Class: Gruff::Line

Inherits:
Base
  • Object
show all
Defined in:
lib/gruff/line.rb

Overview

Here’s how to make a Line graph:

g = Gruff::Line.new
g.title = "A Line Graph"
g.data 'Fries', [20, 23, 19, 8]
g.data 'Hamburgers', [50, 19, 99, 29]
g.write("test/output/line.png")

There are also other options described below, such as #baseline_value, #baseline_color, #hide_dots, and #hide_lines.

Constant Summary

Constants inherited from Base

Base::DEFAULT_MARGIN, Base::DEFAULT_TARGET_WIDTH, Base::LABEL_MARGIN, Base::LEGEND_MARGIN, Base::THOUSAND_SEPARATOR

Instance Attribute Summary collapse

Attributes inherited from Base

#additional_line_values, #bold_title, #bottom_margin, #center_labels_over_point, #colors, #font, #font_color, #has_left_labels, #hide_legend, #hide_line_markers, #hide_line_numbers, #hide_title, #label_max_size, #label_stagger_height, #label_truncation_style, #labels, #left_margin, #legend_at_bottom, #legend_box_size, #legend_font_size, #legend_margin, #marker_color, #marker_count, #marker_font_size, #marker_shadow_color, #maximum_value, #minimum_value, #no_data_message, #right_margin, #sort, #sorted_drawing, #title, #title_font, #title_font_size, #title_margin, #top_margin, #use_data_label, #x_axis_increment, #x_axis_label, #y_axis_increment, #y_axis_label

Instance Method Summary collapse

Methods inherited from Base

#add_color, #data, #margins=, #replace_colors, #theme=, #theme_37signals, #theme_greyscale, #theme_keynote, #theme_odeo, #theme_pastel, #theme_rails_keynote, #to_blob, #write

Constructor Details

#initialize(*args) ⇒ Line

Call with target pixel width of graph (800, 400, 300), and/or false to omit lines (points only).

g = Gruff::Line.new(400) # 400px wide with lines
g = Gruff::Line.new(400, false) # 400px wide, no lines (for backwards compatibility)
g = Gruff::Line.new(false) # Defaults to 800px wide, no lines (for backwards compatibility)

The preferred way is to call #hide_dots or #hide_lines instead.

Raises:

  • (ArgumentError) 


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# File 'lib/gruff/line.rb', line 71

def initialize(*args)
  raise ArgumentError, 'Wrong number of arguments' if args.length > 2

  if args.empty? || (!args.first.is_a?(Numeric) && !args.first.is_a?(String))
    super()
  else
    super args.shift
  end

  @reference_lines = {}
  @reference_line_default_color = 'red'
  @reference_line_default_width = 5

  @hide_dots = @hide_lines = false
  @maximum_x_value = nil
  @minimum_x_value = nil

  @dot_style = 'circle'

  @show_vertical_markers = false

  @store = Gruff::Store.new(Gruff::Store::XYData)
end

Instance Attribute Details

#dot_radius ⇒ Object

Returns the value of attribute dot_radius.



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# File 'lib/gruff/line.rb', line 26

def dot_radius
  @dot_radius
end

#dot_style ⇒ Object

default is ‘circle’, other options include square.



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# File 'lib/gruff/line.rb', line 29

def dot_style
  @dot_style
end

#hide_dots ⇒ Object

Hide parts of the graph to fit more datapoints, or for a different appearance.



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# File 'lib/gruff/line.rb', line 32

def hide_dots
  @hide_dots
end

#hide_lines ⇒ Object

Hide parts of the graph to fit more datapoints, or for a different appearance.



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# File 'lib/gruff/line.rb', line 32

def hide_lines
  @hide_lines
end

#line_width ⇒ Object

Dimensions of lines and dots; calculated based on dataset size if left unspecified.



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# File 'lib/gruff/line.rb', line 25

def line_width
  @line_width
end

#maximum_x_value ⇒ Object

accessors for support of xy data.



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# File 'lib/gruff/line.rb', line 38

def maximum_x_value
  @maximum_x_value
end

#minimum_x_value ⇒ Object

accessors for support of xy data.



