Class Gruff::Line
In: lib/gruff/line.rb
Parent: Gruff::Base
Scene Pie StackedBar Area PhotoBar Spider SideBar Net StackedArea Bar Line Pie StackedMixin SideStackedBar AccumulatorBar Observable Group SideBar StandardError IncorrectNumberOfDatasetsException Magick Bar Layer BarConversion lib/gruff/stacked_area.rb lib/gruff/scene.rb lib/gruff/spider.rb lib/gruff/pie.rb lib/gruff/area.rb lib/gruff/net.rb lib/gruff/bar_conversion.rb lib/gruff/bar.rb lib/gruff/side_bar.rb lib/gruff/line.rb lib/gruff/stacked_bar.rb lib/gruff/side_stacked_bar.rb lib/gruff/photo_bar.rb lib/gruff/base.rb lib/gruff/accumulator_bar.rb Deprecated lib/gruff/mini/bar.rb lib/gruff/mini/side_bar.rb lib/gruff/mini/pie.rb Legend Mini StackedMixin Base Gruff dot/m_20_0.png

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.

Methods

draw   new   normalize  

Attributes

baseline_color  [RW]  Color of the baseline
baseline_value  [RW]  Draw a dashed line at the given value
hide_dots  [RW]  Hide parts of the graph to fit more datapoints, or for a different appearance.
hide_lines  [RW]  Hide parts of the graph to fit more datapoints, or for a different appearance.

Public Class methods

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.

[Source]

    # File lib/gruff/line.rb, line 35
35:   def initialize(*args)
36:     raise ArgumentError, "Wrong number of arguments" if args.length > 2
37:     if args.empty? or ((not Numeric === args.first) && (not String === args.first)) then
38:       super()
39:     else
40:       super args.shift
41:     end
42:     
43:     @hide_dots = @hide_lines = false
44:     @baseline_color = 'red'
45:     @baseline_value = nil
46:   end

Public Instance methods

[Source]

    # File lib/gruff/line.rb, line 48
48:   def draw
49:     super
50: 
51:     return unless @has_data
52:     
53:     # Check to see if more than one datapoint was given. NaN can result otherwise.  
54:     @x_increment = (@column_count > 1) ? (@graph_width / (@column_count - 1).to_f) : @graph_width
55:      
56:     if (defined?(@norm_baseline)) then
57:       level = @graph_top + (@graph_height - @norm_baseline * @graph_height)
58:       @d = @d.push
59:       @d.stroke_color @baseline_color
60:       @d.fill_opacity 0.0
61:       @d.stroke_dasharray(10, 20)
62:       @d.stroke_width 5
63:       @d.line(@graph_left, level, @graph_left + @graph_width, level)
64:       @d = @d.pop
65:     end
66: 
67:     @norm_data.each do |data_row|      
68:       prev_x = prev_y = nil
69: 
70:       data_row[1].each_with_index do |data_point, index|
71:         new_x = @graph_left + (@x_increment * index)
72:         next if data_point.nil?
73: 
74:         draw_label(new_x, index)
75: 
76:         new_y = @graph_top + (@graph_height - data_point * @graph_height)
77: 
78:         # Reset each time to avoid thin-line errors
79:         @d = @d.stroke data_row[DATA_COLOR_INDEX]
80:         @d = @d.fill data_row[DATA_COLOR_INDEX]
81:         @d = @d.stroke_opacity 1.0
82:         @d = @d.stroke_width clip_value_if_greater_than(@columns / (@norm_data.first[1].size * 4), 5.0)
83: 
84:         if !@hide_lines and !prev_x.nil? and !prev_y.nil? then          
85:           @d = @d.line(prev_x, prev_y, new_x, new_y)
86:         end
87:         circle_radius = clip_value_if_greater_than(@columns / (@norm_data.first[1].size * 2.5), 5.0)
88:         @d = @d.circle(new_x, new_y, new_x - circle_radius, new_y) unless @hide_dots
89: 
90:         prev_x = new_x
91:         prev_y = new_y
92:       end
93: 
94:     end
95: 
96:     @d.draw(@base_image)
97:   end

[Source]

     # File lib/gruff/line.rb, line 99
 99:   def normalize
100:     @maximum_value = [@maximum_value.to_f, @baseline_value.to_f].max
101:     super
102:     @norm_baseline = (@baseline_value.to_f / @maximum_value.to_f) if @baseline_value
103:   end

[Validate]