UNRESOLVED BUGS

+ two_axes doesn't work correctly with negative numbers and zero_axis
+ y_max_value doesn't get adapted for bars and area if all negative values
+ init_graph does too much work for pies. Needs to be split up.
+ area chart doesn't do overwrite? Workaround: sum up your data sets, 
  and order them backwards (highest one first). Output graph will look 
  like it's incremental.
+ only bar charts do overwrite. Necessary to implement generally?

NOT REALLY BUGS

- The whole naming of x_label.*, x_tick.*, x_axis.* is very confused
  and confusing. Hard to fix without breaking backward compatibility.
- overwrite == 2 only makes sense if all the data is either positive,
  or negative
- A positive y_min_value doesn't work with bars or area, bars and area 
  always are set off against 0. Wether this is a bug, or wanted behaviour
  might be a point for discussion.
- y_min_value doesn't automatically get adapted for bars and area if 0
  is not included in the range, but only if user sets it. If left to
  figure it out itself, PNGgraph does it right.

FIXED IN 1.10

! When first value of a dataset is undef for a lines graph, things go 
  wrong.
  (report by Arto Nurmela <arto.nurmela@nmp.nokia.com>)

FIXED IN 1.04

! logo positioning and legends don't work very well together.

FIXED IN 1.03

! When data values are large, and x_min_value is larger than 0, the
  horizontal axis doesn't get drawm correctly. (check zero_axis option)
  (see sample41)
  (problem found after report from jackb@pgw.picker.com)

FIXED IN 1.02

! PNGgraph::Colour::read_rgb() falls over on comment lines.
	(reported: adamm@genomecorp.com)
! PNGgraph::Colour::read_rgb() contains inline my-declaration of $line, 
  breaks perl5.003 
	(reported: Pat Becker <pmb@iss.net>)
! if a colour name doesn't exist, program falls over with a cryptic message
  about some undefined array index.
	(reported: adamm@genomecorp.com)
! x_label_skip doesn't skip ticks. (also added x_all_ticks option)
	(reported: adamm@genomecorp.com)

FIXED IN 1.01

! for loops break in 5.003 because of 'my' scoping (grrrr) 
	(reported: Brian Eitrem <beitrem@digitalriver.com>)
! ticks get drawn in front of the data set 
	(reported: Honza Pazdziora <adelton@informatics.muni.cz>)
! length estimate of y labels needs to be done better
	(reported: Honza Pazdziora <adelton@informatics.muni.cz>)

FIXED IN 1.00

! PNGgraph::colour::sorted_colour_list() syntax error
! PNGgraph::colour pod documentation fixed
! placement of title is centered on png, not on graph.
! linespoints graph type initialises two GD::Image objects
! 'make test' fails on all tests on win32. binmode() needed.

FIXED IN 0.99

! Cannot use any 'null' values in graphs
	(reported: Lee Khandelwal <lee_khandelwal@il.us.swissbank.com>)

FIXED IN 0.95

! filled markers don't fill correctly when overlapping

FIXED IN 0.94

! area doesn't work with negative numbers
! Right axis doesn't get drawn when box_axis == 0 and two_axes == 1
! Color on front of 3D pies wrong with some data sets
	(reported: by various people)

FIXED IN 0.91

! Segmentation fault for 3d pies where last slice is small
	(reported: Dave Stafford <Dave.Stafford@mpn.cp.philips.com>)