Follow Plasma's virtual keyboard setting

KWin activates the input method for every text field; its policy (the
tray toggle) only gates the input panel, which sloposk doesn't use. sloposk
now asks KWin over D-Bus whether a focused field should show the
keyboard: never when off, only after touch or a pen by default.
"Always Show" and D-Bus Show/Toggle still show it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/CMakeLists.txt

@@ -81,6 +81,7 @@ qt_add_executable(sloposk
     app/DevHooks.h app/DevHooks.cpp
     app/DBusControl.h app/DBusControl.cpp
     app/Checks.h app/Checks.cpp
+    app/KWinVirtualKeyboard.h app/KWinVirtualKeyboard.cpp
     app/QuitOnSignal.h app/QuitOnSignal.cpp
     app/SystemLayouts.h app/SystemLayouts.cpp
     backend/InputMethodProtocol.h

src/app/KWinVirtualKeyboard.cpp

@@ -0,0 +1,30 @@
+#include "KWinVirtualKeyboard.h"
+
+#include <QDBusConnection>
+#include <QDBusMessage>
+#include <QDBusPendingCallWatcher>
+#include <QDBusPendingReply>
+
+namespace {
+const QString Service = QStringLiteral("org.kde.KWin");
+const QString Path = QStringLiteral("/VirtualKeyboard");
+const QString Interface = QStringLiteral("org.kde.kwin.VirtualKeyboard");
+} // namespace
+
+KWinVirtualKeyboard::KWinVirtualKeyboard(QObject *parent)
+    : QObject(parent)
+{
+    QDBusConnection::sessionBus().connect(Service, Path, Interface, QStringLiteral("modeChanged"), this,
+                                          SIGNAL(modeChanged()));
+}
+
+void KWinVirtualKeyboard::askShowOnActive(QObject *context, std::function<void(bool)> answer)
+{
+    const QDBusMessage call = QDBusMessage::createMethodCall(Service, Path, Interface, QStringLiteral("willShowOnActive"));
+    auto *watcher = new QDBusPendingCallWatcher(QDBusConnection::sessionBus().asyncCall(call), context);
+    connect(watcher, &QDBusPendingCallWatcher::finished, context, [answer = std::move(answer)](QDBusPendingCallWatcher *watcher) {
+        watcher->deleteLater();
+        const QDBusPendingReply<bool> reply = *watcher;
+        answer(reply.isError() || reply.value());
+    });
+}

src/app/KWinVirtualKeyboard.h

@@ -0,0 +1,25 @@
+#pragma once
+
+#include <QObject>
+
+#include <functional>
+
+// KWin's virtual keyboard policy (the tray toggle, System Settings →
+// Virtual Keyboard): KWin activates the input method for every text field
+// and the policy only gates its input panel, which sloposk doesn't use, so
+// sloposk asks it over org.kde.KWin /VirtualKeyboard instead.
+class KWinVirtualKeyboard : public QObject
+{
+    Q_OBJECT
+
+public:
+    explicit KWinVirtualKeyboard(QObject *parent = nullptr);
+
+    // Calls `answer` with whether a field focused now should show the
+    // keyboard: never when it's off, only after touch or a pen in the
+    // default mode. True if KWin can't be asked.
+    void askShowOnActive(QObject *context, std::function<void(bool)> answer);
+
+Q_SIGNALS:
+    void modeChanged();
+};

src/main.cpp

@@ -1,6 +1,7 @@
 #include "app/Checks.h"
 #include "app/DBusControl.h"
 #include "app/DevHooks.h"
+#include "app/KWinVirtualKeyboard.h"
 #include "app/QuitOnSignal.h"
 #include "app/SystemLayouts.h"
 #include "backend/KWinInputMethod.h"
@@ -89,6 +90,27 @@ void restoreAndPersistGeometry(FloatingWindow &placement, WindowSettings &settin
                      [&] { settings.save(placement.screenName(), placement.geometry()); });
 }
 
