Workaround to disable the incomplete UI-less mode IME in SDL(Windows)

examples/example_sdl_opengl2/main.cpp

@@ -21,6 +21,7 @@ int main(int, char**)
         printf("Error: %s\n", SDL_GetError());
         return -1;
     }
+    ImGui_ImplSDL2_Init();
 
     // Setup window
     SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
@@ -32,6 +33,7 @@ int main(int, char**)
     SDL_GetCurrentDisplayMode(0, &current);
     SDL_WindowFlags window_flags = (SDL_WindowFlags)(SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
     SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL2+OpenGL example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1280, 720, window_flags);
+    ImGui_ImplSDL2_HookIme(window);
     SDL_GLContext gl_context = SDL_GL_CreateContext(window);
     SDL_GL_SetSwapInterval(1); // Enable vsync
 

examples/example_sdl_opengl3/main.cpp

@@ -30,6 +30,7 @@ int main(int, char**)
         printf("Error: %s\n", SDL_GetError());
         return -1;
     }
+    ImGui_ImplSDL2_Init();
 
     // Decide GL+GLSL versions
 #if __APPLE__
@@ -56,6 +57,7 @@ int main(int, char**)
     SDL_GetCurrentDisplayMode(0, &current);
     SDL_WindowFlags window_flags = (SDL_WindowFlags)(SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
     SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL2+OpenGL3 example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1280, 720, window_flags);
+    ImGui_ImplSDL2_HookIme(window);
     SDL_GLContext gl_context = SDL_GL_CreateContext(window);
     SDL_GL_SetSwapInterval(1); // Enable vsync
 

examples/example_sdl_vulkan/main.cpp

@@ -304,12 +304,14 @@ int main(int, char**)
         printf("Error: %s\n", SDL_GetError());
         return 1;
     }
+    ImGui_ImplSDL2_Init();
 
     // Setup window
     SDL_DisplayMode current;
     SDL_GetCurrentDisplayMode(0, &current);
     SDL_WindowFlags window_flags = (SDL_WindowFlags)(SDL_WINDOW_VULKAN | SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
     SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL2+Vulkan example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1280, 720, window_flags);
+    ImGui_ImplSDL2_HookIme(window);
 
     // Setup Vulkan
     uint32_t extensions_count = 0;

examples/imgui_impl_sdl.cpp

@@ -60,6 +60,9 @@ static Uint64       g_Time = 0;
 static bool         g_MousePressed[3] = { false, false, false };
 static SDL_Cursor*  g_MouseCursors[ImGuiMouseCursor_COUNT] = { 0 };
 static char*        g_ClipboardTextData = NULL;
+static bool         g_PrevWantInputText = true;
+static int          g_ImeInputScreenPos[2] = { 0 , 0 };
+static int          g_NextImeInputScreenPos[2] = { 0 , 0 };
 
 static const char* ImGui_ImplSDL2_GetClipboardText(void*)
 {
@@ -74,6 +77,58 @@ static void ImGui_ImplSDL2_SetClipboardText(void*, const char* text)
     SDL_SetClipboardText(text);
 }
 
+static void ImGui_ImplSDL2_ImeSetInputScreenPos(int x, int y)
+{
+    g_NextImeInputScreenPos[0] = x;
+    g_NextImeInputScreenPos[1] = y;
+}
+
+#ifdef _WIN32
+static HWND ImGui_ImplSDL2_GetHWND(SDL_Window* window)
+{
+    SDL_SysWMinfo wmInfo;
+    SDL_VERSION(&wmInfo.version);
+    SDL_GetWindowWMInfo(window, &wmInfo);
+    return (HWND)wmInfo.info.win.window;
+}
+
+static LRESULT CALLBACK ImGui_ImplSDL2_HookIme_WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
+{
+    WNDPROC wndProc = (WNDPROC)GetWindowLongPtr(hwnd, GWLP_USERDATA);
+    switch (msg)
+    {
+    case WM_KEYDOWN:
+    case WM_SYSKEYDOWN:
+    case WM_KEYUP:
+    case WM_SYSKEYUP:
+        if (wParam == VK_PROCESSKEY)
+            wndProc = DefWindowProc;
+    }
+    return CallWindowProc(wndProc, hwnd, msg, wParam, lParam);
+}
+#endif
+
+void ImGui_ImplSDL2_Init()
+{
+#ifdef _WIN32
+    SDL_EventState(SDL_TEXTINPUT, SDL_DISABLE);
+#endif
+}
+
+void ImGui_ImplSDL2_HookIme(SDL_Window* window)
+{
+#ifdef _WIN32
+    HWND hwnd = ImGui_ImplSDL2_GetHWND(window);
+    if (!GetWindowLongPtr(hwnd, GWLP_USERDATA)) {
+        SetWindowLongPtr(hwnd, GWLP_USERDATA, GetWindowLongPtr(hwnd, GWLP_WNDPROC));
+        SetWindowLongPtr(hwnd, GWLP_WNDPROC, (LONG_PTR)ImGui_ImplSDL2_HookIme_WndProc);
+    }
+    ImmAssociateContext(hwnd, 0);
+    SDL_StartTextInput();
+    ImmAssociateContextEx(hwnd, 0, IACE_DEFAULT);
+#endif
+}
+
 // You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to use your inputs.
 // - When io.WantCaptureMouse is true, do not dispatch mouse input data to your main application.
 // - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application.
@@ -116,6 +171,15 @@ bool ImGui_ImplSDL2_ProcessEvent(const SDL_Event* event)
             io.KeySuper = ((SDL_GetModState() & KMOD_GUI) != 0);
             return true;
         }
+#ifdef _WIN32
+    case SDL_WINDOWEVENT:
+        if (event->window.event == SDL_WINDOWEVENT_FOCUS_GAINED && SDL_EventState(SDL_TEXTINPUT, SDL_QUERY))
+        {
+            SDL_Window* window = SDL_GetWindowFromID(event->window.windowID);
+            if (window)
+                ImmAssociateContextEx(ImGui_ImplSDL2_GetHWND(window), 0, IACE_DEFAULT);
+        }
+#endif
     }
     return false;
 }
@@ -156,6 +220,7 @@ static bool ImGui_ImplSDL2_Init(SDL_Window* window)
     io.SetClipboardTextFn = ImGui_ImplSDL2_SetClipboardText;
     io.GetClipboardTextFn = ImGui_ImplSDL2_GetClipboardText;
     io.ClipboardUserData = NULL;
+    io.ImeSetInputScreenPosFn = ImGui_ImplSDL2_ImeSetInputScreenPos;
 
