Class: Prawn::SVG::Calculators::DocumentSizing

Inherits:
Object
  • Object
show all
Defined in:
lib/prawn/svg/calculators/document_sizing.rb

Constant Summary collapse

DEFAULT_ASPECT_RATIO = 
'xMidYMid meet'.freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(bounds, attributes = nil) ⇒ DocumentSizing

Returns a new instance of DocumentSizing.



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# File 'lib/prawn/svg/calculators/document_sizing.rb', line 12

def initialize(bounds, attributes = nil)
  @bounds = bounds
  set_from_attributes(attributes) if attributes
end

Instance Attribute Details

#bounds ⇒ Object (readonly)

Returns the value of attribute bounds.



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# File 'lib/prawn/svg/calculators/document_sizing.rb', line 8

def bounds
  @bounds
end

#document_height=(value) ⇒ Object (writeonly)

Sets the attribute document_height

Parameters:

  • value —

    the value to set the attribute document_height to.



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# File 'lib/prawn/svg/calculators/document_sizing.rb', line 5

def document_height=(value)
  @document_height = value
end

#document_width=(value) ⇒ Object (writeonly)

Sets the attribute document_width

Parameters:

  • value —

    the value to set the attribute document_width to.



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# File 'lib/prawn/svg/calculators/document_sizing.rb', line 5

def document_width=(value)
  @document_width = value
end

#output_height ⇒ Object (readonly)

Returns the value of attribute output_height.



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# File 'lib/prawn/svg/calculators/document_sizing.rb', line 10

def output_height
  @output_height
end

#output_width ⇒ Object (readonly)

Returns the value of attribute output_width.



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# File 'lib/prawn/svg/calculators/document_sizing.rb', line 10

def output_width
  @output_width
end

#preserve_aspect_ratio=(value) ⇒ Object (writeonly)

Sets the attribute preserve_aspect_ratio

Parameters:

  • value —

    the value to set the attribute preserve_aspect_ratio to.



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# File 'lib/prawn/svg/calculators/document_sizing.rb', line 6

def preserve_aspect_ratio=(value)
  @preserve_aspect_ratio = value
end

#view_box=(value) ⇒ Object (writeonly)

Sets the attribute view_box

Parameters:

  • value —

    the value to set the attribute view_box to.



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# File 'lib/prawn/svg/calculators/document_sizing.rb', line 6

def view_box=(value)
  @view_box = value
end

#viewport_diagonal ⇒ Object (readonly)

Returns the value of attribute viewport_diagonal.



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# File 'lib/prawn/svg/calculators/document_sizing.rb', line 10

def viewport_diagonal
  @viewport_diagonal
end

#viewport_height ⇒ Object (readonly)

Returns the value of attribute viewport_height.



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# File 'lib/prawn/svg/calculators/document_sizing.rb', line 10

def viewport_height
  @viewport_height
end

#viewport_width ⇒ Object (readonly)

Returns the value of attribute viewport_width.



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# File 'lib/prawn/svg/calculators/document_sizing.rb', line 10

def viewport_width
  @viewport_width
end

#x_offset ⇒ Object (readonly)

Returns the value of attribute x_offset.



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# File 'lib/prawn/svg/calculators/document_sizing.rb', line 9

def x_offset
  @x_offset
end

#x_scale ⇒ Object (readonly)

Returns the value of attribute x_scale.



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# File 'lib/prawn/svg/calculators/document_sizing.rb', line 9

def x_scale
  @x_scale
end

#y_offset ⇒ Object (readonly)

Returns the value of attribute y_offset.



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# File 'lib/prawn/svg/calculators/document_sizing.rb', line 9

def y_offset
  @y_offset
end

#y_scale ⇒ Object (readonly)

Returns the value of attribute y_scale.



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# File 'lib/prawn/svg/calculators/document_sizing.rb', line 9

def y_scale
  @y_scale
end

Instance Method Details

#calculate ⇒ Object 



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# File 'lib/prawn/svg/calculators/document_sizing.rb', line 24

def calculate
  @x_offset = @y_offset = 0
  @x_scale = @y_scale = 1

  container_width = @requested_width || @bounds[0]
  container_height = @requested_height || @bounds[1]

  @output_width = Pixels::Measurement.to_pixels(@document_width || @requested_width, container_width)
  @output_height = Pixels::Measurement.to_pixels(@document_height || @requested_height, container_height)

  if @view_box
    values = @view_box.strip.split(Prawn::SVG::Elements::COMMA_WSP_REGEXP)
    @x_offset, @y_offset, @viewport_width, @viewport_height = values.map(&:to_f)

    if @viewport_width.positive? && @viewport_height.positive?
      # If neither the width nor height was specified, use the entire width and the viewbox ratio
      # to determine the height.
      @output_width = container_width if @output_width.nil? && @output_height.nil?

      # If one of the output dimensions is missing, calculate it from the other one
      # using the ratio of the viewport width to height.
      @output_width ||= @output_height * @viewport_width / @viewport_height
      @output_height ||= @output_width * @viewport_height / @viewport_width

      aspect = AspectRatio.new(@preserve_aspect_ratio, [@output_width, @output_height],
        [@viewport_width, @viewport_height])
      @x_scale = aspect.width / @viewport_width
      @y_scale = aspect.height / @viewport_height
      @x_offset -= aspect.x / @x_scale
      @y_offset -= aspect.y / @y_scale
    end
  else
    @output_width ||= container_width
    @output_height ||= container_height

    @viewport_width = @output_width
    @viewport_height = @output_height
  end

  return if invalid?

  # SVG 1.1 section 7.10
  @viewport_diagonal = Math.sqrt((@viewport_width**2) + (@viewport_height**2)) / Math.sqrt(2)

  if @requested_width
    scale = @requested_width / @output_width
    @output_width = @requested_width
    @output_height *= scale
    @x_scale *= scale
    @y_scale *= scale

  elsif @requested_height
    scale = @requested_height / @output_height
    @output_height = @requested_height
    @output_width *= scale
    @x_scale *= scale
    @y_scale *= scale
  end

  self
end

#invalid? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/prawn/svg/calculators/document_sizing.rb', line 86

def invalid?
  @viewport_width <= 0 ||
    @viewport_height <= 0 ||
    @output_width <= 0 ||
    @output_height <= 0 ||
    (@requested_width && @requested_width <= 0) ||
    (@requested_height && @requested_height <= 0)
end

#requested_height=(value) ⇒ Object 



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# File 'lib/prawn/svg/calculators/document_sizing.rb', line 99

def requested_height=(value)
  @requested_height = value&.to_f
end

#requested_width=(value) ⇒ Object 



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# File 'lib/prawn/svg/calculators/document_sizing.rb', line 95

def requested_width=(value)
  @requested_width = value&.to_f
end

#set_from_attributes(attributes) ⇒ Object 



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# File 'lib/prawn/svg/calculators/document_sizing.rb', line 17

def set_from_attributes(attributes)
  @document_width = attributes['width']
  @document_height = attributes['height']
  @view_box = attributes['viewBox']
  @preserve_aspect_ratio = attributes['preserveAspectRatio'] || DEFAULT_ASPECT_RATIO
end