https://bugs.kde.org/show_bug.cgi?id=527400
Bug ID: 527400
Summary: companion change needed in kdeconnect-android
Classification: Applications
Product: kdeconnect
Version First 26.08.2
Reported In:
Platform: Other
OS: Microsoft Windows
Status: REPORTED
Severity: critical
Priority: NOR
Component: desktop-application
Assignee: [email protected]
Reporter: [email protected]
Target Milestone: ---
Created attachment 197321
--> https://bugs.kde.org/attachment.cgi?id=197321&action=edit
companion change needed in kdeconnect-android
# Feature request (English, for KDE GitLab)
> Target repo: **kdeconnect-kde** (desktop); companion change required in
> **kdeconnect-android** (phone keyboard).
> Drafted from `kde-kbd-ime-switch.md`.
---
## Title
Feature request: option to send **committed text** (bypass IME) in the remote
keyboard / mousepad plugin
## Summary
Add an opt-in toggle — **"Send as committed text (bypass IME)"** — to the
remote keyboard (mousepad) plugin. When enabled, the phone sends
already-composed text as a single committed-string message instead of a stream
of key events, and the desktop inserts it by paste (or by Unicode char
injection) so the desktop Input Method Editor (IME) does **not** re-segment it.
This fixes garbled CJK (and other composable) input on Windows/desktop when
typing via the phone.
## Motivation / Problem
When the phone is used as a remote keyboard to type into a desktop application,
KDE Connect injects the characters as **individual key events**. On platforms
with an active IME — most visibly Windows with Microsoft Pinyin / Chinese,
Japanese, Korean, but the same class of bug applies anywhere an IME is in
composition state — those events are fed into the IME's composition buffer,
which **re-tokenizes and re-submits** the text. Observable consequences:
- Reordered characters (e.g. `为PVC主连写一个15分钟周期策略` becomes
`为PVC5分钟周期策略...主连写一个`).
- Dropped characters (`15` → `5`).
- Wrong candidates injected by the desktop IME.
There is currently **no way** to deliver already-composed final text through
the keyboard plugin; users must either (a) switch the desktop IME to English,
or (b) fall back to the clipboard plugin. Both are workarounds, not a real fix.
## Proposed solution
### 1. The toggle
- Name: `Send as committed text (bypass IME)`.
- Location: **phone-side** keyboard plugin settings (composition happens on the
phone, so the switch belongs there).
- Default: **off** (preserves current key-event behaviour and full support for
special keys / shortcuts).
- Scope: applies only to **text runs**; arrow keys, modifiers and shortcuts
continue to be sent as key events and are unaffected.
### 2. Behaviour when enabled
When the phone IME finishes a composition (commit), the plugin sends the
**final string** as one committed-text packet instead of a batch of key events.
### 3. Desktop-side handling (on receiving the committed-text packet)
- **Option A — clipboard + paste (recommended, cross-platform):** save current
clipboard → set clipboard to the string → send `Esc` (cancel any in-flight
composition) → send `Ctrl+V` → restore clipboard. Pasting bypasses IME
composition on Wayland, X11 and Windows.
- **Option B — Unicode char injection (cleaner on Windows):** on Windows use
`SendInput` with `KEYEVENTF_UNICODE` to deliver each character directly as
`WM_CHAR` (the IME will not re-compose it); on X11 use `XTest` with the
resolved Unicode keysym. Does not touch the clipboard and coexists with
special-key sending. Limitation: Wayland input injection is restricted, so
Option A is more reliable there.
### 4. Protocol / packet change
Extend the `kdeconnect.mousepad` packet:
- Add a `text` field carrying the committed UTF-8 string, plus a subtype/marker
distinguishing it from the existing key-event fields (`key` / `specialKey`),
**or**
- introduce a dedicated message type such as `kdeconnect.mousepad.string`.
Special keys must keep using the existing key-event path so shortcuts and
navigation keep working.
## Affected components
| Repo | Component
| Change
|
| -------------------- |
--------------------------------------------------------- |
-------------------------------------------------------------------------------------------------------------------
|
| `kdeconnect-android` | `plugins/keyboard` (remote keyboard
`InputMethodService`) | Add the settings toggle; on commit, when enabled, send
the committed-text packet instead of dispatching key events. |
| `kdeconnect-kde` | `plugins/mousepad`
| Add a receive branch for the committed-text packet implementing Option A
(and Option B on Windows). |
## Alternatives considered
1. **Tell users to use the clipboard plugin.** Already possible and IME-safe,
but less convenient than typing directly — it is a workaround, not a fix.
2. **Always paste instead of key events (change the default).** Breaks special
keys / shortcuts and is undesirable as a default.
3. **Fix it via OS / IME settings.** Out of KDE Connect's control and not
portable across users.
## Additional context (IME background)
An IME only re-composes input that arrives as **key events**. Final text
delivered as a **string** (paste, or `WM_CHAR`/`KEYEVENTF_UNICODE`) is never
re-tokenized, which is exactly why the clipboard-plugin path already works. The
proposed toggle essentially automates that safe path for the keyboard plugin.
## Possible implementation sketch (illustrative)
**Android (`plugins/keyboard`):**
```kotlin
// when the IME commits a composed string and the toggle is ON
if (prefs.bypassIme) {
val np = NetworkPacket(PACKET_TYPE_MOUSEPAD_STRING)
np["text"] = committedText
device.sendPacket(np)
} else {
// current behaviour: dispatch as key events
}
```
**Desktop (`plugins/mousepad`, C++ / Windows Option B):**
```cpp
// on receiving the committed-text packet
const QString text = np.get<QString>(QStringLiteral("text"));
INPUT inputs[1];
inputs[0].type = INPUT_KEYBOARD;
inputs[0].ki.wScan = text[0].unicode();
inputs[0].ki.dwFlags = KEYEVENTF_UNICODE; // delivered as WM_CHAR, IME won't
re-compose
SendInput(1, inputs, sizeof(INPUT));
// (loop per character; Option A uses clipboard + Ctrl+V instead)
```
## Environment where the bug is reproduced
- OS: Windows 10/11, display language Chinese (Simplified) — Microsoft Pinyin
IME active.
- KDE Connect: Microsoft Store build `26.801.6731.0` (x64); the bug is not
version-specific (it is inherent to key-event injection + active IME).
- Also affects other IME languages (JA/KO) and likely any desktop where an IME
is in composition state.
---
*Note: this is a feature request. A working implementation would need changes
in both `kdeconnect-android` and `kdeconnect-kde`; the sketches above are
illustrative, not a finished patch.*
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