     g_MouseCursors[ImGuiMouseCursor_Arrow] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_ARROW);
     g_MouseCursors[ImGuiMouseCursor_TextInput] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_IBEAM);
@@ -167,10 +232,7 @@ static bool ImGui_ImplSDL2_Init(SDL_Window* window)
     g_MouseCursors[ImGuiMouseCursor_Hand] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_HAND);
 
 #ifdef _WIN32
-    SDL_SysWMinfo wmInfo;
-    SDL_VERSION(&wmInfo.version);
-    SDL_GetWindowWMInfo(window, &wmInfo);
-    io.ImeWindowHandle = wmInfo.info.win.window;
+    io.ImeWindowHandle = ImGui_ImplSDL2_GetHWND(window);
 #else
     (void)window;
 #endif
@@ -268,6 +330,31 @@ static void ImGui_ImplSDL2_UpdateMouseCursor()
     }
 }
 
+static void ImGui_ImplSDL2_UpdateTextInput(SDL_Window* window)
+{
+    ImGuiIO& io = ImGui::GetIO();
+    if (io.WantTextInput != g_PrevWantInputText)
+    {
+        g_PrevWantInputText = io.WantTextInput;
+        if (io.WantTextInput)
+        {
+            SDL_StartTextInput();
+#ifdef _WIN32
+            ImmAssociateContextEx(ImGui_ImplSDL2_GetHWND(window), 0, IACE_DEFAULT);
+#endif
+        }
+        else
+            SDL_StopTextInput();
+    }
+    if (io.WantTextInput && (g_NextImeInputScreenPos[0] != g_ImeInputScreenPos[0] || g_NextImeInputScreenPos[1] != g_ImeInputScreenPos[1]))
+    {
+        g_ImeInputScreenPos[0] = g_NextImeInputScreenPos[0];
+        g_ImeInputScreenPos[1] = g_NextImeInputScreenPos[1];
+        SDL_Rect rect = { g_ImeInputScreenPos[0], g_ImeInputScreenPos[1], 0, 0 };
+        SDL_SetTextInputRect(&rect);
+    }
+}
+
 void ImGui_ImplSDL2_NewFrame(SDL_Window* window)
 {
     ImGuiIO& io = ImGui::GetIO();
@@ -289,4 +376,5 @@ void ImGui_ImplSDL2_NewFrame(SDL_Window* window)
 
     ImGui_ImplSDL2_UpdateMousePosAndButtons();
     ImGui_ImplSDL2_UpdateMouseCursor();
+    ImGui_ImplSDL2_UpdateTextInput(window);
 }

examples/imgui_impl_sdl.h

@@ -19,6 +19,8 @@
 struct SDL_Window;
 typedef union SDL_Event SDL_Event;
 
+IMGUI_IMPL_API void     ImGui_ImplSDL2_Init();
+IMGUI_IMPL_API void     ImGui_ImplSDL2_HookIme(SDL_Window* window);
 IMGUI_IMPL_API bool     ImGui_ImplSDL2_InitForOpenGL(SDL_Window* window, void* sdl_gl_context);
 IMGUI_IMPL_API bool     ImGui_ImplSDL2_InitForVulkan(SDL_Window* window);
 IMGUI_IMPL_API void     ImGui_ImplSDL2_Shutdown();