strans/README.md

# strans

strans is a small, single-user input method for Korean, Japanese, English,
emoji, and symbols. It provides one engine for IBus, XIM, and GTK 3.
Vietnamese Telex is also available as a compatibility mode.

## Input modes

| Key | Mode |
| --- | --- |
| `Ctrl+N` | Japanese Hiragana and Kanji conversion |
| `Ctrl+K` | Japanese Katakana |
| `Ctrl+S` | Korean Hangul (2-beolsik) |
| `Ctrl+T` | English |
| `Ctrl+V` | Vietnamese Telex |
| `Ctrl+E` | Emoji and symbol search |
| `Ctrl+H` | One-shot Hanja search |

A Korean keyboard's 한/영 key toggles Korean and English, and its 한자 key
is `Ctrl+H`; a Japanese keyboard's 半角/全角 toggles Japanese and English,
ひらがな/カタカナ switches between the two kana modes, 変換 turns Japanese on
and then converts like `Space`, and 無変換 turns it off. Only a plain `Ctrl` chord is a strans key: with `Shift`, `Alt`,
or `Super` held it commits what is pending and goes to the application, so
`Ctrl+Shift+V` still pastes.

A complete Japanese reading shows its Kanji candidates with none chosen.
`Space` chooses the first and then steps on, wrapping (`Shift+Space` steps
back); `Up`/`Down` and `PageUp`/`PageDown` move without wrapping. An
unmodified `1`-`9` commits that row of the current page. `Enter` and `Tab`
commit the chosen candidate, or the reading when none is chosen, as `0`
always does; so does typing on, or any key that ends the composition.
Japanese consumes the confirming key; Korean and Vietnamese pass it on to
the application. `Space` adds the reading in Katakana as the last
candidate, so a word the dictionary lacks converts to Katakana with one
`Space`. `Backspace` and `Esc` on a chosen candidate go back to the
reading. In a temporary Emoji or Hanja search, `Enter` commits the
highlighted result and `Tab`/`Shift-Tab` wrap through the results. Leaving
the field or clicking elsewhere commits what is pending. `Esc` cancels a
Japanese reading or a search; in Korean and Vietnamese it commits the
syllable and goes on to the application, so it still leaves insert mode.

Hiragana mode composes a complete reading before offering Kanji candidates.
Katakana mode does not perform Kanji conversion. Emoji and Hanja searches
return to the previous mode after use; switching language during a search
commits the shown query; `Esc` in a Hanja search gives the syllable back
to the composition. The Emoji search matches the typed keys, and what
they spell in the current language, against a prefix of every emoji's
CLDR name and keywords in English, Korean, and Japanese, and against ASCII
symbol aliases such as `->` and `<=`. `Ctrl+H` takes the syllable being composed as its
query; the Hanja dictionary lists one modern Hangul syllable at a time.

## Preedit and candidates

| Frontend | Preedit | Candidates |
| --- | --- | --- |
| GTK 3 and IBus | inline in the client | strans popup |
| XIM PreeditCallbacks | inline through XIM callbacks | strans popup |
| XIM PreeditPosition | strans popup | strans popup |
| XIM PreeditNothing | strans popup | strans popup |

XIM text travels as `COMPOUND_TEXT`, which carries any UTF-8. A client that
sends `XNSpotLocation` gets the popup at that spot whatever its preedit
style; otherwise the popup sits under the focus window, or under the client
window when no focus window is set.

The popup is an X11 window sized by `GDK_SCALE` on HiDPI displays, XIM is
X11-only, and GTK popup placement converts the GTK caret to X11 root
coordinates. There is no native Wayland popup surface or Wayland caret
positioning. GTK and IBus clients can still use inline preedit where their
display environment supports it.

