Platform: expose key scan codes and related APIs.

Unlike the Key enum, which shows what a user would perceive as given key
in a particular layout, the scancode is a layout-independent identifier
for e.g. WASD movement in games.

Unfortunately the API availability is wildly different among the
toolkits -- SDL's is the most complete, GLFW is second, and then there's
Emscripten / HTML5 which provides just string identifiers. I tried to
add these for X11 as well, but quick googling led to a SO question where
it was left unanswered. Not worth my time.

doc/changelog.dox

@@ -827,6 +827,16 @@ See also:
 -   Added more keys to @ref Platform::AbstractXApplication::KeyEvent::Key and
     implemented @ref Platform::AbstractXApplication::scrollEvent() for better
     consistency with other application implementations
+-   Added @ref Platform::Sdl2Application::KeyEvent::scanCode(),
+    @relativeref{Platform::Sdl2Application::KeyEvent,scanCodeName()},
+    @ref Platform::GlfwApplication::KeyEvent::scanCode() and
+    @ref Platform::EmscriptenApplication::KeyEvent::scanCodeName() for querying
+    layout-independent key identifiers as well as
+    @ref Platform::Sdl2Application::scanCodeName(UnsignedInt),
+    @relativeref{Platform::Sdl2Application,keyToScanCode()},
+    @relativeref{Platform::Sdl2Application,scanCodeToKey()} and
+    @ref Platform::GlfwApplication::keyToScanCode() helpers for key / scan code
+    conversion outside of event handlers
 
 @subsubsection changelog-latest-changes-scenegraph SceneGraph library
 
@@ -1423,12 +1433,14 @@ See also:
     wrappers as well.
 -   @cpp Platform::Sdl2Application::InputEvent::Modifier @ce,
     @cpp Modifiers @ce and @cpp Platform::Sdl2Application::KeyEvent::Key @ce
-    enums are deprecated in favor of @ref Platform::Sdl2Application::Modifier,
-    @relativeref{Platform::Sdl2Application,Modifiers} and
-    @relativeref{Platform::Sdl2Application,Key} enums contained directly in
-    the application class. Besides the obvious advantage of them being shorter
-    to type, this allows them to be used outside of the event class scope. The
-    same change is done in @ref Platform::AbstractXApplication,
+    enums and the @cpp Platform::Sdl2Application::KeyEvent::keyName(Key) @ce
+    function are deprecated in favor of @ref Platform::Sdl2Application::Modifier,
+    @relativeref{Platform::Sdl2Application,Modifiers},
+    @relativeref{Platform::Sdl2Application,Key} and
+    @relativeref{Platform::Sdl2Application,keyName()} APIs contained directly
+    in the application class. Besides the obvious advantage of them being
+    shorter to type, this allows the enums to be used outside of the event
+    class scope. The same change is done in @ref Platform::AbstractXApplication,
     @ref Platform::EmscriptenApplication and @ref Platform::GlfwApplication.
 -   @cpp Platform::AbstractXApplication::MouseEvent::Button::WheelUp @ce and
     `WheelDown` members are deprecated in favor of a dedicated

src/Magnum/Platform/EmscriptenApplication.cpp

@@ -1283,6 +1283,10 @@ Containers::StringView EmscriptenApplication::KeyEvent::keyName() const {
     return _event.code;
 }
 
+Containers::StringView EmscriptenApplication::KeyEvent::scanCodeName() const {
+    return _event.code;
+}
+
 EmscriptenApplication::Modifiers EmscriptenApplication::KeyEvent::modifiers() const {
     return eventModifiers(_event);
 }

src/Magnum/Platform/EmscriptenApplication.h

@@ -2456,23 +2456,43 @@ class EmscriptenApplication::KeyEvent: public EmscriptenApplication::InputEvent
         /**
          * @brief Key
          *
-         * Note that the key is mapped from @m_class{m-doc-external}
+         * Layout-dependent name of given key. Mapped from @m_class{m-doc-external}
          * [EmscriptenKeyboardEvent::code](https://emscripten.org/docs/api_reference/html5.h.html#c.EmscriptenKeyboardEvent.code)
          * in all cases except A--Z, which are mapped from
          * @m_class{m-doc-external} [EmscriptenkeyboardEvent::key](https://emscripten.org/docs/api_reference/html5.h.html#c.EmscriptenKeyboardEvent.key),
-         * which respects the keyboard layout.
+         * which respects the keyboard layout. Note that, unlike e.g.
+         * @ref Sdl2Application::KeyEvent::scanCode(), there's no numeric
+         * layout-independent identifier of given key, you have to use
+         * @ref scanCodeName() instead.
          */
         EmscriptenApplication::Key key() const;
 
         /**
          * @brief Key name
          *
-         * The returned view is always
+         * Layout-dependent name of given key. Returns
+         * @m_class{m-doc-external} [EmscriptenkeyboardEvent::key](https://emscripten.org/docs/api_reference/html5.h.html#c.EmscriptenKeyboardEvent.key)
+         * for keys A--Z and @m_class{m-doc-external} [EmscriptenKeyboardEvent::code](https://emscripten.org/docs/api_reference/html5.h.html#c.EmscriptenKeyboardEvent.code)
+         * for other keys, the view is always
          * @relativeref{Corrade,Containers::StringViewFlag::NullTerminated} and
-         * is valid until the event is destroyed.
+         * is valid until the event is destroyed. Use @ref scanCodeName() to
+         * get a platform-specific but layout-independent identifier of given
+         * key.
          */
         Containers::StringView keyName() const;
 