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# File 'lib/gruff/line.rb', line 35

def minimum_x_value
  @minimum_x_value
end

#reference_line_default_color ⇒ Object

Returns the value of attribute reference_line_default_color.



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# File 'lib/gruff/line.rb', line 18

def reference_line_default_color
  @reference_line_default_color
end

#reference_line_default_width ⇒ Object

Returns the value of attribute reference_line_default_width.



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# File 'lib/gruff/line.rb', line 19

def reference_line_default_width
  @reference_line_default_width
end

#reference_lines ⇒ Object

Allow for reference lines ( which are like baseline … just allowing for more & on both axes ).



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# File 'lib/gruff/line.rb', line 17

def reference_lines
  @reference_lines
end

#show_vertical_markers ⇒ Object

Allow for vertical marker lines.



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# File 'lib/gruff/line.rb', line 22

def show_vertical_markers
  @show_vertical_markers
end

Instance Method Details

#baseline_color ⇒ Object 



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# File 'lib/gruff/line.rb', line 53

def baseline_color
  if @reference_lines.key?(:baseline)
    @reference_lines[:baseline][:color]
  end
end

#baseline_color=(new_value) ⇒ Object 



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# File 'lib/gruff/line.rb', line 59

def baseline_color=(new_value)
  @reference_lines[:baseline] ||= {}
  @reference_lines[:baseline][:color] = new_value
end

#baseline_value ⇒ Object

Get the value if somebody has defined it.



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# File 'lib/gruff/line.rb', line 41

def baseline_value
  if @reference_lines.key?(:baseline)
    @reference_lines[:baseline][:value]
  end
end

#baseline_value=(new_value) ⇒ Object

Set a value for a baseline reference line..



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# File 'lib/gruff/line.rb', line 48

def baseline_value=(new_value)
  @reference_lines[:baseline] ||= {}
  @reference_lines[:baseline][:value] = new_value
end

#dataxy(name, x_data_points = [], y_data_points = [], color = nil) ⇒ Object #dataxy(name, xy_data_points = [], color = nil) ⇒ Object

Note:

  • if (x_data_points.length != y_data_points.length) an error is returned.

  • if the color argument is nil, the next color from the default theme will be used.

  • if you want to use a preset theme, you must set it before calling #dataxy.

This method allows one to plot a dataset with both X and Y data.

Examples:

g = Gruff::Line.new
g.title = "X/Y Dataset"
g.dataxy("Apples", [1,3,4,5,6,10], [1, 2, 3, 4, 4, 3])
g.dataxy("Bapples", [1,3,4,5,7,9], [1, 1, 2, 2, 3, 3])
g.dataxy("Capples", [[1,1],[2,3],[3,4],[4,5],[5,7],[6,9]])

# you can still use the old data method too if you want:
g.data("Capples", [1, 1, 2, 2, 3, 3])

# labels will be drawn at the x locations of the keys passed in.
In this example the lables are drawn at x positions 2, 4, and 6:
g.labels = {0 => '2003', 2 => '2004', 4 => '2005', 6 => '2006'}
# The 0 => '2003' label will be ignored since it is outside the chart range.

Overloads:

  • #dataxy(name, x_data_points = [], y_data_points = [], color = nil) ⇒ Object

    Parameters:

    • name (String) —

      the title of the dataset.

    • x_data_points (Array) (defaults to: []) —

      an array containing the x data points for the graph.

    • y_data_points (Array) (defaults to: []) —

      an array containing the y data points for the graph.

    • color (String) (defaults to: nil) —

      hex number indicating the line color as an RGB triplet.

  • #dataxy(name, xy_data_points = [], color = nil) ⇒ Object

    Parameters:

    • name (String) —

      the title of the dataset.

    • xy_data_points (Array) (defaults to: []) —

      an array containing both x and y data points for the graph.

    • color (String) (defaults to: nil) —

      hex number indicating the line color as an RGB triplet.

