Comment 27 for bug 408016

This also looks like part of the broken calculation:

trace:font:GetTextMetricsW text metrics:
    Weight = 400 FirstChar = 32 AveCharWidth = 65592
    Italic = 0 LastChar = 255 MaxCharWidth = 144302
    UnderLined = 255 DefaultChar = 129 Overhang = 0
    StruckOut = 255 BreakChar = 32 CharSet = 0
    PitchAndFamily = 21
    --------------------
    InternalLeading = 2
    Ascent = 11
    Descent = 2
    Height = 13

Normally AveCharWidth will be a small number, in various places it is a large number but whenever it is large the number is always 65592 and that does not make a plausible font width.

2^16 + 64 - 8 = 65592

Looks a lot like a 16 bit integer calculation gone wrong ?