Created attachment 120429 [details]
Simple example .odt incl. underlined text of different sizes on the same line.
Underlining a range of text on the same line that uses different font sizes
causes the underline to be at different vertical positions and of different
thickness. This might be related to Bug 68573.
Steps to reproduce:
Load the attached .odt file.
Alternatively write a few words on one line, use different font sizes for
different parts of the text, then underline the whole line.
The 'underline' will visually differ depending on the used font size.
Reproduceable in LibreOffice 18.104.22.168
The 'underline' should be contiguous (same vertical position and thickness)
across the whole range (as long as that range of text is on the same line).
Microsoft Office 2016 does it that way, Office 2013 probably as well (couldn't
verify myself, though).
Not just related to bug 68573, rather it is the same issue. We don't make use of the font metrics.
If you need consistent underline-- select the text and use the Character dialog to apply a bottom border. Unfortunately the best you can do is touch the descenders of the fonts--would be nice if we could actually set spacing to contents negative to truly position underline.
*** This bug has been marked as a duplicate of bug 68573 ***