+        /**
+         * @brief Scancode name
+         * @m_since_latest
+         *
+         * Platform-specific but layout-independent identifier of given key.
+         * Returns @m_class{m-doc-external} [EmscriptenKeyboardEvent::code](https://emscripten.org/docs/api_reference/html5.h.html#c.EmscriptenKeyboardEvent.code),
+         * the view is always @relativeref{Corrade,Containers::StringViewFlag::NullTerminated}
+         * and is valid until the event is destroyed. Use @ref keyName() to get
+         * a key name in the currently used layout.
+         */
+        Containers::StringView scanCodeName() const;
+
         /** @brief Modifiers */
         EmscriptenApplication::Modifiers modifiers() const;
 

src/Magnum/Platform/GlfwApplication.cpp

@@ -662,10 +662,10 @@ void GlfwApplication::setupCallbacks() {
         #endif
         app.viewportEvent(e);
     });
-    glfwSetKeyCallback(_window, [](GLFWwindow* const window, const int key, int, const int action, const int mods) {
+    glfwSetKeyCallback(_window, [](GLFWwindow* const window, const int key, const int scancode, const int action, const int mods) {
         auto& app = *static_cast<GlfwApplication*>(glfwGetWindowUserPointer(window));
 
-        KeyEvent e(Key(key), Modifiers{mods}, action == GLFW_REPEAT);
+        KeyEvent e(Key(key), scancode, Modifiers{mods}, action == GLFW_REPEAT);
 
         if(action == GLFW_PRESS || action == GLFW_REPEAT)
             app.keyPressEvent(e);
@@ -741,6 +741,19 @@ GlfwApplication::~GlfwApplication() {
     glfwTerminate();
 }
 
+Containers::StringView GlfwApplication::keyName(const Key key, const UnsignedInt scancode) const {
+    return glfwGetKeyName(int(key), scancode);
+}
+
+#if GLFW_VERSION_MAJOR*100 + GLFW_VERSION_MINOR >= 303
+Containers::Optional<UnsignedInt> GlfwApplication::keyToScanCode(const Key key) const {
+    const int scancode = glfwGetKeyScancode(int(key));
+    if(scancode == -1)
+        return {};
+    return UnsignedInt(scancode);
+}
+#endif
+
 Vector2i GlfwApplication::windowSize() const {
     CORRADE_ASSERT(_window, "Platform::GlfwApplication::windowSize(): no window opened", {});
 
@@ -1107,12 +1120,14 @@ GlfwApplication::Configuration::Configuration():
 
 GlfwApplication::Configuration::~Configuration() = default;
 
+#ifdef MAGNUM_BUILD_DEPRECATED
 Containers::StringView GlfwApplication::KeyEvent::keyName(const GlfwApplication::Key key) {
     return glfwGetKeyName(int(key), 0);
 }
+#endif
 
 Containers::StringView GlfwApplication::KeyEvent::keyName() const {
-    return keyName(_key);
+    return glfwGetKeyName(Int(_key), _scancode);
 }
 
 GlfwApplication::Pointers GlfwApplication::PointerMoveEvent::pointers() {

src/Magnum/Platform/GlfwApplication.h

@@ -276,6 +276,43 @@ class GlfwApplication {
         /** @brief Moving is not allowed */
         GlfwApplication& operator=(GlfwApplication&&) = delete;
 
+        /**
+         * @brief Name for given key
+         * @m_since_latest
+         *
+         * Human-readable localized UTF-8 name for given @p key, intended for
+         * displaying to the user in e.g. a key binding configuration. For
+         * @ref Key::Unknown, a concrete @p scanCode can be passed. If there is
+         * no name for given key, an empty string is returned. If non-empty,
+         * the returned view is always
+         * @relativeref{Corrade,Containers::StringViewFlag::NullTerminated} and
+         * is valid until the keyboard layout is changed or the application
+         * exits.
+         *
+         * Unlike e.g. @ref Sdl2Application::keyName(), the function isn't
+         * @cpp static @ce because it relies on GLFW being initialized.
+         * @see @ref KeyEvent::keyName(), @ref keyToScanCode()
+         */
+        Containers::StringView keyName(Key key, UnsignedInt scanCode = 0) const;
+
+        #if GLFW_VERSION_MAJOR*100 + GLFW_VERSION_MINOR >= 303 || defined(DOXYGEN_GENERATING_OUTPUT)
+        /**
+         * @brief Scan code for given key
+         * @m_since_latest
+         *
+         * If @p key doesn't correspond to a physical key supported on given
+         * platform, returns @relativeref{Corrade,Containers::NullOpt}. Unlike
+         * e.g. @ref Sdl2Application::scanCodeToKey(), GLFW doesn't provide any
+         * way to map from a scan code to a key.
+         *
+         * Unlike e.g. @ref Sdl2Application::keyToScanCode(), the function
+         * isn't @cpp static @ce because it relies on GLFW being initialized.
+         * @note Available since GLFW 3.3.
+         * @see @ref KeyEvent::key(), @ref KeyEvent::scanCode(), @ref keyName()
+         */
+        Containers::Optional<UnsignedInt> keyToScanCode(Key key) const;
+        #endif
+
         /**
          * @brief Execute main loop
          * @return Value for returning from @cpp main() @ce
@@ -2090,33 +2127,42 @@ class GlfwApplication::KeyEvent: public GlfwApplication::InputEvent {
          * @m_deprecated_since_latest Use @ref GlfwApplication::Key instead.
          */
         typedef CORRADE_DEPRECATED("use GlfwApplication::Key instead") GlfwApplication::Key Key;
+
+        /**
+         * @brief @copybrief GlfwApplication::keyName()
+         * @m_deprecated_since_latest Use @ref GlfwApplication::keyName()
+         *      instead.
+         */
+        CORRADE_DEPRECATED("use GlfwApplication::keyName() instead") static Containers::StringView keyName(GlfwApplication::Key key);
         #endif
 
