Class: Bio::Graphics::Panel::Ruler

Inherits:
Object
  • Object
show all
Defined in:
lib/bio/graphics/ruler.rb

Overview

The Bio::Graphics::Ruler class describes the ruler to be drawn on the graph. This is created automatically when creating the picture by using Bio::Graphics::Panel.to_svg. See BioExt::Graphics documentation for explanation of interplay between different classes. – TODO: the ruler might be implemented as a special case of a track, so it would inherit from it (class Ruler < Bio::Graphics::Panel::Track). But I haven’t really thought this through yet. ++

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(panel, colour = [0,0,0]) ⇒ Ruler

Creates a new Bio::Graphics::Panel::Ruler object.

Arguments:

  • panel (required)

    Bio::Graphics::Panel object that this ruler

    belongs to

  • colour

    colour of the ruler. Default = ‘black’

Returns

Bio::Graphics::Ruler object



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# File 'lib/bio/graphics/ruler.rb', line 28

def initialize(panel, colour = [0,0,0])
  @panel = panel
  @name = 'ruler'
  @colour = colour
end

Instance Attribute Details

#colour ⇒ Object

Returns the value of attribute colour.



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# File 'lib/bio/graphics/ruler.rb', line 33

def colour
  @colour
end

#height ⇒ Object

Returns the value of attribute height.



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# File 'lib/bio/graphics/ruler.rb', line 33

def height
  @height
end

#major_tick_distance ⇒ Object

Returns the value of attribute major_tick_distance.



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# File 'lib/bio/graphics/ruler.rb', line 33

def major_tick_distance
  @major_tick_distance
end

#minor_tick_distance ⇒ Object

Returns the value of attribute minor_tick_distance.



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# File 'lib/bio/graphics/ruler.rb', line 33

def minor_tick_distance
  @minor_tick_distance
end

#name ⇒ Object

Returns the value of attribute name.



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# File 'lib/bio/graphics/ruler.rb', line 33

def name
  @name
end

#panel ⇒ Object

Returns the value of attribute panel.



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# File 'lib/bio/graphics/ruler.rb', line 33

def panel
  @panel
end

Instance Method Details

#calculate_tick_distance ⇒ Object 



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# File 'lib/bio/graphics/ruler.rb', line 35

def calculate_tick_distance
  min_tick_distance_requirement_met = false
  self.minor_tick_distance = 1 # in basepairs.
  while ! min_tick_distance_requirement_met
    if self.minor_tick_distance/panel.rescale_factor >= RULER_MIN_DISTANCE_TICKS_PIXEL
      min_tick_distance_requirement_met = true
    else
      self.minor_tick_distance = self.minor_tick_distance*5
    end
  end

  self.major_tick_distance = self.minor_tick_distance * 10
end

#draw(panel_drawing, vertical_offset) ⇒ Object 



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# File 'lib/bio/graphics/ruler.rb', line 49

def draw(panel_drawing, vertical_offset)
  ruler_drawing = Cairo::Context.new(panel_drawing)

  self.calculate_tick_distance

  # Draw line
  ruler_drawing.move_to(0,10)
  ruler_drawing.line_to(panel.width, 10)
  ruler_drawing.stroke

  # Draw ticks
  #  * Find position of first tick.
  #    Most of the time, we don't want the first tick on the very first
  #    basepair of the view. Suppose that would be position 333 in the
  #    sequence. Then the numbers under the major tickmarks would be:
  #    343, 353, 363, 373 and so on. Instead, we want 350, 360, 370, 380.
  #    So we want to find the position of the first tick.
  first_tick_position = panel.display_start
  while first_tick_position.modulo(minor_tick_distance) != 0
    first_tick_position += 1
  end
  
  #  * And start drawing the rest.
  first_tick_position.step(panel.display_stop, minor_tick_distance) do |tick|
    tick_pixel_position = (tick - panel.display_start) / panel.rescale_factor
    ruler_drawing.move_to(tick_pixel_position.floor, 5)
    if tick.modulo(major_tick_distance) == 0
      ruler_drawing.rel_line_to(0, 15)
      
      # Draw tick number
      ruler_drawing.select_font_face(*(FONT))
      ruler_drawing.set_font_size(RULER_TEXT_HEIGHT)
      ruler_drawing.move_to(tick_pixel_position.floor, 20 + RULER_TEXT_HEIGHT)
      ruler_drawing.show_text(tick.to_i.to_s)
    else
      ruler_drawing.rel_line_to(0, 5)
      
    end
    ruler_drawing.stroke
  end
  

  @height = 25 + RULER_TEXT_HEIGHT
end