WinRT: allow on-screen keyboard to be shown via SDL APIs, Win10/UWP only

src/video/winrt/SDL_winrtevents_c.h

@@ -67,6 +67,13 @@ extern void WINRT_ProcessKeyDownEvent(Windows::UI::Core::KeyEventArgs ^args);
 extern void WINRT_ProcessKeyUpEvent(Windows::UI::Core::KeyEventArgs ^args);
 extern void WINRT_ProcessCharacterReceivedEvent(Windows::UI::Core::CharacterReceivedEventArgs ^args);
 
+#if NTDDI_VERSION >= NTDDI_WIN10
+extern SDL_bool WINRT_HasScreenKeyboardSupport(_THIS);
+extern void WINRT_ShowScreenKeyboard(_THIS, SDL_Window *window);
+extern void WINRT_HideScreenKeyboard(_THIS, SDL_Window *window);
+extern SDL_bool WINRT_IsScreenKeyboardShown(_THIS, SDL_Window *window);
+#endif  // NTDDI_VERSION >= ...
+
 /* XAML Thread Management */
 extern void WINRT_CycleXAMLThread();
 

src/video/winrt/SDL_winrtkeyboard.cpp

@@ -383,4 +383,48 @@ WINRT_ProcessCharacterReceivedEvent(Windows::UI::Core::CharacterReceivedEventArg
     }
 }
 
+
+#if NTDDI_VERSION >= NTDDI_WIN10
+
+SDL_bool WINRT_HasScreenKeyboardSupport(_THIS)
+{
+    return SDL_TRUE;
+}
+
+void WINRT_ShowScreenKeyboard(_THIS, SDL_Window *window)
+{
+    using namespace Windows::UI::ViewManagement;
+    InputPane ^ inputPane = InputPane::GetForCurrentView();
+    if (inputPane) {
+        inputPane->TryShow();
+    }
+}
+
+void WINRT_HideScreenKeyboard(_THIS, SDL_Window *window)
+{
+    using namespace Windows::UI::ViewManagement;
+    InputPane ^ inputPane = InputPane::GetForCurrentView();
+    if (inputPane) {
+        inputPane->TryHide();
+    }
+}
+
+SDL_bool WINRT_IsScreenKeyboardShown(_THIS, SDL_Window *window)
+{
+    using namespace Windows::UI::ViewManagement;
+    InputPane ^ inputPane = InputPane::GetForCurrentView();
+    if (inputPane) {
+        // [email protected]: checking inputPane->Visible doesn't seem to detect visibility,
+        //   at least not on the Windows Phone 10.0.10240.0 emulator.  Checking
+        //   the size of inputPane->OccludedRect, however, does seem to work.
+        Windows::Foundation::Rect rect = inputPane->OccludedRect;
+        if (rect.Width > 0 && rect.Height > 0) {
+            return SDL_TRUE;
+        }
+    }
+    return SDL_FALSE;
+}
+
+#endif  // NTDDI_VERSION >= ...
+
 #endif // SDL_VIDEO_DRIVER_WINRT

src/video/winrt/SDL_winrtvideo.cpp

@@ -140,6 +140,14 @@ WINRT_CreateDevice(int devindex)
     device->SetDisplayMode = WINRT_SetDisplayMode;
     device->PumpEvents = WINRT_PumpEvents;
     device->GetWindowWMInfo = WINRT_GetWindowWMInfo;
+
+#if NTDDI_VERSION >= NTDDI_WIN10
+    device->HasScreenKeyboardSupport = WINRT_HasScreenKeyboardSupport;
+    device->ShowScreenKeyboard = WINRT_ShowScreenKeyboard;
+    device->HideScreenKeyboard = WINRT_HideScreenKeyboard;
+    device->IsScreenKeyboardShown = WINRT_IsScreenKeyboardShown;
+#endif
+
 #ifdef SDL_VIDEO_OPENGL_EGL
     device->GL_LoadLibrary = WINRT_GLES_LoadLibrary;
     device->GL_GetProcAddress = WINRT_GLES_GetProcAddress;