         /**
-         * @brief Name for given key
+         * @brief Key
          *
-         * Human-readable localized UTF-8 name for given @p key, intended for
-         * displaying to the user in e.g. key binding configuration. If there
-         * is no name for given key, empty string is returned. The returned
-         * view is always @relativeref{Corrade,Containers::StringViewFlag::NullTerminated}
-         * and is valid until the keyboard layout is changed or the application
-         * exits.
-         * @see @ref keyName(Key)
+         * Layout-dependent name of given key. Use @ref scanCode() to get a
+         * platform-specific but layout-independent identifier of given key.
+         * @see @ref keyName() const
          */
-        static Containers::StringView keyName(GlfwApplication::Key key);
-
-        /** @copydoc Sdl2Application::KeyEvent::key() */
         GlfwApplication::Key key() const { return _key; }
 
+        /**
+         * @brief Scancode
+         * @m_since_latest
+         *
+         * Platform-specific but layout-independent identifier of given key.
+         * Use @ref key() to get a key name in the currently used layout.
+         */
+        UnsignedInt scanCode() const { return _scancode; }
+
         /**
          * @brief Key name
          *
          * Human-readable localized UTF-8 name for the key returned by
-         * @ref key(), intended for displaying to the user in e.g.
-         * key binding configuration. If there is no name for that key, empty
-         * string is returned. The returned view is always
-         * @relativeref{Corrade,Containers::StringViewFlag::NullTerminated} and
-         * is valid until the keyboard layout is changed or the application
+         * @ref key() and @ref scanCode(), intended for displaying to the user
+         * in e.g. key binding configuration. If there is no name for that key,
+         * an empty string is returned. If non-empty, the returned view is
+         * always @relativeref{Corrade,Containers::StringViewFlag::NullTerminated}
+         * and is valid until the keyboard layout is changed or the application
          * exits.
          * @see @ref keyName(Key)
          */
@@ -2131,11 +2177,12 @@ class GlfwApplication::KeyEvent: public GlfwApplication::InputEvent {
     private:
         friend GlfwApplication;
 
-        explicit KeyEvent(GlfwApplication::Key key, GlfwApplication::Modifiers modifiers, bool repeated): _key{key}, _modifiers{modifiers}, _repeated{repeated} {}
+        explicit KeyEvent(GlfwApplication::Key key, UnsignedInt scancode, GlfwApplication::Modifiers modifiers, bool repeated): _repeated{repeated}, _modifiers{modifiers}, _key{key}, _scancode{scancode} {}
 
-        const GlfwApplication::Key _key;
-        const GlfwApplication::Modifiers _modifiers;
         const bool _repeated;
+        const GlfwApplication::Modifiers _modifiers;
+        const GlfwApplication::Key _key;
+        const UnsignedInt _scancode;
 };
 
 /**

src/Magnum/Platform/Sdl2Application.cpp

@@ -121,6 +121,34 @@ enum class Sdl2Application::Flag: UnsignedByte {
     #endif
 };
 
+Containers::StringView Sdl2Application::keyName(const Key key) {
+    return SDL_GetKeyName(SDL_Keycode(key));
+}
+
+#ifndef CORRADE_TARGET_EMSCRIPTEN
+Containers::StringView Sdl2Application::scanCodeName(const UnsignedInt scanCode) {
+    return SDL_GetScancodeName(SDL_Scancode(scanCode));
+}
+#endif
+
+/* https://github.com/emscripten-core/emscripten/pull/18060 */
+#if !defined(CORRADE_TARGET_EMSCRIPTEN) || __EMSCRIPTEN_major__*10000 + __EMSCRIPTEN_minor__*100 + __EMSCRIPTEN_tiny__ >= 30125
+Containers::Optional<UnsignedInt> Sdl2Application::keyToScanCode(const Key key) {
+    static_assert(SDL_SCANCODE_UNKNOWN == 0, "assumed SDL_SCANCODE_UNKNOWN to be 0");
+    if(const SDL_Scancode scanCode = SDL_GetScancodeFromKey(SDL_Keycode(key)))
+        return UnsignedInt(scanCode);
+    return {};
+}
+#endif
+
+#ifndef CORRADE_TARGET_EMSCRIPTEN
+Containers::Optional<Sdl2Application::Key> Sdl2Application::scanCodeToKey(const UnsignedInt scanCode) {
+    if(const SDL_Keycode key = SDL_GetKeyFromScancode(SDL_Scancode(scanCode)))
+        return Key(key);
+    return {};
+}
+#endif
+
 Sdl2Application::Sdl2Application(const Arguments& arguments): Sdl2Application{arguments, Configuration{}} {}
 
