def transparent(opacity, stroke_opacity=opacity, &block)
min_version(1.4)
key = "#{opacity}_#{stroke_opacity}"
if opacity_dictionary_registry[key]
opacity_dictionary = opacity_dictionary_registry[key][:obj]
opacity_dictionary_name = opacity_dictionary_registry[key][:name]
else
opacity_dictionary = ref!(:Type => :ExtGState,
:CA => stroke_opacity,
:ca => opacity
)
opacity_dictionary_name = "Tr#{next_opacity_dictionary_id}"
opacity_dictionary_registry[key] = { :name => opacity_dictionary_name,
:obj => opacity_dictionary }
end
page_ext_gstates.merge!(opacity_dictionary_name => opacity_dictionary)
add_content "q"
add_content "/#{opacity_dictionary_name} gs"
yield if block_given?
add_content "Q"
end