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
Using a boxed slice means that we hold exactly the memory required
for the file data, rather than the next-power-of-two, which can
be wasteful when a large number of images are being sent to
the terminal.
This is a API breaking change for termwiz, so bump its version.
refs: #534
This corrects an issue where the mode byte of the DCS sequence was
discarded from the DcsHook, making it impossible to know what sequence
is being activated.
So far this hasn't come up as these sequences are relatively rare,
but in looking at sixel parsing I noticed the error.
This commit changes the behavior on Windows:
* If $TERM is set and the `terminfo` crate is able to
successfully initialize and locate a terminfo database (this also
requires that $TERMINFO be set in the environment), then we'll
use the `TerminfoRenderer` instead of the `WindowsConsoleRenderer`
* If $TERM is set to `xterm-256color` and no terminfo database was
found, use our modern compiled-in copy (look in the `termwiz/data/`
directory for the source and compiled version of this) and use
the `TerminfoRenderer`.
* Otherwise use the `WindowsConsoleRenderer`.
In practice, this allows termwiz apps to opt in to features such as
true color support on Windows 10 build 1903 an later by setting their
`TERM=xterm-256color`. This happens to be the default behavior when
`ssh`ing in to a windows host via `wezterm`.
You can see the truecolor mode get applied by running this example:
```
cargo run --example widgets_basic --features widgets
```
with TERM set as above the background region that is painted by the app
will be a blueish/purplish color, but with it unset or set to something
invalid, it will fall back to black.
I'd like to eventually make termwiz assume the equivalent configuration
to `TERM=xterm-256color` by default on Windows 10 build 1903 and later,
but it's worth getting some feedback on how this works for clients such
as `streampager`.
cc: @quark-zju and @markbt
