Add support for rendering with layout

README

@@ -6,7 +6,130 @@ for generating pdf files leveraging the new kick-ass prawn library
 
 full documentation/demos at: http://cracklabs.com/prawnto
 
+Copyright (c) 2008 cracklabs.com, released under the MIT license
 
 
+Forked prawnto
+==============
 
-Copyright (c) 2008 cracklabs.com, released under the MIT license
+Ever wanted to use layouts for PDF's ? Here it is!
+
+Note that it is targeted to Rails 2.3.x, a Rails 3.x branch may be created in the future.
+
+The first change was to remove prawn_xxx template handler, it contained too much specific magic.
+If you had some template for it, read on and convert your templates.
+
+Usage
+=====
+
+Without layout
+--------------
+
+Your templates are either .prawn or .prawn_dsl at the moment, and you don't have to change anything to make them
+work with this new plugin. This is because you are not using layouts.
+
+With layout
+-----------
+
+Simply define a layout in views/layouts with some code and at least one yield statement:
+
+		# invoices.pdf.prawn_dsl
+
+		header_height = 2.5.cm
+		footer_height = 1.cm
+
+		repeat :all do
+		  mask :fill_color, :line_width, :stroke_color do
+		    fill_color "000000"
+		    stroke_color '000000'
+		    line_width(1)
+
+		    # header
+		    bounding_box [bounds.left, bounds.top], :width  => bounds.width, :height => header_height-3.mm-5.mm do
+		      image "#{Rails.root}/public/images/logo.jpg", :fit => [5.cm, 1.6.cm], :at => [bounds.left,bounds.top]
+
+          text @title.to_s, :align => :center, :size => 20 if @title
+
+					# action template may put some additional header stuff
+					yield :header
+
+		      stroke_horizontal_line bounds.left,bounds.right, :at => bounds.bottom - 3.mm
+		    end
+
+		    # footer
+		    stroke_horizontal_line bounds.left,bounds.right, :at => bounds.bottom + footer_height - 5.mm
+		  end
+		end
+
+		bounding_box [bounds.left, bounds.top - header_height], :width  => bounds.width, :height => bounds.height-(header_height+footer_height) do
+			# action rendering comes here!
+		  yield
+		end
+
+		# put page numbers now that all pages are generated
+		page_count.times do |i|
+		  go_to_page(i+1)
+		  mask :fill_color, :line_width, :stroke_color do
+		    fill_color "000000"
+		    stroke_color '000000'
+		    line_width(1)
+
+		    caption = "#{i+1} / #{page_count}"
+		    draw_text caption, :size => 12, :at => [bounds.left + (bounds.width - width_of(caption)) / 2, bounds.bottom]
+		  end
+		end
+
+Then in an action template
+
+    # show.prawn.dsl
+
+		# This code is run before the layout so you may setup some variables that will be used in the layout
+		@title = "Invoice of #{@invoice.date}"
+
+		# This is required to postpone the action "rendering" within the layout
+		content_for do |pdf|
+			# put some text
+			pdf.text @invoice.title
+
+			# do like .prawn_dsl
+			view = self
+			pdf.instance_eval do
+				# you can call direct pdf methods here
+				text "Waoow"
+
+				# access view instance variable like this (which comes from the controller @invoice)
+				text view[:invoice].customer.name
+
+				# render a partial (ask the view to do it)
+				view.render :partial => 'link', :object => 'A link'
+			end
+
+			# render a partial
+			render :partial => 'link', :collection => @links
+		end
+
+For the sake of completeness, here is the partial
+
+		# _links.pdf.prawn_dsl
+
+		text link
+
+You may use #content_for and corresponding yield anywhere you want. It follows the same behaviour
+than in ERB like templates.
+
+
+Internals
+=========
+
+The way layout works in Rails is targeted for text template generation. With prawn we use code template
+generation, I mean each layout doesn't produce any output (like in ERB) it is simply run at a specific
+time with a specific object (pdf). The output is generated by calling pdf.render just before sending it
+as the request response (not on your template, backed in the plugin).
+
+So, the action template is run FIRST, then the layout template. This is exactly the opposite way for
+code template as the layout should run first (setup page, put some header or footer, etc...).
+This is the reason for this call to content_for in the action template when using a layout (see doc above).
+This is also the reason for the patch to #content_for and Template class.
+
+
+Copyright (c) 2011 Pascal Hurni, released under the MIT license

init.rb

@@ -3,5 +3,4 @@
 Mime::Type.register "application/pdf", :pdf
 ActionView::Template.register_template_handler 'prawn', Prawnto::TemplateHandlers::Base
 ActionView::Template.register_template_handler 'prawn_dsl', Prawnto::TemplateHandlers::Dsl
-ActionView::Template.register_template_handler 'prawn_xxx', Prawnto::TemplateHandlers::Raw  
 

lib/prawnto.rb

@@ -28,5 +28,6 @@ class ActionView::Base
   include Prawnto::ActionView
 end
 
-
-
+class ActionView::Template
+  include Prawnto::Template
+end

lib/prawnto/action_view.rb

@@ -1,12 +1,87 @@
 module Prawnto
+  # Acts like a dummy string to let ActionView concat to it
+  class NullObject
+    def <<(any)
+    end
+  end
+
   module ActionView
 
