module Prawn::Stamp
The Prawn::Stamp
module is used to create content that will be included multiple times in a document. Using a stamp has three advantages over creating content anew each time it is placed on the page:
i. faster document creation ii. smaller final document iii. faster display on subsequent displays of the repeated element because the viewer application can cache the rendered results
Example:
pdf.create_stamp("my_stamp") { pdf.fill_circle_at([10, 15], :radius => 5) pdf.draw_text("hello world", :at => [20, 10]) } pdf.stamp("my_stamp")
Public Instance Methods
create_stamp(name, &block)
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Creates a re-usable stamp named name
raises Prawn::Errors::NameTaken
if a stamp already exists in this document with this name raises Prawn::Errors::InvalidName
if name.empty?
Example:
pdf.create_stamp("my_stamp") { pdf.fill_circle_at([10, 15], :radius => 5) pdf.draw_text("hello world", :at => [20, 10]) }
# File lib/prawn/stamp.rb, line 78 def create_stamp(name, &block) dictionary = create_stamp_dictionary(name) page.stamp_stream(dictionary, &block) end
stamp(name)
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Renders the stamp named name
to the page raises Prawn::Errors::InvalidName
if name.empty? raises Prawn::Errors::UndefinedObjectName
if no stamp has been created with this name
Example:
pdf.create_stamp("my_stamp") { pdf.fill_circle_at([10, 15], :radius => 5) pdf.text("hello world", :at => [20, 10]) } pdf.stamp("my_stamp")
# File lib/prawn/stamp.rb, line 43 def stamp(name) dictionary_name, dictionary = stamp_dictionary(name) add_content "/#{dictionary_name} Do" page.xobjects.merge!(dictionary_name => dictionary) end
stamp_at(name, point)
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Renders the stamp named name
at a position offset from the initial coords at which the elements of the stamp was created
Example:
pdf.create_stamp("circle") do pdf.fill_circle_at([0, 0], :radius => 25) end # draws a circle at 100, 100 pdf.stamp_at("circle", [100, 100])
See stamp() for exceptions that might be raised
# File lib/prawn/stamp.rb, line 62 def stamp_at(name, point) translate(point[0], point[1]) { stamp(name) } end
Private Instance Methods
create_stamp_dictionary(name)
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# File lib/prawn/stamp.rb, line 107 def create_stamp_dictionary(name) raise Prawn::Errors::InvalidName if name.empty? raise Prawn::Errors::NameTaken unless stamp_dictionary_registry[name].nil? # BBox origin is the lower left margin of the page, so we need # it to be the full dimension of the page, or else things that # should appear near the top or right margin are invisible dictionary = ref!(:Type => :XObject, :Subtype => :Form, :BBox => [0, 0, page.dimensions[2], page.dimensions[3]]) dictionary_name = "Stamp#{next_stamp_dictionary_id}" stamp_dictionary_registry[name] = { :stamp_dictionary_name => dictionary_name, :stamp_dictionary => dictionary } dictionary end
next_stamp_dictionary_id()
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# File lib/prawn/stamp.rb, line 90 def next_stamp_dictionary_id stamp_dictionary_registry.length + 1 end
stamp_dictionary(name)
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# File lib/prawn/stamp.rb, line 94 def stamp_dictionary(name) raise Prawn::Errors::InvalidName if name.empty? if stamp_dictionary_registry[name].nil? raise Prawn::Errors::UndefinedObjectName end dict = stamp_dictionary_registry[name] dictionary_name = dict[:stamp_dictionary_name] dictionary = dict[:stamp_dictionary] [dictionary_name, dictionary] end
stamp_dictionary_registry()
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# File lib/prawn/stamp.rb, line 86 def stamp_dictionary_registry @stamp_dictionary_registry ||= {} end