Old font functionality has been moved into BitmapFont
and an abstract Font interface has been introduced to
faciliate further development of TTF font integration.
Compared to version 10 this fixes a bunch of formatting issues, mostly
around structs/classes with attributes like [[gnu::packed]], and
incorrect insertion of spaces in parameter types ("T &"/"T &&").
I also removed a bunch of // clang-format off/on and FIXME comments that
are no longer relevant - on the other hand it tried to destroy a couple of
neatly formatted comments, so I had to add some as well.
We previously had a cached bold variant font in Gfx::Font that was very
haphazardly located by filename pattern. This patches replaces that
mechanism with a proper Gfx::FontDatabase lookup for the same font but
with bold weight (700).
The qualified name of a font is "<Family> <Size> <Weight>". You can
get the QN of a Font via the Font::qualified_name() API, and you can
get any system font by QN from the GUI::FontDatabase. :^)
The main inspiration behind this was to have a correct ex CSS unit.
The mean line is based off what it shows in the CSS Values and Units
Level 4 specification, section 6.1.1.
https://www.w3.org/TR/css-values-4/#font-relative-lengths
Right now we just guess that the x-height is glyph_height/2, which is
obviously not accurate. We currently don't store the x-height in fonts,
so that's something we'll need to fix.