+    def self.included(base)
+      base.alias_method_chain :render, :prawnto
+    end
+
+    def render_with_prawnto(options = {}, local_assigns = {}, &block) #:nodoc:
+      local_assigns ||= {}
+
+      if template_format == :pdf && @pdf.nil?
+        # Override some helpers and add our own
+        extend PrawntoLayoutHelpers
+
+        # Mimic a text like template so that #concat can be called by ActionView when rendering layouts with code blocks
+        @output_buffer = NullObject.new
+
+        _prawnto_compile_setup
+        @pdf = Prawn::Document.new(@prawnto_options[:prawn])
+        render_without_prawnto(options, local_assigns, &block)
+        @pdf.render
+      else
+        render_without_prawnto(options, local_assigns, &block)
+      end
+    end
+
   private
     def _prawnto_compile_setup(dsl_setup = false)
       compile_support = Prawnto::TemplateHandler::CompileSupport.new(controller)
       @prawnto_options = compile_support.options
     end
+
+    module PrawntoLayoutHelpers
+      def content_for(name = :_action, &block)
+        instance_variable_set("@content_for_#{name}", block)
+        nil
+      end
+
+      def [](var)
+        instance_variable_get(:"@#{var}")
+      end
+    end
 
   end
 end
 
+module Prawnto
+  module Template
+    def self.included(base)
+      base.alias_method_chain :initialize, :prawnto
+    end
+
+    def initialize_with_prawnto(*args)
+      initialize_without_prawnto(*args)
+      if format.to_s == 'pdf'
+        extend InstanceMethods
+      end
+    end
+
+    module InstanceMethods
+      def render(view, local_assigns = {})
+        compile(local_assigns)
+
+        view.with_template self do
+          view.send(:_evaluate_assigns_and_ivars)
+          view.send(:_set_controller_content_type, mime_type) if respond_to?(:mime_type)
+
+          view.send(method_name(local_assigns), local_assigns) do |*names|
+            ivar = :@_proc_for_layout
+            if view.instance_variable_defined?(ivar) && (proc = view.instance_variable_get(ivar))
+              proc.call(*names)
+            elsif view.instance_variable_defined?(ivar = :"@content_for_#{names.first || :_action}")
+              view.instance_variable_get(ivar).call(view.instance_variable_get(:@pdf))
+            end
+          end
+        end
+      end
+    end
+
+  end
+end

lib/prawnto/template_handler/compile_support.rb

@@ -29,28 +29,14 @@ def ie_request?
       end
       memoize :ie_request?
 
-      # added to make ie happy with ssl pdf's (per naisayer)
-      def ssl_request?
-        @controller.request.env['SERVER_PROTOCOL'].downcase == "https"
-      end
-      memoize :ssl_request?
-
       # TODO: kept around from railspdf-- maybe not needed anymore? should check.
       def set_pragma
-        if ssl_request? && ie_request?
-          @controller.headers['Pragma'] = 'public' # added to make ie ssl pdfs work (per naisayer)
-        else
-          @controller.headers['Pragma'] ||= ie_request? ? 'no-cache' : ''
-        end
+        @controller.headers['Pragma'] ||= ie_request? ? 'no-cache' : ''
       end
 
       # TODO: kept around from railspdf-- maybe not needed anymore? should check.
       def set_cache_control
-        if ssl_request? && ie_request?
-          @controller.headers['Cache-Control'] = 'maxage=1' # added to make ie ssl pdfs work (per naisayer)
-        else
-          @controller.headers['Cache-Control'] ||= ie_request? ? 'no-cache, must-revalidate' : ''
-        end
+        @controller.headers['Cache-Control'] ||= ie_request? ? 'no-cache, must-revalidate' : ''
       end
 
       def set_content_type

lib/prawnto/template_handlers/base.rb

@@ -4,10 +4,7 @@ class Base < ::ActionView::TemplateHandler
       include ::ActionView::TemplateHandlers::Compilable
 
       def compile(template)
-        "_prawnto_compile_setup;" +
-        "pdf = Prawn::Document.new(@prawnto_options[:prawn]);" + 
-        "#{template.source}\n" +
-        "pdf.render;"
+        "pdf = @pdf; #{template.source}"
       end
     end
   end

lib/prawnto/template_handlers/dsl.rb

@@ -3,10 +3,7 @@ module TemplateHandlers
     class Dsl < Base
 
       def compile(template)
-        "_prawnto_compile_setup(true);" +
-        "pdf = Prawn::Document.new(@prawnto_options[:prawn]);" + 
-        "pdf.instance_eval do; #{template.source}\nend;" +
-        "pdf.render;"
+        "view = self; @pdf.instance_eval do; #{template.source}\nend;"
       end
 
     end