Backends: SDL2:+SDL2 Implement SetPlatformImeDataFn (amends). (#6071, #…

…1953)

backends/imgui_impl_sdl2.cpp

@@ -8,8 +8,7 @@
 //  [X] Platform: Keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy SDL_SCANCODE_* values will also be supported unless IMGUI_DISABLE_OBSOLETE_KEYIO is set]
 //  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
 //  [X] Platform: Mouse cursor shape and visibility. Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
-// Missing features:
-//  [ ] Platform: SDL2 handling of IME under Windows appears to be broken and it explicitly disable the regular Windows IME. You can restore Windows IME by compiling SDL with SDL_DISABLE_WINDOWS_IME.
+//  [X] Platform: Basic IME support. App needs to call 'SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");' before SDL_CreateWindow()!.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -18,6 +17,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2023-02-07: Implement IME handler (io.SetPlatformImeDataFn will call SDL_SetTextInputRect()/SDL_StartTextInput()).
 //  2023-02-07: *BREAKING CHANGE* Renamed this backend file from imgui_impl_sdl.cpp/.h to imgui_impl_sdl2.cpp/.h in prevision for the future release of SDL3.
 //  2023-02-02: Avoid calling SDL_SetCursor() when cursor has not changed, as the function is surprisingly costly on Mac with latest SDL (may be fixed in next SDL version).
 //  2023-02-02: Added support for SDL 2.0.18+ preciseX/preciseY mouse wheel data for smooth scrolling + Scaling X value on Emscripten (bug?). (#4019, #6096)
@@ -84,7 +84,6 @@
 #define SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE    0
 #endif
 #define SDL_HAS_VULKAN                      SDL_VERSION_ATLEAST(2,0,6)
-#define SDL_HAS_SET_TEXT_INPUT_RECT         SDL_VERSION_ATLEAST(2,0,0)
 
 // SDL Data
 struct ImGui_ImplSDL2_Data
@@ -127,6 +126,25 @@ static void ImGui_ImplSDL2_SetClipboardText(void*, const char* text)
     SDL_SetClipboardText(text);
 }
 
+// Note: native IME will only display if user calls SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1") _before_ SDL_CreateWindow().
+static void ImGui_ImplSDL2_SetPlatformImeData(ImGuiViewport*, ImGuiPlatformImeData* data)
+{
+    if (data->WantVisible)
+    {
+        SDL_Rect r;
+        r.x = (int)data->InputPos.x;
+        r.y = (int)data->InputPos.y;
+        r.w = 1;
+        r.h = (int)data->InputLineHeight;
+        SDL_SetTextInputRect(&r);
+        SDL_StartTextInput();
+    }
+    else
+    {
+        SDL_StopTextInput();
+    }
+}
+
 static ImGuiKey ImGui_ImplSDL2_KeycodeToImGuiKey(int keycode)
 {
     switch (keycode)
@@ -337,27 +355,6 @@ bool ImGui_ImplSDL2_ProcessEvent(const SDL_Event* event)
     return false;
 }
 
-#if SDL_HAS_SET_TEXT_INPUT_RECT
-static void ImGui_ImplSDL2_SetPlatformImeData(ImGuiViewport* viewport, ImGuiPlatformImeData* data)
-{
-    (void)viewport;
-    if (data->WantVisible)
-    {
-        SDL_Rect r;
-        r.x = (int)data->InputPos.x;
-        r.y = (int)data->InputPos.y;
-        r.w = 1;
-        r.h = (int)data->InputLineHeight;
-        SDL_SetTextInputRect(&r);
-        SDL_StartTextInput();
-    }
-    else
-    {
-        SDL_StopTextInput();
-    }
-}
-#endif
-
 static bool ImGui_ImplSDL2_Init(SDL_Window* window, SDL_Renderer* renderer)
 {
     ImGuiIO& io = ImGui::GetIO();
@@ -388,10 +385,7 @@ static bool ImGui_ImplSDL2_Init(SDL_Window* window, SDL_Renderer* renderer)
     io.SetClipboardTextFn = ImGui_ImplSDL2_SetClipboardText;
     io.GetClipboardTextFn = ImGui_ImplSDL2_GetClipboardText;
     io.ClipboardUserData = nullptr;
-
-#if SDL_HAS_SET_TEXT_INPUT_RECT
     io.SetPlatformImeDataFn = ImGui_ImplSDL2_SetPlatformImeData;
-#endif
 
     // Load mouse cursors
     bd->MouseCursors[ImGuiMouseCursor_Arrow] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_ARROW);
@@ -428,6 +422,13 @@ static bool ImGui_ImplSDL2_Init(SDL_Window* window, SDL_Renderer* renderer)
     SDL_SetHint(SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH, "1");
 #endif
 
