Calculation of default line spacing

[Ravelli]

Ahoy everybody,
does anyone happen to know how PSP calculates the default line spacing? Is it using winAscent, winDescent or something else? And is there a way to overwrite it, or even a fixed state?
Background of this is, I have two font files installed, old and new version of the same font face, Junicode and JuniusX. The new one seems to have a more modern technology. Both should show same line spacing, but PSP makes the line spacing of the new font higher. The developer of the font wrote me, that this would be an error on application side. And it seems he is right: I compared both fonts in some other applications, and they all do it correct. With the exception of PSP.
I'm still in PSP 2019, not convinced upgrading to 2021 yet. But will test the test version.
Friendly greetings,
Ravelli

[migf1]

I have no idea what calculations PSP does under the hood, but you can try adjusting the line spacing manually, via the Leading setting:
https://gyazo.com/1f4a4880334390b203f6a74ca4e7cf6a
(you can use decimal values, and you can limit the effect to selected lines only).

[Ravelli]

Hello migf1,
and many thanks for your reply and the effort taking the screen capture.
Yes, this manual setting would be an alternative, but causing maybe a month of work to adjust all my current project files. It would also cause additional work each time I create a new work. I want PSP and the font working properly on default, without manual adjusting. So I try investigating the background of it.
Friendly greetings,
Ravelli

[Jean-Luc]

does anyone happen to know how PSP calculates the default line spacing? Is it using winAscent, winDescent or something else? And is there a way to overwrite it, or even a fixed state?

I think it is hardcoded and no way to change it.
Did you test with previous PSP versions?
I have PSP 8 (Jasc) and X7 (and followings). I have observed that In PSP 8, the way PSP manipulates fonts is different from the way Corel does it in the X versions. But 8 (Jasc) is an old program.
It would be interesting to submit the problem to Corel.