Class | Gruff::Line |
In: |
lib/gruff/line.rb
|
Parent: | Gruff::Base |
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.
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. |
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.
# 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
# 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[DATA_VALUES_INDEX].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[DATA_VALUES_INDEX].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[DATA_VALUES_INDEX].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