 Sdl2Application::Sdl2Application(const Arguments& arguments, const Configuration& configuration): Sdl2Application{arguments, NoCreate} {
@@ -1041,7 +1069,7 @@ bool Sdl2Application::mainLoopIteration() {
 
             case SDL_KEYDOWN:
             case SDL_KEYUP: {
-                KeyEvent e{event, Key(event.key.keysym.sym), fixedModifiers(event.key.keysym.mod), event.key.repeat != 0};
+                KeyEvent e{event, Key(event.key.keysym.sym), UnsignedInt(event.key.keysym.scancode), fixedModifiers(event.key.keysym.mod), event.key.repeat != 0};
                 event.type == SDL_KEYDOWN ? keyPressEvent(e) : keyReleaseEvent(e);
             } break;
 
@@ -1598,14 +1626,22 @@ Sdl2Application::Configuration::Configuration():
 
 Sdl2Application::Configuration::~Configuration() = default;
 
+#ifdef MAGNUM_BUILD_DEPRECATED
 Containers::StringView Sdl2Application::KeyEvent::keyName(const Sdl2Application::Key key) {
-    return SDL_GetKeyName(SDL_Keycode(key));
+    return Sdl2Application::keyName(key);
 }
+#endif
 
 Containers::StringView Sdl2Application::KeyEvent::keyName() const {
-    return keyName(_key);
+    return Sdl2Application::keyName(_key);
 }
 
+#ifndef CORRADE_TARGET_EMSCRIPTEN
+Containers::StringView Sdl2Application::KeyEvent::scanCodeName() const {
+    return Sdl2Application::scanCodeName(_scancode);
+}
+#endif
+
 Sdl2Application::Modifiers Sdl2Application::PointerEvent::modifiers() {
     if(!_modifiers)
         _modifiers = fixedModifiers(Uint16(SDL_GetModState()));

src/Magnum/Platform/Sdl2Application.h

@@ -86,6 +86,18 @@
 #include <Corrade/Containers/StringStl.h>
 #endif
 
+#if defined(CORRADE_TARGET_EMSCRIPTEN) || defined(DOXYGEN_GENERATING_OUTPUT)
+/* The __EMSCRIPTEN_major__ etc macros used to be passed implicitly, version
+   3.1.4 moved them to a version header and version 3.1.23 dropped the
+   backwards compatibility. To work consistently on all versions, including the
+   header only if the version macros aren't present.
+   https://github.com/emscripten-core/emscripten/commit/f99af02045357d3d8b12e63793cef36dfde4530a
+   https://github.com/emscripten-core/emscripten/commit/f76ddc702e4956aeedb658c49790cc352f892e4c */
+#ifndef __EMSCRIPTEN_major__
+#include <emscripten/version.h>
+#endif
+#endif
+
 #ifndef DOXYGEN_GENERATING_OUTPUT
 union SDL_Event; /* for anyEvent() */
 #endif
@@ -574,6 +586,71 @@ class Sdl2Application {
          */
         typedef Containers::EnumSet<Pointer> Pointers;
 
