The attached patch fixes this by using the GDI measurement for the
vertical size of text.
Doing the same with DirectWrite would be too expensive, and would imply
using the "layout" parts of DirectWrite, to get the same results most of
the time.
Hmm... are we sure the GDI measurement will work always for the fonts
for which we must use DirectWrite? For example, the color fonts?
If GDI might fail for some fonts, perhaps leaving the metrics code in
w32_dwrite_text_extents, and then _overriding_ that by GDI values if
available, would be safer?