Chris Bass authored Mar 22, 2017 and Sebastian Dröge committed Apr 09, 2017

The specified behaviour in TTML when lineHeight is "normal" is different
from the behaviour when a percentage is given. In the former case, the
line height is a percentage (the TTML spec recommends 125%) of the largest
font size that is applied to the spans within the block; in the latter
case, the line height is the given percentage of the font size that is
applied to the block itself.

The code doesn't correctly implement this behaviour; this patch fixes
that.

https://bugzilla.gnome.org/show_bug.cgi?id=780402