+        /**
+         * @brief Name for given key
+         * @m_since_latest
+         *
+         * Human-readable localized UTF-8 name for given @p key, intended for
+         * displaying to the user in e.g. a key binding configuration. If there
+         * is no name for given key, empty string is returned. The returned
+         * view is always @relativeref{Corrade,Containers::StringViewFlag::NullTerminated}
+         * and is valid at least until the next call to this function, to
+         * @ref KeyEvent::keyName() const or to the underlying
+         * @cpp SDL_GetKeyName() @ce API.
+         * @see @ref scanCodeName(), @ref keyToScanCode(), @ref KeyEvent::key()
+         */
+        static Containers::StringView keyName(Key key);
+
+        #ifndef CORRADE_TARGET_EMSCRIPTEN
+        /**
+         * @brief Name for given key scan code
+         * @m_since_latest
+         *
+         * Human-readable localized UTF-8 name for given @p scancode. Note that
+         * unlike @ref keyName(), the scancode names are not consistent across
+         * platforms. If there is no name for given scancode, empty string is
+         * returned. The returned view is always
+         * @relativeref{Corrade,Containers::StringViewFlag::NullTerminated} and
+         * is valid at least until the next call to this function, to
+         * @ref KeyEvent::scanCodeName() const or to the underlying
+         * @cpp SDL_GetScancodeName() @ce API.
+         * @note Not available on @ref CORRADE_TARGET_EMSCRIPTEN "Emscripten".
+         * @see @ref scanCodeToKey(), @ref KeyEvent::scanCode()
+         */
+        static Containers::StringView scanCodeName(UnsignedInt scanCode);
+        #endif
+
+        #if !defined(CORRADE_TARGET_EMSCRIPTEN) || __EMSCRIPTEN_major__*10000 + __EMSCRIPTEN_minor__*100 + __EMSCRIPTEN_tiny__ >= 30125
+        /**
+         * @brief Scan code for given key
+         * @m_since_latest
+         *
+         * If @p key doesn't correspond to a physical key supported on given
+         * platform, returns @relativeref{Corrade,Containers::NullOpt}. Note
+         * that this is implemented as a linear lookup inside SDL, prefer to
+         * query the scan code directly via @ref KeyEvent::scanCode() rather
+         * than converting it from a @ref KeyEvent::key() at a later time.
+         * @note On @ref CORRADE_TARGET_EMSCRIPTEN "Emscripten" available only
+         *      since version 3.1.25.
+         * @see @ref scanCodeToKey(), @ref keyName()
+         */
+        static Containers::Optional<UnsignedInt> keyToScanCode(Key key);
+        #endif
+
+        #ifndef CORRADE_TARGET_EMSCRIPTEN
+        /**
+         * @brief Scan code for given key
+         * @m_since_latest
+         *
+         * If @p scanCode isn't a known scan code, returns
+         * @relativeref{Corrade,Containers::NullOpt}.
+         * @note Not available on @ref CORRADE_TARGET_EMSCRIPTEN "Emscripten".
+         * @see @ref KeyEvent::key(), @ref KeyEvent::scanCode(),
+         *      @ref keyToScanCode(), @ref scanCodeName()
+         */
+        static Containers::Optional<Key> scanCodeToKey(UnsignedInt scanCode);
+        #endif
+
         #ifdef MAGNUM_TARGET_GL
         /**
          * @brief Construct with an OpenGL context
@@ -2769,41 +2846,68 @@ class Sdl2Application::KeyEvent: public Sdl2Application::InputEvent {
          * @m_deprecated_since_latest Use @ref Sdl2Application::Key instead.
          */
         typedef CORRADE_DEPRECATED("use Sdl2Application::Key instead") Sdl2Application::Key Key;
-        #endif
 
         /**
-         * @brief Name for given key
-         *
-         * Human-readable localized UTF-8 name for given @p key, intended for
-         * displaying to the user in e.g. key binding configuration. If there
-         * is no name for given key, empty string is returned. The returned
-         * view is always @relativeref{Corrade,Containers::StringViewFlag::NullTerminated}
-         * and is valid at least until the next call to this function, to
-         * @ref keyName() const or to the underlying @cpp SDL_GetKeyName() @ce
-         * API.
+         * @brief @copybrief Sdl2Application::keyName()
+         * @m_deprecated_since_latest Use @ref Sdl2Application::keyName()
+         *      instead.
          */
-        static Containers::StringView keyName(Sdl2Application::Key key);
+        CORRADE_DEPRECATED("use Sdl2Application::keyName() instead") static Containers::StringView keyName(Sdl2Application::Key key);
+        #endif
 
         /**
          * @brief Key
          *
-         * @see @ref keyName()
+         * Layout-dependent name of given key. Use @ref scanCode() to get a
+         * platform-specific but layout-independent identifier of given key.
+         * @see @ref keyName() const, @ref keyToScanCode()
          */
         Sdl2Application::Key key() const { return _key; }
 
+        /**
+         * @brief Scancode
+         * @m_since_latest
+         *
+         * Platform-specific but layout-independent identifier of given key.
+         * Use @ref key() to get a key name in the currently used layout.
+         * @see @ref scanCodeName(), @ref scanCodeToKey()
+         */
+        UnsignedInt scanCode() const { return _scancode; }
+
         /**
          * @brief Key name
          *
          * Human-readable localized UTF-8 name for the key returned by
-         * @ref key(), intended for displaying to the user in e.g.
-         * key binding configuration. If there is no name for that key, empty
-         * string is returned. The returned string is always @relativeref{Corrade,Containers::StringViewFlag::NullTerminated}
+         * @ref key(), intended for displaying to the user in e.g. a key
+         * binding configuration. If there is no name for that key, an empty
+         * string is returned. The returned string is always
+         * @relativeref{Corrade,Containers::StringViewFlag::NullTerminated}
          * and is valid at least until the next call to this function, to
-         * @ref keyName(Key) or to the underlying @cpp SDL_GetKeyName() @ce
-         * API.
+         * @ref Sdl2Application::keyName() or to the underlying
+         * @cpp SDL_GetKeyName() @ce API.
+         * @see @ref scanCodeName()
          */
         Containers::StringView keyName() const;
 
+        #ifndef CORRADE_TARGET_EMSCRIPTEN
+        /**
+         * @brief Scan code name
+         * @m_since_latest
+         *
+         * Human-readable localized UTF-8 name for the scancode returned by
+         * @ref scanCode(), intended for displaying to the user in e.g. a key
+         * binding configuration. If there is no name for that key, an
+         * empty string is returned. The returned string is always
+         * @relativeref{Corrade,Containers::StringViewFlag::NullTerminated}
+         * and is valid at least until the next call to this function, to
+         * @ref Sdl2Application::scanCodeName() or to the underlying
+         * @cpp SDL_GetScancodeName() @ce API.
+         * @note Not available on @ref CORRADE_TARGET_EMSCRIPTEN "Emscripten".
+         * @see @ref keyName()
+         */
+        Containers::StringView scanCodeName() const;
+        #endif
+
         /** @brief Modifiers */
         Sdl2Application::Modifiers modifiers() const { return _modifiers; }
 
