Class: PhotoUtils::Format

Inherits:
Object
  • Object
show all
Defined in:
lib/photo_utils/formats.rb

Constant Summary collapse

FormatDescriptions =

name height width aliases

%q{
  1/6                         2.4   1.8
  1/4                         2.7   3.6
  1/3.6                       3     4
  1/3.2                       3.42  4.54
  1/3                         3.6   4.8
  1/2.7                       4.04  5.37
  1/2.5                       4.29  5.76
  1/2                         4.8   6.4
  1/1.8                       5.32  7.18
  1/1.7                       5.7   7.6     Canon PowerShot G9, Canon PowerShot G10
  1/1.6                       6.01  8.08
  2/3                         9.6   12.8
  1                           9.6   12.8
  4/3                         13    17.3

  APS-C                       14.8  22.2    Canon EOS DIGITAL REBEL XT, Canon EOS DIGITAL REBEL XTi, Canon EOS DIGITAL REBEL XSi, Canon EOS 450D
  APS-H                       19.1  28.7
  R-D1                        15.6  23.7    Epson R-D1, Epson R-D1s, Epson R-D1g, Epson R-D1x

  DX                          15.5  23.6    NIKON D70

  Leica S2                    30    45

  35                          24    36      FF, Canon EOS 5D

  6x4.5                       56   42      645
  6x4.5 short                 56   40.5
  6x4.5 Mamiya RB/RZ67        56   41.5
  6x6                         56    56
  6x6 short                   56   54
  6x7                         56   72
  6x7 short                   56   69.5
  6x7 Mamiya RB/RZ67          56    69.5
  6x7 Toyo                    56    67
  6x7 Horseman                56    68
  6x7 Pentax                  55    70
  6x7 Cambo-Sinar-Wista       56   70
  6x7 Linhof Super Rollex     56   72
  6x7 Linhof Rapid Rollex     57   76
  6x8                         56   76
  6x9                         56   84
  6x9 23 Graphic              56    83
  6x9 Cambo-Horseman-Wista    56   82
  6x9 Toyo                    56    84
  6x9 Linhof                  56    85
  6x9 Sinar                   57   88
  6x10                        56    92
  6x12                        56    112
  6x12 Linhof                 57   120
  6x17                        56    168
  6x17                        56    168

  Polaroid 660                73    95
  Polaroid 660 on Mamiya RB/RZ67    73    73

  Polaroid 550                92    126
  Polaroid 545                95    122
  4x5 Quickload               95   120
  4x5 Fidelity                97    120     4x5

  5x7                         127   178

  8x10                        203   254
}

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(params = {}) ⇒ Format

Returns a new instance of Format.



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# File 'lib/photo_utils/formats.rb', line 104

def initialize(params={})
  params.each { |k, v| send("#{k}=", v) }
end

Instance Attribute Details

#frame ⇒ Object

Returns the value of attribute frame.



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# File 'lib/photo_utils/formats.rb', line 102

def frame
  @frame
end

#name ⇒ Object

Returns the value of attribute name.



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# File 'lib/photo_utils/formats.rb', line 101

def name
  @name
end

Class Method Details

.[](name) ⇒ Object 



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# File 'lib/photo_utils/formats.rb', line 96

def self.[](name)
  load_formats unless class_variable_defined?('@@formats')
  @@formats[name]
end

.load_formats ⇒ Object 



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# File 'lib/photo_utils/formats.rb', line 78

def self.load_formats
  @@formats = {}
  FormatDescriptions.split("\n").each do |line|
    case line.sub(/#.*/, '').strip
    when /^(.*?)\s{2,}([\d\.]+)\s+([\d\.]+)\s*(.*?)$/
      name, height, width, aliases = $1, $2, $3, $4
      frame = Frame.new(width.to_f, height.to_f)
      format = Format.new(name: name, frame: frame)
      @@formats[name] = format
      aliases.split(/,\s*/).each { |a| @@formats[a] = format }
    when ''
      # ignore blank line
    else
      raise "Can't parse format line: #{line.inspect}"
    end
  end
end

Instance Method Details

#angle_of_view(focal_length) ⇒ Object 



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# File 'lib/photo_utils/formats.rb', line 130

def angle_of_view(focal_length)
  # http://imaginatorium.org/stuff/angle.htm
  # http://en.wikipedia.org/wiki/Angle_of_view
  a = Math.arcdeg(2 * Math.atan(@frame.diagonal / (2 * focal_length)))
  Angle.new(a)
end

#crop_factor(reference = ) ⇒ Object 



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# File 'lib/photo_utils/formats.rb', line 125

def crop_factor(reference=Format['35'])
  # http://en.wikipedia.org/wiki/Crop_factor
  reference.frame.diagonal / @frame.diagonal
end

#field_of_view(focal_length, subject_distance) ⇒ Object 



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# File 'lib/photo_utils/formats.rb', line 137

def field_of_view(focal_length, subject_distance)
  # http://en.wikipedia.org/wiki/Field_of_view
  Frame.new(
    subject_distance * (@frame.height / focal_length),
    subject_distance * (@frame.width  / focal_length))
end

#focal_length_equivalent(focal_length, other = ) ⇒ Object 



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# File 'lib/photo_utils/formats.rb', line 120

def focal_length_equivalent(focal_length, other=Format['35'])
  f = focal_length * crop_factor(other)
  Length.new(f)
end

#inspect ⇒ Object 



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# File 'lib/photo_utils/formats.rb', line 108

def inspect
  "<#{self.class} name=#{@name.inspect} frame=#{@frame.inspect}>"
end

#to_s(short = true) ⇒ Object 



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# File 'lib/photo_utils/formats.rb', line 112

def to_s(short=true)
  if short
    @name
  else
    "#{@name} (#{@frame})"
  end
end