Created attachment 66191 [details]
Example of well and badly formatted axes label for dates
When creating a graph in LibreOffice sensible formatting of major/minor data labels is only supported for Bar graphs. That is, a simple bargraph can be created where the data labels are eg. the 1st of each month. For other graphs, such as line graphs or other XY graphs it is not possible to get labels on e.g. monthly or yearly basis (when leap years are included in the data set). Only workaround I have seen is to manually enter user labels on the graph.
It would be nice to have the option to configure any axis in any graph to be of special type such as date and be able to format the appearance of the axes accordingly.
In the attached example notice that double clicking the X-axes and looking at the Scale tab of the Format pop-up the chart has an option to use a Date type and select major/minor interals accordingly whereas the xy line graphs can not do that.
Download sheet attached
Insert - Chart
Chart Type - Column
Right click on X Axis Label (one of the dates)
Click "Format Axis..."
On Scale Tab, you'll see "Type" and you can select different types with options
Do the same with a line chart, you'll see that the options are not there.
Enhancement request, medium
Medium- our charts should behave the same way. Not any higher than medium because I don't think a lot of people even use this feature (first time for me :) ).
ProposedEasyHack as the code should be there and can be modeled by looking at how column chart is done.
Not an easy hack.
Chart2 code is one of the places that is horribly complicated and a endless source for confusion and regressions. Especially the date axis handling is quite non-intuitive.
I'd prefer if we won't mark chart2 bugs as ProposedEasyHacks because we have nobody who is confident enough to throw some code pointers into a bug report.
Summary amended for clarity and so it shows up more readily in searches.
Created attachment 134572 [details]
example of workaround for month axis in XY chart
I attached an example of a workaround with these settings:
Major interval: 61 (days)
Minor interval count: 2
Numbers format code: YYYY-MM (no days)
Interval marks, Minor: yes
This results in an interval mark for each month (every 30.5 days) with a label every second month.
The workaround is easier than adding manual tick labels, but at the cost of tick labels not appearing at the correct position. The skew is almost one day per year, and occasionally larger, for instance March 1 will be several days off.
In the long run a more general take is probably needed for intervals such as years and months and perhaps also supporting other calendars than western European.
Unfortunately I am not able to volunteer within any time soon.
Discussion about date scales in ODF is in https://issues.oasis-open.org/browse/OFFICE-2119 and currently on the TC mailing list.