@@ -2818,11 +2922,12 @@ class Sdl2Application::KeyEvent: public Sdl2Application::InputEvent {
     private:
         friend Sdl2Application;
 
-        explicit KeyEvent(const SDL_Event& event, Sdl2Application::Key key, Sdl2Application::Modifiers modifiers, bool repeated): InputEvent{event}, _key{key}, _modifiers{modifiers}, _repeated{repeated} {}
+        explicit KeyEvent(const SDL_Event& event, Sdl2Application::Key key, UnsignedInt scancode, Sdl2Application::Modifiers modifiers, bool repeated): InputEvent{event}, _repeated{repeated}, _modifiers{modifiers}, _key{key}, _scancode{scancode} {}
 
-        const Sdl2Application::Key _key;
-        const Sdl2Application::Modifiers _modifiers;
         const bool _repeated;
+        const Sdl2Application::Modifiers _modifiers;
+        const Sdl2Application::Key _key;
+        const UnsignedInt _scancode;
 };
 
 /**

src/Magnum/Platform/Test/EmscriptenApplicationTest.cpp

@@ -368,7 +368,7 @@ struct EmscriptenApplicationTest: Platform::Application {
 
     /* For testing keyboard capture */
     void keyPressEvent(KeyEvent& event) override {
-        Debug{} << "key press:" << event.key() << event.keyName() << event.modifiers();
+        Debug{} << "key press:" << event.key() << event.keyName() << "scancode:" << event.scanCodeName() << event.modifiers();
 
         if(event.key() == Key::F1) {
             Debug{} << "starting text input";
@@ -395,7 +395,7 @@ struct EmscriptenApplicationTest: Platform::Application {
     }
 
     void keyReleaseEvent(KeyEvent& event) override {
-        Debug{} << "key release:" << event.key() << event.keyName() << event.modifiers();
+        Debug{} << "key release:" << event.key() << event.keyName() << "scancode:" << event.scanCodeName() << event.modifiers();
 
         event.setAccepted();
     }

src/Magnum/Platform/Test/GlfwApplicationTest.cpp

@@ -299,7 +299,11 @@ struct GlfwApplicationTest: Platform::Application {
     }
 
     void keyPressEvent(KeyEvent& event) override {
-        Debug{} << "key press:" << event.key() << int(event.key()) << event.keyName() << event.modifiers();
+        Debug{} << "key press:" << event.key() << int(event.key()) << event.keyName() << "scancode:" << event.scanCode() << event.modifiers()
+            #if GLFW_VERSION_MAJOR*100 + GLFW_VERSION_MINOR >= 303
+            << "converted:" << keyToScanCode(event.key())
+            #endif
+            ;
 
         if(event.key() == Key::F1) {
             Debug{} << "starting text input";
@@ -337,7 +341,11 @@ struct GlfwApplicationTest: Platform::Application {
     }
 
     void keyReleaseEvent(KeyEvent& event) override {
-        Debug{} << "key release:" << event.key() << int(event.key()) << event.keyName() << event.modifiers();
+        Debug{} << "key release:" << event.key() << int(event.key()) << event.keyName() << "scancode:" << event.scanCode() << event.modifiers()
+            #if GLFW_VERSION_MAJOR*100 + GLFW_VERSION_MINOR >= 303
+            << "converted:" << keyToScanCode(event.key())
+            #endif
+            ;
     }
 
     /* Set to 0 to test the deprecated mouse events instead */

src/Magnum/Platform/Test/Sdl2ApplicationTest.cpp

@@ -56,8 +56,8 @@
 
 namespace Magnum { namespace Platform {
 
-/* These cannot be in an anonymous namespace as enumSetDebugOutput() below
-   wouldn't be able to pick them up */
+/* These cannot be in an anonymous namespace as enumSetDebugOutput() /
+   Optional<Key> below wouldn't be able to pick them up */
 
 static Debug& operator<<(Debug& debug, Application::Modifier value) {
     debug << "Modifier" << Debug::nospace;
@@ -77,118 +77,7 @@ static Debug& operator<<(Debug& debug, Application::Modifier value) {
     return debug << "(" << Debug::nospace << UnsignedInt(value) << Debug::nospace << ")";
 }
 
