This module exposes a few low-level PDF features for those who want to extend Prawn’s core functionality. If you are not comfortable with low level PDF functionality as defined by Adobe’s specification, chances are you won’t need anything you find here.
@private
Appends a raw string to the current page content.
# Raw line drawing example: x1,y1,x2,y2 = 100,500,300,550 pdf.add_content("%.3f %.3f m" % [ x1, y1 ]) # move pdf.add_content("%.3f %.3f l" % [ x2, y2 ]) # draw path pdf.add_content("S") # stroke
# File lib/prawn/document/internals.rb, line 55 def add_content(str) save_graphics_state if graphic_state.nil? state.page.content << str << "\n" end
Defines a block to be called just before the document is rendered.
# File lib/prawn/document/internals.rb, line 76 def before_render(&block) state.before_render_callbacks << block end
At any stage in the object tree an object can be replaced with an indirect reference. To get access to the object safely, regardless of if it’s hidden behind a Prawn::Reference, wrap it in deref().
# File lib/prawn/document/internals.rb, line 43 def deref(obj) obj.is_a?(PDF::Core::Reference) ? obj.data : obj end
The Name dictionary (PDF spec 3.6.3) for this document. It is lazily initialized, so that documents that do not need a name dictionary do not incur the additional overhead.
# File lib/prawn/document/internals.rb, line 64 def names state.store.root.data[:Names] ||= ref!(:Type => :Names) end
Returns true if the Names dictionary is in use for this document.
# File lib/prawn/document/internals.rb, line 70 def names? state.store.root.data[:Names] end
Defines a block to be called just before a new page is started.
# File lib/prawn/document/internals.rb, line 82 def on_page_create(&block) if block_given? state.on_page_create_callback = block else state.on_page_create_callback = nil end end
Creates a new Prawn::Reference and adds it to the Document’s object list. The data argument is anything that Prawn::PdfObject() can convert.
Returns the identifier which points to the reference in the ObjectStore
# File lib/prawn/document/internals.rb, line 23 def ref(data) ref!(data).identifier end
Like ref, but returns the actual reference instead of its identifier.
While you can use this to build up nested references within the object tree, it is recommended to persist only identifiers, and them provide helper methods to look up the actual references in the ObjectStore if needed. If you take this approach, Prawn::Document::Snapshot will probably work with your extension
# File lib/prawn/document/internals.rb, line 35 def ref!(data) state.store.ref(data) end
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