Created attachment 172084 [details]
Example file from Excel

Attached XLSX file demonstrates that MSO by default uses a “Best” rotation for horizontal category axes of charts (Bar, Line, Point, Area).
On the UI it is shown as “Horizontal” text rotation, with undefined rotation angle. This is misleading a bit, since the actual text rotation will be determined based on the actual text length of the axis labels:
- with short labels/wide chart it’s gonna be horizontal
- with medium length labels it’s gonna be -45 degrees (in Word terms)
- with long labels it’s gonna be 270 degrees (in Word terms)

LO can display the text in the first two cases (when the labels overlap property is turned off manually, needed right now because of bug #140623) but it would be nice to be able to better mimic the vertical rotation of long labels; possibly with an explicit UI option (to be filed later).

Steps to reproduce:
1.	Open attached file
2.	For the first chart, open the X axis properties

Actual results:
The X axis text is not rotated to 270 degrees, but to -45 even if the Overlap property is manually turned off. 
The Text Orientation dial indicates 0 degrees orientation, which is false: that would mean the labels are horizontal. 
Ideally, there would be an “Automatic” checkbox (or radio button paired with “Vertically stacked” option) that disables this dial and sets rotation based on actual text length + font size + available space. This could be a topic for another report.

Expected results:
The X axis text should be rotated to 270 degrees.