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.
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 69 def initialize(*args) raise ArgumentError, 'Wrong number of arguments' if args.length > 2 if args.empty? || ((not Numeric === args.first) && (not String === args.first)) super() else super args.shift end @reference_lines = Hash.new @reference_line_default_color = 'red' @reference_line_default_width = 5 @hide_dots = @hide_lines = false @maximum_x_value = nil @minimum_x_value = nil end
# File lib/gruff/line.rb, line 47 def baseline_color if (@reference_lines.key?(:baseline)) @reference_lines[:baseline][:color] else nil end end
# File lib/gruff/line.rb, line 55 def baseline_color=(new_value) @reference_lines[:baseline] ||= Hash.new @reference_lines[:baseline][:color] = new_value end
Get the value if somebody has defined it.
# File lib/gruff/line.rb, line 33 def baseline_value if (@reference_lines.key?(:baseline)) @reference_lines[:baseline][:value] else nil end end
Set a value for a baseline reference line..
# File lib/gruff/line.rb, line 42 def baseline_value=(new_value) @reference_lines[:baseline] ||= Hash.new @reference_lines[:baseline][:value] = new_value end
# File lib/gruff/line.rb, line 288 def contains_one_point_only?(data_row) # Spin through data to determine if there is just one_value present. one_point = false data_row[DATA_VALUES_INDEX].each do |data_point| unless data_point.nil? if one_point # more than one point, bail return false end # there is at least one data point one_point = true end end one_point end
This method allows one to plot a dataset with both X and Y data.
Parameters are as follows:
name: string, the title of the dataset x_data_points: an array containing the x data points for the graph y_data_points: an array containing the y data points for the graph color: hex number indicating the line color as an RGB triplet or name: string, the title of the dataset xy_data_points: an array containing both x and y data points for the graph color: hex number indicating the line color as an RGB triplet Notes: -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().
Example:
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.
# File lib/gruff/line.rb, line 120 def dataxy(name, x_data_points=[], y_data_points=[], color=nil) raise ArgumentError, 'x_data_points is nil!' if x_data_points.length == 0 if x_data_points.all? { |p| p.is_a?(Array) && p.size == 2 } x_data_points, y_data_points = x_data_points.map { |p| p[0] }, x_data_points.map { |p| p[1] } 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 y data. self.data(name, y_data_points, color) x_data_points = Array(x_data_points) # make sure it's an array # append the x data to the last entry that was just added in the @data member @data.last[DATA_VALUES_X_INDEX] = x_data_points # Update the global min/max values for the x data x_data_points.each do |x_data_point| next if x_data_point.nil? # Setup max/min so spread starts at the low end of the data points if @maximum_x_value.nil? && @minimum_x_value.nil? @maximum_x_value = @minimum_x_value = x_data_point end @maximum_x_value = (x_data_point > @maximum_x_value) ? x_data_point : @maximum_x_value @minimum_x_value = (x_data_point < @minimum_x_value) ? x_data_point : @minimum_x_value end end
# File lib/gruff/line.rb, line 173 def draw super return unless @has_data # 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 @norm_data.each do |data_row| prev_x = prev_y = nil @one_point = contains_one_point_only?(data_row) data_row[DATA_VALUES_INDEX].each_with_index do |data_point, index| unless data_point prev_x = prev_y = nil next end x_data = data_row[DATA_VALUES_X_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[index], @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 new_y = @graph_top + (@graph_height - data_point * @graph_height) # Reset each time to avoid thin-line errors @d = @d.stroke data_row[DATA_COLOR_INDEX] @d = @d.fill data_row[DATA_COLOR_INDEX] @d = @d.stroke_opacity 1.0 @d = @d.stroke_width line_width || clip_value_if_greater_than(@columns / (@norm_data.first[DATA_VALUES_INDEX].size * 4), 5.0) circle_radius = dot_radius || clip_value_if_greater_than(@columns / (@norm_data.first[DATA_VALUES_INDEX].size * 2.5), 5.0) if !@hide_lines && !prev_x.nil? && !prev_y.nil? @d = @d.line(prev_x, prev_y, new_x, new_y) elsif @one_point # Show a circle if there's just one_point @d = @d.circle(new_x, new_y, new_x - circle_radius, new_y) end @d = @d.circle(new_x, new_y, new_x - circle_radius, new_y) unless @hide_dots prev_x, prev_y = new_x, new_y end end @d.draw(@base_image) end
# File lib/gruff/line.rb, line 163 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
# File lib/gruff/line.rb, line 153 def draw_reference_line(reference_line, left, right, top, bottom) @d = @d.push @d.stroke_color(reference_line[:color] || @reference_line_default_color) @d.fill_opacity 0.0 @d.stroke_dasharray(10, 20) @d.stroke_width(reference_line[:width] || @reference_line_default_width) @d.line(left, top, right, bottom) @d = @d.pop end
# File lib/gruff/line.rb, line 168 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
# File lib/gruff/line.rb, line 284 def get_x_coord(x_data_point, width, offset) x_data_point * width + offset end
# File lib/gruff/line.rb, line 254 def normalize(force=false) super(force) @reference_lines.each_value do |curr_reference_line| # We only care about horizontal markers ... for normalization. # Vertical markers won't have a :value, they will have an :index curr_reference_line[:norm_value] = ((curr_reference_line[:value].to_f - @minimum_value) / @spread.to_f) if (curr_reference_line.key?(:value)) end #normalize the x data if it is specified @data.each_with_index do |data_row, index| norm_x_data_points = [] if data_row[DATA_VALUES_X_INDEX] != nil data_row[DATA_VALUES_X_INDEX].each do |x_data_point| norm_x_data_points << ((x_data_point.to_f - @minimum_x_value.to_f) / (@maximum_x_value.to_f - @minimum_x_value.to_f)) end @norm_data[index] << norm_x_data_points end end end
# File lib/gruff/line.rb, line 235 def setup_data # Deal with horizontal reference line values that exceed the existing minimum & maximum values. possible_maximums = [@maximum_value.to_f] possible_minimums = [@minimum_value.to_f] @reference_lines.each_value do |curr_reference_line| if (curr_reference_line.key?(:value)) possible_maximums << curr_reference_line[:value].to_f possible_minimums << curr_reference_line[:value].to_f end end @maximum_value = possible_maximums.max @minimum_value = possible_minimums.min super end
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