+// A focused field shows the keyboard only if KWin's policy wants one now;
+// asked before showing, so a "no" doesn't flash the keyboard.
+void connectFieldFocus(VisibilityController &visibility, KWinInputMethod &backend, KWinVirtualKeyboard &policy)
+{
+    QObject::connect(&backend, &TextBackend::activeChanged, &visibility, [&] {
+        if (!backend.isActive()) {
+            visibility.setFieldActive(false);
+            return;
+        }
+        policy.askShowOnActive(&visibility, [&](bool show) {
+            if (!backend.isActive())
+                return; // left the field before KWin answered
+            visibility.setShowOnField(show);
+            visibility.setFieldActive(true);
+        });
+    });
+    QObject::connect(&policy, &KWinVirtualKeyboard::modeChanged, &visibility, [&] {
+        policy.askShowOnActive(&visibility, [&](bool show) { visibility.setShowOnField(show); });
+    });
+}
+
 void connectVisibility(VisibilityController &visibility, KWinInputMethod &backend, const Settings &settings,
                        KeyboardController &controller, FloatingWindow &placement)
 {
@@ -99,8 +121,6 @@ void connectVisibility(VisibilityController &visibility, KWinInputMethod &backen
     // work) there is no focus signal: stay visible so it can be tried out.
     const auto updateStandalone = [&] { visibility.setStandalone(!backend.isAvailable()); };
     QObject::connect(&backend, &KWinInputMethod::availableChanged, &visibility, updateStandalone);
-    QObject::connect(&backend, &TextBackend::activeChanged, &visibility,
-                     [&] { visibility.setFieldActive(backend.isActive()); });
     QObject::connect(&controller, &KeyboardController::dismissRequested, &visibility, &VisibilityController::hide);
     QObject::connect(&visibility, &VisibilityController::visibleChanged, &placement,
                      [&](bool visible) { visible ? placement.show() : placement.hide(); });
@@ -175,6 +195,8 @@ int main(int argc, char *argv[])
     connectKeySettings(settings, model, placement, *window, rebuildLayout);
 
     VisibilityController visibility;
+    KWinVirtualKeyboard virtualKeyboardPolicy;
+    connectFieldFocus(visibility, backend, virtualKeyboardPolicy);
     connectVisibility(visibility, backend, settings, controller, placement);
 
     DBusControl dbus(visibility);

src/window/VisibilityController.cpp

@@ -7,6 +7,12 @@ void VisibilityController::setFieldActive(bool active)
     update();
 }
 
+void VisibilityController::setShowOnField(bool show)
+{
+    m_showOnField = show;
+    update();
+}
+
 void VisibilityController::setStandalone(bool standalone)
 {
     m_standalone = standalone;
@@ -40,7 +46,7 @@ void VisibilityController::toggle()
 
 void VisibilityController::update()
 {
-    const bool visible = m_override.value_or(m_alwaysVisible || m_standalone || m_fieldActive);
+    const bool visible = m_override.value_or(m_alwaysVisible || m_standalone || (m_fieldActive && m_showOnField));
     if (visible == m_visible)
         return;
     m_visible = visible;

src/window/VisibilityController.h

@@ -4,7 +4,7 @@
 #include <optional>
 
 // Decides whether the keyboard is shown:
-//  - while a text field is focused
+//  - while a text field is focused, if the system wants a keyboard for it
 //  - always, if the user wants it (to type into any window) or when running
 //    standalone (no input-method connection)
 //  - show()/hide()/toggle() override that until the focus changes, also
@@ -20,6 +20,8 @@ public:
 
     // Called on every focus change, even when a field follows a field.
     void setFieldActive(bool active);
+    // KWin's policy (off, or touch only) for fields focused from now on.
+    void setShowOnField(bool show);
     void setStandalone(bool standalone);
     void setAlwaysVisible(bool always);
 
@@ -34,6 +36,7 @@ private:
     void update();
 
     bool m_fieldActive = false;
+    bool m_showOnField = true;
     bool m_standalone = false;
     bool m_alwaysVisible = false;
     std::optional<bool> m_override;