Raises:

  • (ArgumentError) 


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# File 'lib/gruff/line.rb', line 129

def dataxy(name, x_data_points = [], y_data_points = [], color = nil)
  # make sure it's an array
  x_data_points = Array(x_data_points)
  y_data_points = Array(y_data_points)

  raise ArgumentError, 'x_data_points is nil!' if x_data_points.empty?

  if x_data_points.all? { |p| p.is_a?(Array) && p.size == 2 }
    x_data_points, y_data_points = x_data_points.transpose
  end

  raise ArgumentError, 'x_data_points.length != y_data_points.length!' if x_data_points.length != y_data_points.length

  # call the existing data routine for the x/y data.
  store.add(name, y_data_points, color, x_data_points)
end

#draw ⇒ Object 



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# File 'lib/gruff/line.rb', line 164

def draw
  super

  return unless data_given?

  # Check to see if more than one datapoint was given. NaN can result otherwise.
  @x_increment = (column_count > 1) ? (@graph_width / (column_count - 1).to_f) : @graph_width

  @reference_lines.each_value do |curr_reference_line|
    draw_horizontal_reference_line(curr_reference_line) if curr_reference_line.key?(:norm_value)
    draw_vertical_reference_line(curr_reference_line) if curr_reference_line.key?(:index)
  end

  if @show_vertical_markers
    (0..column_count).each do |column|
      x = @graph_left + @graph_width - column.to_f * @x_increment

      Gruff::Renderer::Line.new(color: @marker_color).render(x, @graph_bottom, x, @graph_top)
      #If the user specified a marker shadow color, draw a shadow just below it
      if @marker_shadow_color
        Gruff::Renderer::Line.new(color: @marker_shadow_color).render(x + 1, @graph_bottom, x + 1, @graph_top)
      end
    end
  end

  store.norm_data.each do |data_row|
    prev_x = prev_y = nil

    one_point = contains_one_point_only?(data_row)

    data_row.coordinates.each_with_index do |(x_data, y_data), index|
      if x_data.nil?
        #use the old method: equally spaced points along the x-axis
        new_x = @graph_left + (@x_increment * index)
        draw_label(new_x, index)
      else
        new_x = get_x_coord(x_data, @graph_width, @graph_left)
        @labels.each do |label_pos, _|
          draw_label(@graph_left + ((label_pos - @minimum_x_value) * @graph_width) / (@maximum_x_value - @minimum_x_value), label_pos)
        end
      end
      unless y_data # we can't draw a line for a null data point, we can still label the axis though
        prev_x = prev_y = nil
        next
      end

      new_y = @graph_top + (@graph_height - y_data * @graph_height)

      # Reset each time to avoid thin-line errors
      stroke_width  = line_width || clip_value_if_greater_than(@columns / (store.norm_data.first.y_points.size * 4), 5.0)
      circle_radius = dot_radius || clip_value_if_greater_than(@columns / (store.norm_data.first.y_points.size * 2.5), 5.0)

      if !@hide_lines && prev_x && prev_y
        Gruff::Renderer::Line.new(color: data_row.color, width: stroke_width)
                             .render(prev_x, prev_y, new_x, new_y)
      end

      if one_point || !@hide_dots
        Gruff::Renderer::Dot.new(@dot_style, color: data_row.color, width: stroke_width).render(new_x, new_y, circle_radius)
      end

      prev_x = new_x
      prev_y = new_y
    end
  end

  Gruff::Renderer.finish
end

#draw_horizontal_reference_line(reference_line) ⇒ Object 



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# File 'lib/gruff/line.rb', line 154

def draw_horizontal_reference_line(reference_line)
  level = @graph_top + (@graph_height - reference_line[:norm_value] * @graph_height)
  draw_reference_line(reference_line, @graph_left, @graph_left + @graph_width, level, level)
end

#draw_reference_line(reference_line, left, right, top, bottom) ⇒ Object 



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# File 'lib/gruff/line.rb', line 146

def draw_reference_line(reference_line, left, right, top, bottom)
  config = {
    color: reference_line[:color] || @reference_line_default_color,
    width: reference_line[:width] || @reference_line_default_width
  }
  Gruff::Renderer::DashLine.new(config).render(left, top, right, bottom)
end

#draw_vertical_reference_line(reference_line) ⇒ Object 



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# File 'lib/gruff/line.rb', line 159

def draw_vertical_reference_line(reference_line)
  index = @graph_left + (@x_increment * reference_line[:index])
  draw_reference_line(reference_line, index, index, @graph_top, @graph_top + @graph_height)
end