Module: Prawn::Document::Internals
- Included in:
- Prawn::Document
- Defined in:
- lib/prawn/document/internals.rb
Overview
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.
Instance Method Summary collapse
-
#add_content(str) ⇒ Object
Appends a raw string to the current page content.
-
#before_render(&block) ⇒ Object
Defines a block to be called just before the document is rendered.
-
#deref(obj) ⇒ Object
At any stage in the object tree an object can be replaced with an indirect reference.
-
#names ⇒ Object
The Name dictionary (PDF spec 3.6.3) for this document.
-
#names? ⇒ Boolean
Returns true if the Names dictionary is in use for this document.
-
#on_page_create(&block) ⇒ Object
Defines a block to be called just before a new page is started.
-
#ref(data) ⇒ Object
Creates a new Prawn::Reference and adds it to the Document’s object list.
-
#ref!(data) ⇒ Object
Like ref, but returns the actual reference instead of its identifier.
Instance Method Details
#add_content(str) ⇒ Object
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
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# File 'lib/prawn/document/internals.rb', line 56 def add_content(str) save_graphics_state if graphic_state.nil? state.page.content << str << "\n" end |
#before_render(&block) ⇒ Object
Defines a block to be called just before the document is rendered.
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# File 'lib/prawn/document/internals.rb', line 77 def before_render(&block) state.before_render_callbacks << block end |
#deref(obj) ⇒ Object
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().
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# File 'lib/prawn/document/internals.rb', line 44 def deref(obj) obj.is_a?(Prawn::Core::Reference) ? obj.data : obj end |
#names ⇒ Object
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.
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# File 'lib/prawn/document/internals.rb', line 65 def names state.store.root.data[:Names] ||= ref!(:Type => :Names) end |
#names? ⇒ Boolean
Returns true if the Names dictionary is in use for this document.
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# File 'lib/prawn/document/internals.rb', line 71 def names? state.store.root.data[:Names] end |
#on_page_create(&block) ⇒ Object
Defines a block to be called just before a new page is started.
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# File 'lib/prawn/document/internals.rb', line 83 def on_page_create(&block) if block_given? state.on_page_create_callback = block else state.on_page_create_callback = nil end end |
#ref(data) ⇒ Object
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
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# File 'lib/prawn/document/internals.rb', line 24 def ref(data) ref!(data).identifier end |
#ref!(data) ⇒ Object
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
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# File 'lib/prawn/document/internals.rb', line 36 def ref!(data) state.store.ref(data) end |