Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
tree: dbbd5efd87
Fetching contributors…

Cannot retrieve contributors at this time

136 lines (107 sloc) 4.101 kb
require File.dirname(__FILE__) + '/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.
class Gruff::Line < Gruff::Base
# Draw a dashed line at the given value
attr_accessor :baseline_value
# Color of the baseline
attr_accessor :baseline_color
# Dimensions of lines and dots; calculated based on dataset size if left unspecified
attr_accessor :line_width
attr_accessor :dot_radius
# Hide parts of the graph to fit more datapoints, or for a different appearance.
attr_accessor :hide_dots, :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.
def initialize(*args)
raise ArgumentError, "Wrong number of arguments" if args.length > 2
if args.empty? or ((not Numeric === args.first) && (not String === args.first)) then
super()
else
super args.shift
end
@hide_dots = @hide_lines = false
@baseline_color = 'red'
@baseline_value = nil
end
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
if (defined?(@norm_baseline)) then
level = @graph_top + (@graph_height - @norm_baseline * @graph_height)
@d = @d.push
@d.stroke_color @baseline_color
@d.fill_opacity 0.0
@d.stroke_dasharray(10, 20)
@d.stroke_width 5
@d.line(@graph_left, level, @graph_left + @graph_width, level)
@d = @d.pop
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|
new_x = @graph_left + (@x_increment * index)
next if data_point.nil?
draw_label(new_x, index)
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 and !prev_x.nil? and !prev_y.nil? then
@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 = new_x
prev_y = new_y
end
end
@d.draw(@base_image)
end
def normalize
@maximum_value = [@maximum_value.to_f, @baseline_value.to_f].max
super
@norm_baseline = (@baseline_value.to_f / @maximum_value.to_f) if @baseline_value
end
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|
if !data_point.nil?
if one_point
# more than one point, bail
return false
else
# there is at least one data point
return true
end
end
end
return one_point
end
end
Jump to Line
Something went wrong with that request. Please try again.