-static Debug& operator<<(Debug& debug, Application::Pointer value) {
-    debug << "Pointer" << Debug::nospace;
-
-    switch(value) {
-        #define _c(value) case Application::Pointer::value: return debug << "::" #value;
-        _c(MouseLeft)
-        _c(MouseMiddle)
-        _c(MouseRight)
-        _c(MouseButton4)
-        _c(MouseButton5)
-        #ifndef CORRADE_TARGET_EMSCRIPTEN
-        _c(Finger)
-        #endif
-        #undef _c
-    }
-
-    return debug << "(" << Debug::nospace << UnsignedInt(value) << Debug::nospace << ")";
-}
-
-#ifdef MAGNUM_BUILD_DEPRECATED
-CORRADE_IGNORE_DEPRECATED_PUSH
-CORRADE_UNUSED static Debug& operator<<(Debug& debug, Application::MouseMoveEvent::Button value) {
-    debug << "Button" << Debug::nospace;
-
-    switch(value) {
-        #define _c(value) case Application::MouseMoveEvent::Button::value: return debug << "::" #value;
-        _c(Left)
-        _c(Middle)
-        _c(Right)
-        _c(X1)
-        _c(X2)
-        #undef _c
-    }
-
-    return debug << "(" << Debug::nospace << UnsignedInt(value) << Debug::nospace << ")";
-}
-CORRADE_IGNORE_DEPRECATED_POP
-#endif
-
-namespace Test { namespace {
-
-static Debug& operator<<(Debug& debug, Application::PointerEventSource value) {
-    debug << "PointerEventSource" << Debug::nospace;
-
-    switch(value) {
-        #define _c(value) case Application::PointerEventSource::value: return debug << "::" #value;
-        _c(Mouse)
-        #ifndef CORRADE_TARGET_EMSCRIPTEN
-        _c(Touch)
-        #endif
-        #undef _c
-    }
-
-    return debug << "(" << Debug::nospace << UnsignedInt(value) << Debug::nospace << ")";
-}
-
-Debug& operator<<(Debug& debug, Application::Modifiers value) {
-    return Containers::enumSetDebugOutput(debug, value, "Modifiers{}", {
-        Application::Modifier::Shift,
-        Application::Modifier::Ctrl,
-        Application::Modifier::Alt,
-        Application::Modifier::Super,
-        Application::Modifier::AltGr,
-        Application::Modifier::CapsLock,
-        Application::Modifier::NumLock,
-    });
-}
-
-Debug& operator<<(Debug& debug, Application::Pointers value) {
-    return Containers::enumSetDebugOutput(debug, value, "Pointers{}", {
-        Application::Pointer::MouseLeft,
-        Application::Pointer::MouseMiddle,
-        Application::Pointer::MouseRight,
-        Application::Pointer::MouseButton4,
-        Application::Pointer::MouseButton5,
-        #ifndef CORRADE_TARGET_EMSCRIPTEN
-        Application::Pointer::Finger,
-        #endif
-    });
-}
-
-#ifdef MAGNUM_BUILD_DEPRECATED
-CORRADE_IGNORE_DEPRECATED_PUSH
-CORRADE_UNUSED Debug& operator<<(Debug& debug, Application::MouseEvent::Button value) {
-    debug << "Button" << Debug::nospace;
-
-    switch(value) {
-        #define _c(value) case Application::MouseEvent::Button::value: return debug << "::" #value;
-        _c(Left)
-        _c(Middle)
-        _c(Right)
-        _c(X1)
-        _c(X2)
-        #undef _c
-    }
-
-    return debug << "(" << Debug::nospace << UnsignedInt(value) << Debug::nospace << ")";
-}
-
-CORRADE_UNUSED Debug& operator<<(Debug& debug, Application::MouseMoveEvent::Buttons value) {
-    return Containers::enumSetDebugOutput(debug, value, "Buttons{}", {
-        Application::MouseMoveEvent::Button::Left,
-        Application::MouseMoveEvent::Button::Middle,
-        Application::MouseMoveEvent::Button::Right,
-        Application::MouseMoveEvent::Button::X1,
-        Application::MouseMoveEvent::Button::X2,
-    });
-}
-CORRADE_IGNORE_DEPRECATED_POP
-#endif
-
-Debug& operator<<(Debug& debug, Application::Key value) {
+static Debug& operator<<(Debug& debug, Application::Key value) {
     debug << "Key" << Debug::nospace;
 
     switch(value) {
@@ -308,6 +197,117 @@ Debug& operator<<(Debug& debug, Application::Key value) {
     return debug << "(" << Debug::nospace << UnsignedInt(value) << Debug::nospace << ")";
 }
 
