Build failure with fcitx5 5.1.x: `InputContext::virtualKeyEvent` no longer exists

[misaka19465]

Thanks for your fancy work on virtual keyboard.

I found a build failure when building current master against recent fcitx5.

Environment

• fcitx5-virtualkeyboard-ui commit: d451680
• fcitx5: 5.1.21
• GCC: 16.1.1
• Distribution: Arch Linux

Build Error

src/virtualkeygeneral.cpp:27:19: error: 'class fcitx::InputContext' has no member named 'virtualKeyEvent'; did you mean 'virtualKeyboardEvent'?
   27 |     inputContext->virtualKeyEvent(event);
      |                   ^~~~~~~~~~~~~~~
      |                   virtualKeyboardEvent

In recent fcitx5, InputContext::virtualKeyEvent(KeyEvent&) appears to have been replaced by InputContext::virtualKeyboardEvent(VirtualKeyboardEvent&).

The patch below updates NormalKey::click() to use VirtualKeyboardEvent and set the converted key explicitly.

Possible Solution

diff --git a/src/virtualkeygeneral.cpp b/src/virtualkeygeneral.cpp
index 1fd93ea..45f8633 100644
--- a/src/virtualkeygeneral.cpp
+++ b/src/virtualkeygeneral.cpp
@@ -23,8 +23,9 @@ void NormalKey::click(VirtualKeyboard *keyboard, InputContext *inputContext, boo
         keyboard->sendShiftModifierToIM(inputContext, false);
     }
 
-    auto event = KeyEvent(inputContext, convert(keyboard->isShiftOn()), isRelease);
-    inputContext->virtualKeyEvent(event);
+    auto event = VirtualKeyboardEvent(inputContext, isRelease);
+    event.setKey(convert(keyboard->isShiftOn()));
+    inputContext->virtualKeyboardEvent(event);
 
     if (keyboard->isShiftOn()) {
         keyboard->sendShiftModifierToIM(inputContext, true);

With this patch applied, the project builds successfully for the Wayland-only configuration against fcitx5 5.1.21.

[ashie]

Thank you for your report!

In fact, the InputContext::virtualKeyEvent function was not originally present in Fcitx5. This API was proposed by us in this pull request. As a result, as described in the README.md, the fcitx5-virtualkeyboard-ui can only be built using our forked version of Fcitx5.

With this patch applied, the project builds successfully for the Wayland-only configuration against fcitx5 5.1.21.

We are not currently aware of recent developments in Fcitx5, but if a similar API has been added and the build is truly possible with just this minor change, that would be excellent news!
At this time, we have not yet been able to build or test the software with the Fcitx5 5.1 series.
If you encounter any other issues, please feel free to report them at your convenience.

[misaka19465]

Thanks for the clarification and for pointing to the original PR.

I checked this against upstream fcitx5 tags. The original virtualKeyEvent PR indeed appears to be open:
fcitx/fcitx5#454

However, upstream fcitx5 does contain the similar InputContext::virtualKeyboardEvent(VirtualKeyboardEvent&) API, documented as @since 5.1.0:
https://github.com/fcitx/fcitx5/blob/5.1.0/src/lib/fcitx/inputcontext.h#L149-L154

VirtualKeyboardEvent also provides setKey(...), which is what the patch uses:
https://github.com/fcitx/fcitx5/blob/5.1.0/src/lib/fcitx/event.h#L378-L386

So this is not a case where virtualKeyEvent(KeyEvent&) was merged and renamed. Rather, upstream fcitx5 has a similar virtual keyboard API under the distinct virtualKeyboardEvent(VirtualKeyboardEvent&) interface, which seems sufficient for this code path.

So far I have only confirmed that the Wayland-only build succeeds with this change; I have not done broader runtime testing yet. I will report any other issues separately if I find them.