+    // From 2.0.18: Enable native IME.
+    // IMPORTANT: This is used at the time of SDL_CreateWindow() so this will only affects secondary windows, if any.
+    // For the main window to be affected, your application needs to call this manually before calling SDL_CreateWindow().
+#ifdef SDL_HINT_IME_SHOW_UI
+    SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");
+#endif
+
     // From 2.0.22: Disable auto-capture, this is preventing drag and drop across multiple windows (see #5710)
 #ifdef SDL_HINT_MOUSE_AUTO_CAPTURE
     SDL_SetHint(SDL_HINT_MOUSE_AUTO_CAPTURE, "0");

backends/imgui_impl_sdl2.h

@@ -7,8 +7,7 @@
 //  [X] Platform: Keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy SDL_SCANCODE_* values will also be supported unless IMGUI_DISABLE_OBSOLETE_KEYIO is set]
 //  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
 //  [X] Platform: Mouse cursor shape and visibility. Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
-// Missing features:
-//  [ ] Platform: SDL2 handling of IME under Windows appears to be broken and it explicitly disable the regular Windows IME. You can restore Windows IME by compiling SDL with SDL_DISABLE_WINDOWS_IME.
+//  [X] Platform: Basic IME support. App needs to call 'SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");' before SDL_CreateWindow()!.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_sdl3.cpp

@@ -8,6 +8,8 @@
 //  [X] Platform: Keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy SDL_SCANCODE_* values will also be supported unless IMGUI_DISABLE_OBSOLETE_KEYIO is set]
 //  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
 //  [X] Platform: Mouse cursor shape and visibility. Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
+// Missing features:
+//  [x] Platform: Basic IME support. Position somehow broken in SDL3 + app needs to call 'SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");' before SDL_CreateWindow()!.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -75,6 +77,24 @@ static void ImGui_ImplSDL3_SetClipboardText(void*, const char* text)
     SDL_SetClipboardText(text);
 }
 
+static void ImGui_ImplSDL3_SetPlatformImeData(ImGuiViewport*, ImGuiPlatformImeData* data)
+{
+    if (data->WantVisible)
+    {
+        SDL_Rect r;
+        r.x = (int)data->InputPos.x;
+        r.y = (int)data->InputPos.y;
+        r.w = 1;
+        r.h = (int)data->InputLineHeight;
+        SDL_SetTextInputRect(&r);
+        SDL_StartTextInput();
+    }
+    else
+    {
+        SDL_StopTextInput();
+    }
+}
+
 static ImGuiKey ImGui_ImplSDL3_KeycodeToImGuiKey(int keycode)
 {
     switch (keycode)
@@ -310,6 +330,7 @@ static bool ImGui_ImplSDL3_Init(SDL_Window* window, SDL_Renderer* renderer)
     io.SetClipboardTextFn = ImGui_ImplSDL3_SetClipboardText;
     io.GetClipboardTextFn = ImGui_ImplSDL3_GetClipboardText;
     io.ClipboardUserData = nullptr;
+    io.SetPlatformImeDataFn = ImGui_ImplSDL3_SetPlatformImeData;
 
     // Load mouse cursors
     bd->MouseCursors[ImGuiMouseCursor_Arrow] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_ARROW);

backends/imgui_impl_sdl3.h

@@ -8,6 +8,8 @@
 //  [X] Platform: Keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy SDL_SCANCODE_* values will also be supported unless IMGUI_DISABLE_OBSOLETE_KEYIO is set]
 //  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
 //  [X] Platform: Mouse cursor shape and visibility. Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
+// Missing features:
+//  [x] Platform: Basic IME support. Position somehow broken in SDL3 + app needs to call 'SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");' before SDL_CreateWindow()!.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

docs/CHANGELOG.txt

@@ -98,6 +98,9 @@ All changes:
   for smooth scrolling as reported by SDL. (#4019, #6096)
 - Backends: SDL2: Avoid calling SDL_SetCursor() when cursor has not changed, as the function
   is surprisingly costly on Mac with latest SDL (may be fixed in next SDL version). (#6113)
+- Backends: SDL2: Implement IME handler to call SDL_SetTextInputRect()/SDL_StartTextInput().
+  It will only works with SDL 2.0.18+ if your code calls 'SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1")'
+  prior to calling SDL_CreateWindow(). Updated all examples accordingly. (#6071, #1953)
 - Backends: SDL3: Added experimental imgui_impl_sdl3.cpp backend. (#6146) [@dovker, @ocornut]
   SDL 3.0.0 has not yet been released, so it is possible that its specs/api will change before
   release. This backend is provided as a convenience for early adopters etc. We don't recommend

examples/example_sdl2_directx11/main.cpp

@@ -35,6 +35,11 @@ int main(int, char**)
         return -1;
     }
 
+    // From 2.0.18: Enable native IME.
+#ifdef SDL_HINT_IME_SHOW_UI
+    SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");
+#endif
+
     // Setup window
     SDL_WindowFlags window_flags = (SDL_WindowFlags)(SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
     SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL2+DirectX11 example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1280, 720, window_flags);

examples/example_sdl2_metal/main.mm

@@ -53,6 +53,9 @@ int main(int, char**)
     // Inform SDL that we will be using metal for rendering. Without this hint initialization of metal renderer may fail.
     SDL_SetHint(SDL_HINT_RENDER_DRIVER, "metal");
 
