Class: HexaPDF::Layout::LineFragment::HeightCalculator

Inherits:
Object
  • Object
show all
Defined in:
lib/hexapdf/layout/line_fragment.rb

Overview

Helper class for calculating the needed vertical dimensions of a line.

Instance Method Summary collapse

Constructor Details

#initialize(items = []) ⇒ HeightCalculator

Creates a new calculator with the given initial items.



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# File 'lib/hexapdf/layout/line_fragment.rb', line 95

def initialize(items = [])
  reset
  items.each {|item| add(item)}
end

Instance Method Details

#add(item) ⇒ Object Also known as: <<

Adds a new item to be considered when calculating the various dimensions.



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# File 'lib/hexapdf/layout/line_fragment.rb', line 101

def add(item)
  case item.valign
  when :text
    @text_y_min = item.y_min if item.y_min < @text_y_min
    @text_y_max = item.y_max if item.y_max > @text_y_max
  when :baseline
    @max_base_height = item.height if @max_base_height < item.height
  when :top
    @max_top_height = item.height if @max_top_height < item.height
  when :text_top
    @max_text_top_height = item.height if @max_text_top_height < item.height
  when :bottom
    @max_bottom_height = item.height if @max_bottom_height < item.height
  when :text_bottom
    @max_text_bottom_height = item.height if @max_text_bottom_height < item.height
  else
    raise HexaPDF::Error, "Unknown inline box alignment #{item.valign}"
  end
  self
end

#reset ⇒ Object

Resets the calculation.



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# File 'lib/hexapdf/layout/line_fragment.rb', line 136

def reset
  @text_y_min = 0
  @text_y_max = 0
  @max_base_height = 0
  @max_top_height = 0
  @max_text_top_height = 0
  @max_bottom_height = 0
  @max_text_bottom_height = 0
end

#result ⇒ Object

Returns the result of the calculations, the array [y_min, y_max, text_y_min, text_y_max].

See LineFragment for their meaning.



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# File 'lib/hexapdf/layout/line_fragment.rb', line 126

def result
  y_min = [@text_y_max - @max_text_top_height, @text_y_min].min
  y_max = [@text_y_min + @max_text_bottom_height, @max_base_height, @text_y_max].max
  y_min = [y_max - @max_top_height, y_min].min
  y_max = [y_min + @max_bottom_height, y_max].max

  [y_min, y_max, @text_y_min, @text_y_max]
end

#simulate_height(item) ⇒ Object

Returns the height of the line as if item was part of it but doesn’t change the internal state.



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# File 'lib/hexapdf/layout/line_fragment.rb', line 148

def simulate_height(item)
  text_y_min = @text_y_min
  text_y_max = @text_y_max
  max_base_height = @max_base_height
  max_top_height = @max_top_height
  max_text_top_height = @max_text_top_height
  max_bottom_height = @max_bottom_height
  max_text_bottom_height = @max_text_bottom_height
  y_min, y_max, = add(item).result
  y_max - y_min
ensure
  @text_y_min = text_y_min
  @text_y_max = text_y_max
  @max_base_height = max_base_height
  @max_top_height = max_top_height
  @max_text_top_height = max_text_top_height
  @max_bottom_height = max_bottom_height
  @max_text_bottom_height = max_text_bottom_height
end