Class: Pdfrb::Model::Type::Function

Inherits:
Cos::Dictionary show all
Defined in:
lib/pdfrb/model/type/function.rb

Overview

PDF Function dictionary (s8.9.1). Functions map input values to output values; used by shadings, color spaces, and other computational graphics primitives.

Four function types exist (s8.9.4..7):

* Type 0: Sampled (N-dimensional lookup table)
* Type 2: Exponential (C0 + (C1 - C0) * t^r)
* Type 3: Stitching (concatenation of multiple subfunctions)
* Type 4: PostScript calculator (most flexible)

Direct Known Subclasses

FunctionExponential, FunctionStitching

Instance Attribute Summary

Attributes inherited from Object

#document, #gen, #oid, #value

Instance Method Summary collapse

Methods inherited from Cos::Dictionary

#[], #[]=, arlington_available?, arlington_default, arlington_key_to_symbol, arlington_loaded_for?, arlington_mark_loaded, arlington_object, arlington_one_type_to_ruby, arlington_required?, arlington_types_to_ruby, arlington_version, define_field, define_field_from_arlington, #delete, #each, each_field, #each_raw, #empty?, field, #initialize, #key?, #keys, lookup_type, own_fields, #pdf_type, register_type, type_map, #validate

Methods inherited from Object

#==, define_type, #deref, #indirect?, #initialize, #must_be_indirect?, #pdf_type, pdf_type

Constructor Details

This class inherits a constructor from Pdfrb::Model::Cos::Dictionary

Instance Method Details

#domain ⇒ Object 



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# File 'lib/pdfrb/model/type/function.rb', line 18

def domain; self[:Domain]; end

#exponential? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/pdfrb/model/type/function.rb', line 22

def exponential?; function_type == 2; end

#function_type ⇒ Object 



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# File 'lib/pdfrb/model/type/function.rb', line 16

def function_type; self[:FunctionType]; end

#input_dimension ⇒ Object 



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# File 'lib/pdfrb/model/type/function.rb', line 26

def input_dimension
  return nil unless domain

  arr = domain.is_a?(Pdfrb::Model::PdfArray) ? domain.to_a : domain
  arr.is_a?(Array) ? arr.size / 2 : nil
end

#output_dimension ⇒ Object 



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# File 'lib/pdfrb/model/type/function.rb', line 33

def output_dimension
  return nil unless range

  arr = range.is_a?(Pdfrb::Model::PdfArray) ? range.to_a : range
  arr.is_a?(Array) ? arr.size / 2 : nil
end

#postscript? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/pdfrb/model/type/function.rb', line 24

def postscript?; function_type == 4; end

#range ⇒ Object 



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# File 'lib/pdfrb/model/type/function.rb', line 19

def range; self[:Range]; end

#sampled? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/pdfrb/model/type/function.rb', line 21

def sampled?; function_type.zero?; end

#stitching? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/pdfrb/model/type/function.rb', line 23

def stitching?; function_type == 3; end