
245:         images[key].x_pos = current_y
246:         current_y += images[key].width
247:         styles + ".#{key} {\n   background-image:url(#{sprite_path});\n background-position: -#{images[key].x_pos}px 0px;\n}\n"
248:       end
249:       bundle_styles << "</style>\n"
250:     end
251: 
252:     # Write the remaining block output that follows the last img tag.
253:     block_rewrite << block_output
254:     buffer << block_rewrite if block_rewrite
255:     content_for content_target.to_sym, bundle_styles ||= ''
256:   end