AppWindowParams: add EmscriptenKeyboardElement

pthom · Nov 23, 2024 · 68dc965 · 68dc965
1 parent 0542026
commit 68dc965
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diff --git a/src/hello_imgui/app_window_params.h b/src/hello_imgui/app_window_params.h
@@ -34,6 +34,16 @@ enum class WindowPositionMode
 };
 
 
+enum class EmscriptenKeyboardElement
+{
+    Window,
+    Document,
+    Screen,
+    Canvas,
+    Default
+};
+
+
 enum class WindowSizeMeasureMode
 {
     // ScreenCoords: measure window size in screen coords.
@@ -215,6 +225,18 @@ struct AppWindowParams
     // If true, HelloImGui will handle the edgeInsets on iOS.
     bool       handleEdgeInsets = true;
 
+
+    // --------------- Emscripten ------------------
+    // `emscriptenKeyboardElement`: _EmscriptenKeyboardElement, default=Default_. HTML element in which SDL will capture the keyboard events.
+    // (For Emscripten only)
+    // Choose between: Window, Document, Screen, Canvas, Default.
+    // If Default:
+    // - the default SDL behavior is used, which is to capture the keyboard events for the window,
+    //   if no previous hint was set in the javascript code.
+    // - under Pyodide, the default behavior is to capture the keyboard events for the canvas.
+    EmscriptenKeyboardElement emscriptenKeyboardElement = EmscriptenKeyboardElement::Default;
+
+
     // ----------------- repaint the window during resize -----------------
     // Very advanced and reserved for advanced C++ users.
     // If you set this to true, the window will be repainted during resize.

diff --git a/src/hello_imgui/internal/backend_impls/backend_window_helper/sdl_window_helper.cpp b/src/hello_imgui/internal/backend_impls/backend_window_helper/sdl_window_helper.cpp
@@ -130,6 +130,28 @@ namespace HelloImGui { namespace BackendApi
         SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");
         #endif
 
+        #ifdef __EMSCRIPTEN__
+        if (appWindowParams.emscriptenKeyboardElement == EmscriptenKeyboardElement::Window)
+            SDL_SetHint(SDL_HINT_EMSCRIPTEN_KEYBOARD_ELEMENT, "#window");
+        else if (appWindowParams.emscriptenKeyboardElement == EmscriptenKeyboardElement::Document)
+            SDL_SetHint(SDL_HINT_EMSCRIPTEN_KEYBOARD_ELEMENT, "#document");
+        else if (appWindowParams.emscriptenKeyboardElement == EmscriptenKeyboardElement::Screen)
+            SDL_SetHint(SDL_HINT_EMSCRIPTEN_KEYBOARD_ELEMENT, "#screen");
+        else if (appWindowParams.emscriptenKeyboardElement == EmscriptenKeyboardElement::Canvas)
+            SDL_SetHint(SDL_HINT_EMSCRIPTEN_KEYBOARD_ELEMENT, "#canvas");
+        else if (appWindowParams.emscriptenKeyboardElement == EmscriptenKeyboardElement::Default)
+        {
+            // If Default:
+            // - the default SDL behavior is used, which is to capture the keyboard events for the window,
+            //   if no previous hint was set in the javascript code.
+
+            // - under Pyodide, the default behavior is to capture the keyboard events for the canvas.
+            #ifdef IMGUI_BUNDLE_BUILD_PYODIDE
+            SDL_SetHint(SDL_HINT_EMSCRIPTEN_KEYBOARD_ELEMENT, "#canvas");
+            #endif
+        }
+        #endif // __EMSCRIPTEN__
+
         // If the window is created with the SDL_WINDOW_ALLOW_HIGHDPI flag,
         // its size in pixels may differ from its size in screen coordinates on platforms with high-DPI support
         // (e.g. iOS and macOS).