Start position of grid not specified

Hi all,

while working on "logarithmic axis scale" [1] in the ODF TC we noticed, 
that positioning of grid is generally different between LO and Gnumeric.

Gnumeric has a position independent of the minimum of the axis. LO 
starts grid always at the minimum of the axis. Example: currently for a 
major-interval=2 and min=-2.5 LO gives grid position -2.5, -0.5, 1.5 and 
for min=-1.5 LO give grid position -1.5, 0.5, 2.5.

It would be nice to determine the grid position for to get -2, 0, 2 
independent of minimum value.

I can imagine of a new style attribute chart:grid-anchor where you can 
set a value (0 for linear scale e.g) or "start" (to get the current 
behavior). But as this would require additions in the code, I will not 
suggest it to the TC without your OK.

Currently the spec has no rule for it, so both LO and Gnumeric are 
"right". But for interoperability it is a bad situation and the spec 
should describe the grid position.

[1] https://issues.oasis-open.org/browse/OFFICE-3936

Kind regards
Regina