I have a number of Gruff Graphs of various types however for a Line graph I have the following problem:
(Gruff v0.3.6)

handle = Gruff::Line.new('800x500')
handle.y_axis_increment = 25

This generates the following message:

wrong number of arguments (1 for 0)

/Library/Ruby/Gems/1.8/gems/gruff-0.3.6/lib/gruff/base.rb:687:in `normalize'
/Library/Ruby/Gems/1.8/gems/gruff-0.3.6/lib/gruff/base.rb:687:in `draw_line_markers'
/Library/Ruby/Gems/1.8/gems/gruff-0.3.6/lib/gruff/base.rb:536:in `setup_drawing'
/Library/Ruby/Gems/1.8/gems/gruff-0.3.6/lib/gruff/base.rb:508:in `draw'
/Library/Ruby/Gems/1.8/gems/gruff-0.3.6/lib/gruff/line.rb:53:in `draw'
/Library/Ruby/Gems/1.8/gems/gruff-0.3.6/lib/gruff/base.rb:493:in `to_blob'
...

Date: 2009-08-27 15:15
Sender: David Walker

This is a duplicate of bug 9109
The fix is simple on line 112 of line.rb 

 def normalize()
becomes
 def normalize(force=false)