specs/data/form_xobject.pdf @@ -1,3 +1,8 @@ +v0.7.7 (XXX) +- Trigger callbacks contained in Form XObjects when we encounter them in a + content stream +- Fix inheritance of page resources to comply with section 3.6.2 + v0.7.6 (28th August 2009) - Various bug fixes that increase the files we can successfully parse - Treat float and integer tokens differently (thanks Neil) CHANGELOG @@ -147,18 +147,14 @@ class PDF::Reader # - metadata # - xml_metadata # - page_count + # - begin_form_xobject + # - end_form_xobject # # == Resource Callbacks # - # Each page and page_container can contain a range of resources required for the page, + # Each page can contain (or inherit) a range of resources required for the page, # including things like fonts and images. The following callbacks may appear - # after begin_page_container and begin_page if the relevant resources exist - # on a page: - # - # In most cases, these callbacks associate a name with each resource, allowing it - # to be referred to by name in the page content. For example, an XObject can hold an image. - # If it gets mapped to the name "IM1", then it can be placed on the page using - # invoke_xobject "IM1". + # after begin_page if the relevant resources exist on a page: # # - resource_procset # - resource_xobject @@ -166,6 +162,12 @@ class PDF::Reader # - resource_colorspace # - resource_pattern # - resource_font + # + # In most cases, these callbacks associate a name with each resource, allowing it + # to be referred to by name in the page content. For example, an XObject can hold an image. + # If it gets mapped to the name "IM1", then it can be placed on the page using + # invoke_xobject "IM1". + # class Content OPERATORS = { 'b' => :close_fill_stroke, @@ -284,22 +286,19 @@ class PDF::Reader # its content def walk_pages (page) - if page[:Resources] - res = page[:Resources] - page.delete(:Resources) - end - # extract page content if page[:Type] == :Pages callback(:begin_page_container, [page]) - walk_resources(@xref.object(res)) if res + res = @xref.object(page[:Resources]) + resources.push res if res @xref.object(page[:Kids]).each {|child| walk_pages(@xref.object(child))} + resources.pop if res callback(:end_page_container) elsif page[:Type] == :Page callback(:begin_page, [page]) - walk_resources(@xref.object(res)) if res - @page = page - @params = [] + res = @xref.object(page[:Resources]) + resources.push res if res + walk_resources(current_resources) if @xref.object(page[:Contents]).kind_of?(Array) contents = @xref.object(page[:Contents]) @@ -312,10 +311,38 @@ class PDF::Reader content_stream(obj) end if page.has_key?(:Contents) and page[:Contents] + resources.pop if res callback(:end_page) end end ################################################################################ + # Retreive the XObject for the supplied label and if it's a Form, walk it + # like a regular page content stream. + # + def walk_xobject_form(label) + xobjects = current_resources[:XObject] || {} + xobject = @xref.object(xobjects[label]) + + if xobject && xobject.hash[:Subtype] == :Form + callback(:begin_form_xobject) + resources = @xref.object(xobject.hash[:Resources]) + walk_resources(resources) if resources + content_stream(xobject.to_s) + callback(:end_form_xobject) + end + end + + ################################################################################ + # Return a merged hash of all resources that are current. Pages, page and xobject + # + def current_resources + hash = {} + resources.each do |res| + hash.merge!(res) + end + hash + end + ################################################################################ # Reads a PDF content stream and calls all the appropriate callback methods for the operators # it contains def content_stream (instructions) @@ -341,8 +368,16 @@ class PDF::Reader # read the raw image data from the buffer without tokenising @params << @buffer.read_until("EI") end + callback(OPERATORS[token], @params) - @params.clear + + if OPERATORS[token] == :invoke_xobject + xobject_label = @params.first + @params.clear + walk_xobject_form(xobject_label) + else + @params.clear + end else @params << token end @@ -352,6 +387,8 @@ class PDF::Reader end ################################################################################ def walk_resources(resources) + return unless resources.respond_to?(:[]) + resources = resolve_references(resources) # extract any procset information @@ -446,6 +483,9 @@ class PDF::Reader obj end end + def resources + @resources ||= [] + end end ################################################################################ end lib/pdf/reader/content.rb @@ -174,4 +174,14 @@ context "PDF::Reader" do receiver.content.size.should eql(1) receiver.content[0][0,7].should eql("WORKING") end + + specify "should correctly process a PDF that uses Form XObjects to repeat content" do + receiver = PageTextReceiver.new + PDF::Reader.file(File.dirname(__FILE__) + "/data/form_xobject.pdf", receiver) + + # confirm the text appears on the correct pages + receiver.content.size.should eql(2) + receiver.content[0].should eql("James Healy") + receiver.content[1].should eql("James Healy") + end end specs/meta_spec.rb 81f2812962b0e8078e867d3948cf10c27bf88474 James Healy jimmy@deefa.com http://github.com/yob/pdf-reader/commit/5d4ed95b36470472dbb90959fc0b14cc316a2891 5d4ed95b36470472dbb90959fc0b14cc316a2891 2009-09-11T00:45:42-07:00 2009-09-11T00:40:33-07:00 trigger Form XObject callbacks inline - Form XObjects are used to place repeated elements in multiple paces in a document. The repeated content is only stored once, so there's a space saving - They're also used to draw Bates numbers on a page - when a Form XObject is encountered in a content stream, trigger all the callbacks it contains, wrapped in :start_form_xobject and :end_form_object callbacks. 38b37240526446c1ee28f0d54cd89130b6a2b34b James Healy jimmy@deefa.com