fix 918 - Axis label rounding issues

[mdkh1311]

Summary

Fix for #918

Solves

#918

[taoyouh]

I think your solution is too complicated.
The problem here is the "rounding" isn't really a rounding. It's a truncation. You just need to change the Truncate to Round, and the problem will be solved.

[mdkh1311]

It's not so clear cut even with rounding however since to how many decimal places do you round to and what style of rounding do you use: AwayFromZero or ToEven? The signature of Math.Round is:

public static decimal Round (decimal d, int decimals, MidpointRounding mode);

I have a requirement to round to 4 decimal places, but I doubt other people do

[taoyouh]

It's not so clear cut even with rounding however since to how many decimal places do you round to and what style of rounding do you use: AwayFromZero or ToEven? The signature of Math.Round is:

public static decimal Round (decimal d, int decimals, MidpointRounding mode);

I have a requirement to round to 4 decimal places, but I doubt other people do

In my PR #942 , if you set the "Unit" property, the algorithm will round the labels to make (labelValue / Unit) integral. You can round to any decimal places or even round to *.5 / *.0 if you like. I tested the case you mentioned in #918 and it works just as what you expected.

I think this is what the original algorithm intends to do, but 1) it only rounds the first label instead of every one, and 2) it used truncation instead of rounding.

I think the rounding style isn't important in this situation. The rounding is just for fixing the number very close to the target value, such as 0.999999->1 and I don't think AwayFromZero or ToEven matters.

[mdkh1311]

Ah ok that makes sense. Thanks very much for finding a solution