+static Debug& operator<<(Debug& debug, Application::Pointer value) {
+    debug << "Pointer" << Debug::nospace;
+
+    switch(value) {
+        #define _c(value) case Application::Pointer::value: return debug << "::" #value;
+        _c(MouseLeft)
+        _c(MouseMiddle)
+        _c(MouseRight)
+        _c(MouseButton4)
+        _c(MouseButton5)
+        #ifndef CORRADE_TARGET_EMSCRIPTEN
+        _c(Finger)
+        #endif
+        #undef _c
+    }
+
+    return debug << "(" << Debug::nospace << UnsignedInt(value) << Debug::nospace << ")";
+}
+
+#ifdef MAGNUM_BUILD_DEPRECATED
+CORRADE_IGNORE_DEPRECATED_PUSH
+CORRADE_UNUSED static Debug& operator<<(Debug& debug, Application::MouseMoveEvent::Button value) {
+    debug << "Button" << Debug::nospace;
+
+    switch(value) {
+        #define _c(value) case Application::MouseMoveEvent::Button::value: return debug << "::" #value;
+        _c(Left)
+        _c(Middle)
+        _c(Right)
+        _c(X1)
+        _c(X2)
+        #undef _c
+    }
+
+    return debug << "(" << Debug::nospace << UnsignedInt(value) << Debug::nospace << ")";
+}
+CORRADE_IGNORE_DEPRECATED_POP
+#endif
+
+namespace Test { namespace {
+
+static Debug& operator<<(Debug& debug, Application::PointerEventSource value) {
+    debug << "PointerEventSource" << Debug::nospace;
+
+    switch(value) {
+        #define _c(value) case Application::PointerEventSource::value: return debug << "::" #value;
+        _c(Mouse)
+        #ifndef CORRADE_TARGET_EMSCRIPTEN
+        _c(Touch)
+        #endif
+        #undef _c
+    }
+
+    return debug << "(" << Debug::nospace << UnsignedInt(value) << Debug::nospace << ")";
+}
+
+Debug& operator<<(Debug& debug, Application::Modifiers value) {
+    return Containers::enumSetDebugOutput(debug, value, "Modifiers{}", {
+        Application::Modifier::Shift,
+        Application::Modifier::Ctrl,
+        Application::Modifier::Alt,
+        Application::Modifier::Super,
+        Application::Modifier::AltGr,
+        Application::Modifier::CapsLock,
+        Application::Modifier::NumLock,
+    });
+}
+
+Debug& operator<<(Debug& debug, Application::Pointers value) {
+    return Containers::enumSetDebugOutput(debug, value, "Pointers{}", {
+        Application::Pointer::MouseLeft,
+        Application::Pointer::MouseMiddle,
+        Application::Pointer::MouseRight,
+        Application::Pointer::MouseButton4,
+        Application::Pointer::MouseButton5,
+        #ifndef CORRADE_TARGET_EMSCRIPTEN
+        Application::Pointer::Finger,
+        #endif
+    });
+}
+
+#ifdef MAGNUM_BUILD_DEPRECATED
+CORRADE_IGNORE_DEPRECATED_PUSH
+CORRADE_UNUSED Debug& operator<<(Debug& debug, Application::MouseEvent::Button value) {
+    debug << "Button" << Debug::nospace;
+
+    switch(value) {
+        #define _c(value) case Application::MouseEvent::Button::value: return debug << "::" #value;
+        _c(Left)
+        _c(Middle)
+        _c(Right)
+        _c(X1)
+        _c(X2)
+        #undef _c
+    }
+
+    return debug << "(" << Debug::nospace << UnsignedInt(value) << Debug::nospace << ")";
+}
+
+CORRADE_UNUSED Debug& operator<<(Debug& debug, Application::MouseMoveEvent::Buttons value) {
+    return Containers::enumSetDebugOutput(debug, value, "Buttons{}", {
+        Application::MouseMoveEvent::Button::Left,
+        Application::MouseMoveEvent::Button::Middle,
+        Application::MouseMoveEvent::Button::Right,
+        Application::MouseMoveEvent::Button::X1,
+        Application::MouseMoveEvent::Button::X2,
+    });
+}
+CORRADE_IGNORE_DEPRECATED_POP
+#endif
+
 using namespace Containers::Literals;
 using namespace Math::Literals;
 
@@ -386,11 +386,19 @@ struct Sdl2ApplicationTest: Platform::Application {
     }
 
     void keyPressEvent(KeyEvent& event) override {
-        Debug{} << "key press:" << event.key() << "keycode:" << SDL_Keycode(event.key()) << event.keyName() << "scancode:" << event.event().key.keysym.scancode
+        Debug{} << "key press:" << event.key() << event.keyName() << "scancode:" << event.scanCode()
+            #ifndef CORRADE_TARGET_EMSCRIPTEN
+            << event.scanCodeName()
+            #endif
+            << event.modifiers()
+            #if !defined(CORRADE_TARGET_EMSCRIPTEN) || __EMSCRIPTEN_major__*10000 + __EMSCRIPTEN_minor__*100 + __EMSCRIPTEN_tiny__ >= 30125
+            << "converted:"
             #ifndef CORRADE_TARGET_EMSCRIPTEN
-            << SDL_GetScancodeName(event.event().key.keysym.scancode)
+            << scanCodeToKey(event.scanCode())
+            #endif
+            << keyToScanCode(event.key())
             #endif
-            << event.modifiers();
+            ;
 
         if(event.key() == Key::F1) {
             Debug{} << "starting text input";
@@ -451,11 +459,19 @@ struct Sdl2ApplicationTest: Platform::Application {
     }
 
     void keyReleaseEvent(KeyEvent& event) override {
-        Debug{} << "key release:" << event.key() << "keycode:" << SDL_Keycode(event.key()) << event.keyName() << "scancode:" << event.event().key.keysym.scancode
+        Debug{} << "key release:" << event.key() << event.keyName() << "scancode:" << event.scanCode()
             #ifndef CORRADE_TARGET_EMSCRIPTEN
-            << SDL_GetScancodeName(event.event().key.keysym.scancode)
+            << event.scanCodeName()
+            #endif
+            << event.modifiers()
+            #if !defined(CORRADE_TARGET_EMSCRIPTEN) || __EMSCRIPTEN_major__*10000 + __EMSCRIPTEN_minor__*100 + __EMSCRIPTEN_tiny__ >= 30125
+            << "converted:"
+            #ifndef CORRADE_TARGET_EMSCRIPTEN
+            << scanCodeToKey(event.scanCode())
+            #endif
+            << keyToScanCode(event.key())
             #endif
-            << event.modifiers();
+            ;
 
         /* With EmscriptenApplication, this makes the event stop from
            propagating further to the page (such as when pressing F1).