This adds functionality for choosing different normalization metrics for
each fallback font. It's not exposed as a config option, but could be in
the future, which would probably go a long way towards addressing
concerns like #7929.
The currently available reference metrics are, in priority order:
`ic_width, ex_height, cap_height, line_height, em_size`. The default
value is `ic_width`.
By priority order, I mean that if the chosen metric is not defined in
the fallback font, we move to the next metric in the list---we don't
normalize by an estimated metric from the fallback font (however, we're
happy to use an estimated metric from the primary font, that's how
`ic_width` normalization between CJK and Latin fonts work). This extends
the pattern that was used between `ic_width` and `ex_height` in the
existing hardcoded rule. `line_height` is always defined, so the buck
stops there.
What motivated me to implement this was the fact that, with the existing
hardcoded rule, the embedded symbols-only Nerd Font was always scaled up
by a factor of 1.2, which turned out to be an important reason why it's
been difficult to make icon scaling work to everyone's satisfaction.
Accordingly, the symbols-only font is the first to take advantage of the
new functionality. If this PR is merged, #7917 is no longer needed. (To
limit the scope of this PR, it only includes the minimal changes to let
icon scaling take advantage of this functionality. I may submit a
follow-up PR with some further icon scaling improvement enabled by
this.)
This ports over a basic headerbar, maximize, and fullscreen. The
headerbar only has the main menu button for now since we have no tabbing
or splits. The main menu has the full main menu that mainline GTK has
but most of it is disabled since we don't implement the actions yet.
I didn't use anything from your branch @tristan957 so I didn't add
coauthor but I want to note that @tristan957 worked on this as well and
I suspect there's overlap.