+    // Enable native IME.
+    SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");
+
     SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL+Metal example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1280, 720, SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
     if (window == NULL)
     {

examples/example_sdl2_opengl2/main.cpp

@@ -24,6 +24,11 @@ int main(int, char**)
         return -1;
     }
 
+    // From 2.0.18: Enable native IME.
+#ifdef SDL_HINT_IME_SHOW_UI
+    SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");
+#endif
+
     // Setup window
     SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
     SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);

examples/example_sdl2_opengl3/main.cpp

@@ -53,6 +53,11 @@ int main(int, char**)
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
 #endif
 
+    // From 2.0.18: Enable native IME.
+#ifdef SDL_HINT_IME_SHOW_UI
+    SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");
+#endif
+
     // Create window with graphics context
     SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
     SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);

examples/example_sdl2_sdlrenderer/main.cpp

@@ -27,6 +27,11 @@ int main(int, char**)
         return -1;
     }
 
+    // From 2.0.18: Enable native IME.
+#ifdef SDL_HINT_IME_SHOW_UI
+    SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");
+#endif
+
     // Create window with SDL_Renderer graphics context
     SDL_WindowFlags window_flags = (SDL_WindowFlags)(SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
     SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL2+SDL_Renderer example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1280, 720, window_flags);

examples/example_sdl2_vulkan/main.cpp

@@ -350,6 +350,11 @@ int main(int, char**)
         return -1;
     }
 
+    // From 2.0.18: Enable native IME.
+#ifdef SDL_HINT_IME_SHOW_UI
+    SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");
+#endif
+
     // Create window with Vulkan graphics context
     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);

examples/example_sdl3_opengl3/main.cpp

@@ -53,6 +53,9 @@ int main(int, char**)
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
 #endif
 
+    // Enable native IME.
+    SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");
+
     // Create window with graphics context
     SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
     SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);

examples/imgui_examples.sln

@@ -27,8 +27,6 @@ Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "example_sdl2_sdlrenderer",
 EndProject
 Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "example_sdl2_vulkan", "example_sdl2_vulkan\example_sdl2_vulkan.vcxproj", "{BAE3D0B5-9695-4EB1-AD0F-75890EB4A3B3}"
 EndProject
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "example_sdl3_opengl3", "example_sdl3_opengl3\example_sdl3_opengl3.vcxproj", "{84AAA301-84FE-428B-9E3E-817BC8123C0C}"
-EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Win32 = Debug|Win32
@@ -133,14 +131,6 @@ Global
 		{BAE3D0B5-9695-4EB1-AD0F-75890EB4A3B3}.Release|Win32.Build.0 = Release|Win32
 		{BAE3D0B5-9695-4EB1-AD0F-75890EB4A3B3}.Release|x64.ActiveCfg = Release|x64
 		{BAE3D0B5-9695-4EB1-AD0F-75890EB4A3B3}.Release|x64.Build.0 = Release|x64
-		{84AAA301-84FE-428B-9E3E-817BC8123C0C}.Debug|Win32.ActiveCfg = Debug|Win32
-		{84AAA301-84FE-428B-9E3E-817BC8123C0C}.Debug|Win32.Build.0 = Debug|Win32
-		{84AAA301-84FE-428B-9E3E-817BC8123C0C}.Debug|x64.ActiveCfg = Debug|x64
-		{84AAA301-84FE-428B-9E3E-817BC8123C0C}.Debug|x64.Build.0 = Debug|x64
-		{84AAA301-84FE-428B-9E3E-817BC8123C0C}.Release|Win32.ActiveCfg = Release|Win32
-		{84AAA301-84FE-428B-9E3E-817BC8123C0C}.Release|Win32.Build.0 = Release|Win32
-		{84AAA301-84FE-428B-9E3E-817BC8123C0C}.Release|x64.ActiveCfg = Release|x64
-		{84AAA301-84FE-428B-9E3E-817BC8123C0C}.Release|x64.Build.0 = Release|x64
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

imgui.cpp

@@ -4819,8 +4819,12 @@ void ImGui::EndFrame()
     ErrorCheckEndFrameSanityChecks();
 
     // Notify Platform/OS when our Input Method Editor cursor has moved (e.g. CJK inputs using Microsoft IME)
-    if (g.IO.SetPlatformImeDataFn && memcmp(&g.PlatformImeData, &g.PlatformImeDataPrev, sizeof(ImGuiPlatformImeData)) != 0)
-        g.IO.SetPlatformImeDataFn(GetMainViewport(), &g.PlatformImeData);
+    ImGuiPlatformImeData* ime_data = &g.PlatformImeData;
+    if (g.IO.SetPlatformImeDataFn && memcmp(ime_data, &g.PlatformImeDataPrev, sizeof(ImGuiPlatformImeData)) != 0)
+    {
+        IMGUI_DEBUG_LOG_IO("Calling io.SetPlatformImeDataFn(): WantVisible: %d, InputPos (%.2f,%.2f)\n", ime_data->WantVisible, ime_data->InputPos.x, ime_data->InputPos.y);
+        g.IO.SetPlatformImeDataFn(GetMainViewport(), ime_data);
+    }
 
     // Hide implicit/fallback "Debug" window if it hasn't been used
     g.WithinFrameScopeWithImplicitWindow = false;