This moves away from using special block glyphs for the lines and
just draws lines directly.
In addition, since these lines are no longer constrained to available
glyphs or glyph boundaries, we can now render lines that cross when
there are a mix of horizontal and vertical splits, which looks a
bit nicer.
refs: #1256
Assuming that the window config reloaded hook doesn't actually change
anything, this will avoid a cycle where we keep triggering the hook
over and over.
Not all codepoints are valid when combined with a presentation
selector.
This commit ensures that we respect the valid sequences defined
by the current version of unicode (version 14).
refs: #1231
refs: #997
As promised in the previous commit, this one implements an escape
sequence to control the unicode version.
Unknown to me in the previous commit, iTerm2 already defines such
an escape sequence, so we simply implement it here with the same
semantics.
refs: #1231
refs: #997
This is a fairly far-reaching commit. The idea is:
* Introduce a unicode_version config that specifies the default level
of unicode conformance for each newly created Terminal (each Pane)
* The unicode_version is passed down to the `grapheme_column_width`
function which interprets the width based on the version
* `Cell` records the width so that later calculations don't need to
know the unicode version
In a subsequent diff, I will introduce an escape sequence that allows
setting/pushing/popping the unicode version so that it can be overridden
via eg: a shell alias prior to launching an application that uses a
different version of unicode from the default.
This approach allows output from multiple applications with differing
understanding of unicode to coexist on the same screen a little more
sanely.
Note that the default `unicode_version` is set to 9, which means that
emoji presentation selectors are now by-default ignored. This was
selected to better match the level of support in widely deployed
applications.
I expect to raise that default version in the future.
Also worth noting: there are a number of callers of
`unicode_column_width` in things like overlays and lua helper functions
that pass `None` for the unicode version: these will assume the latest
known-to-wezterm/termwiz version of unicode to be desired. If those
overlays do things with emoji presentation selectors, then there may be
some alignment artifacts. That can be tackled in a follow up commit.
refs: #1231
refs: #997
We rely on using freetype in order to support more fonts in more
situations, and we have a deeper existing integration with harfbuzz.
I'm unlikely to come back to allsorts to complete our integration,
and in the meantime, it just adds overhead to build/test and those
builds are taking longer and longer.
I loved the idea of using pure rust for all the font stuff, but
its time is not now.
closes: #587closes: #66