## Build and test

Initialize the bundled test library, then use the pinned Docker environment
for a reproducible build:

```sh
git submodule update --init
make docker-image
make docker-build
```

Build output:

```text
strans              daemon with IBus and XIM frontends
gtk/im-strans.so    GTK 3 frontend module
```

Tests have three tiers:

```sh
make check          # generated-map validation and focused unit tests
make check-live     # one IBus, GTK, XIM, and IPC daemon smoke
make check-stress   # randomized, capacity, collision, failure, and restart tests
```

`UNITARGS` filters only the focused C unit suite, for example
`make check UNITARGS=hangul`. It does not select or skip live and stress
tests. `make docker-check` rebuilds and runs all three tiers in the
container, and `make docker-valgrind` runs the unit suite under Valgrind
there; run `make docker-image` first after changing `Dockerfile`.

Native Linux source builds require a C toolchain, Make, pkg-config, Python 3,
and cmp/diff, plus development files for:

- Plan 9 port (`9c`, `9l`, `libthread`, and `libbio`);
- D-Bus development files;
- XCB, XCB RandR, XCB XKB, xcb-imdkit, xkbcommon, and xkbcommon-x11;
- Pango, PangoCairo, Cairo, and Fontconfig;
- GTK 3, plus libibus and Xlib for the live clients;
- Xvfb for the X11 live tests;
- a working `C.UTF-8` locale and fonts covering Latin, CJK, and emoji.

The package names used by the canonical Arch Linux image are listed in
[`Dockerfile`](Dockerfile).

## Run

The popup uses the normal system fonts found by Pango and Fontconfig; no font
file argument or system-wide strans installation is required. Run it directly
from the build tree:

```sh
./run.sh
# equivalently
./strans map
```

`run.sh` stops every same-user process whose exact name is `strans`, starts one
build-tree daemon in the background, and returns to the shell. It requires
`pkill` from procps. Startup and frontend failures remain visible on the
caller's standard error. A service supervisor should instead run
`./strans map` directly in the foreground.

The build does not copy or install the daemon or its data. `./strans DIR`
opens `hira.map`, `kata.map`, `telex.map`, `kanji.dict`, `emoji.dict`, and
`hanja.dict` from `DIR` at runtime; `run.sh` passes the tracked `map/`
directory. Only the GTK subdirectory has install and uninstall targets.

Pango shapes the complete string and selects glyph fallback from the system
font set.

The popup renderer uses Pango/PangoCairo and Cairo. When `DISPLAY` is set,
`strans` starts its XIM worker in the same process.

Configure clients as needed:

```sh
# XIM
export XMODIFIERS=@im=strans

# GTK 3 module
doas make -C gtk install
export GTK_IM_MODULE=strans

# IBus client example
GLFW_IM_MODULE=ibus kitty
```

Building `gtk/im-strans.so` requires GTK development files. Installing an
already-built, up-to-date module from this build tree does not: the install
target first uses an explicit `GTK_MODULE_DIR`, then GTK's pkg-config
variables, and finally the module directory reported by the GTK runtime's
`gtk-query-immodules-3.0`. Packagers and cross builds should set
`GTK_MODULE_DIR` explicitly. A prebuilt module must still match the target
architecture and library ABI.

`DESTDIR` staging is supported and deliberately skips the host module-cache
update. A native install needs the GTK runtime query utility so it can refresh
that cache. Remove a native installation with:

```sh
doas make -C gtk uninstall
```

strans provides its own IBus endpoint; `ibus-daemon` and fcitx are not
required. Without `DISPLAY`, the daemon and IBus frontend still work, but XIM
is not started and the popup is disabled.

## Dictionary data

After changing an input source, regenerate and verify the dictionaries:

```sh
map/mkemoji >map/emoji.dict
map/mkhanja >map/hanja.dict
make verify-map
```

See [`map/README`](map/README) for Hanja import and Japanese dictionary
generation.

## Benchmark

`make bench` builds `bench/bench`. With the daemon stopped, `./bench.sh` starts
one build-tree instance, warms it up, and records the workload with Linux
`perf`. It requires `perf` and permission to profile the daemon, and writes
`bench/perf.data`.

## Licensing

Third-party license notices are in [`LICENSES`](LICENSES). The repository does
not currently declare a license for the strans source as a whole.