Qt: Open host input method on imgui text edit

This should open virtual keyboards on devices which do not have a
physical keyboard.

pcsx2-qt/QtHost.cpp

@@ -52,6 +52,7 @@
 #include <QtWidgets/QApplication>
 #include <QtWidgets/QMessageBox>
 #include <QtGui/QClipboard>
+#include <QtGui/QInputMethod>
 
 #include "fmt/core.h"
 
@@ -1407,6 +1408,20 @@ bool Host::CopyTextToClipboard(const std::string_view& text)
 	return true;
 }
 
+void Host::BeginTextInput()
+{
+	QInputMethod* method = qApp->inputMethod();
+	if (method)
+		QMetaObject::invokeMethod(method, "show", Qt::QueuedConnection);
+}
+
+void Host::EndTextInput()
+{
+	QInputMethod* method = qApp->inputMethod();
+	if (method)
+		QMetaObject::invokeMethod(method, "hide", Qt::QueuedConnection);
+}
+
 void Host::OnInputDeviceConnected(const std::string_view& identifier, const std::string_view& device_name)
 {
 	emit g_emu_thread->onInputDeviceConnected(

pcsx2/Frontend/ImGuiManager.cpp

@@ -82,6 +82,7 @@ static Common::Timer s_last_render_time;
 // cached copies of WantCaptureKeyboard/Mouse, used to know when to dispatch events
 static std::atomic_bool s_imgui_wants_keyboard{false};
 static std::atomic_bool s_imgui_wants_mouse{false};
+static std::atomic_bool s_imgui_wants_text{false};
 
 // mapping of host key -> imgui key
 static std::unordered_map<u32, ImGuiKey> s_imgui_key_map;
@@ -225,6 +226,16 @@ void ImGuiManager::NewFrame()
 	ImGui::GetCurrentWindowRead()->Flags |= ImGuiWindowFlags_NoNavInputs;
 	s_imgui_wants_keyboard.store(io.WantCaptureKeyboard, std::memory_order_relaxed);
 	s_imgui_wants_mouse.store(io.WantCaptureMouse, std::memory_order_release);
+
+	const bool want_text_input = io.WantTextInput;
+	if (s_imgui_wants_text.load(std::memory_order_relaxed) != want_text_input)
+	{
+		s_imgui_wants_text.store(want_text_input, std::memory_order_release);
+		if (want_text_input)
+			Host::BeginTextInput();
+		else
+			Host::EndTextInput();
+	}
 #endif
 }
 
@@ -875,12 +886,12 @@ ImFont* ImGuiManager::GetLargeFont()
 
 bool ImGuiManager::WantsTextInput()
 {
-	return s_imgui_wants_keyboard.load(std::memory_order_acquire);
+	return s_imgui_wants_text.load(std::memory_order_acquire);
 }
 
 void ImGuiManager::AddTextInput(std::string str)
 {
-	if (!s_imgui_wants_keyboard.load(std::memory_order_acquire))
+	if (!s_imgui_wants_text.load(std::memory_order_acquire))
 		return;
 
 	// Has to go through the CPU -> GS thread :(

pcsx2/Frontend/ImGuiManager.h

@@ -90,3 +90,12 @@ namespace ImGuiManager
 #endif
 } // namespace ImGuiManager
 
+namespace Host
+{
+	/// Called by ImGuiManager when the cursor enters a text field. The host may choose to open an on-screen
+	/// keyboard for devices without a physical keyboard.
+	void BeginTextInput();
+
+	/// Called by ImGuiManager when the cursor leaves a text field.
+	void EndTextInput();
+}