Platform: added *Application::KeyEvent::keyName().

The SDL2 variant works better than expected, however the GLFW variant
underdelivers -- no key names for modifier keys, the accent keys are not
UTF-8... I don't care ATM, will solve it once someone actually
complains.

src/Magnum/Platform/GlfwApplication.cpp

@@ -27,6 +27,7 @@
 #include "GlfwApplication.h"
 
 #include <tuple>
+#include <Corrade/Utility/String.h>
 
 #include "Magnum/Version.h"
 #include "Magnum/Platform/Context.h"
@@ -245,6 +246,15 @@ GlfwApplication::Configuration::Configuration():
 
 GlfwApplication::Configuration::~Configuration() = default;
 
+std::string GlfwApplication::KeyEvent::keyName(const Key key) {
+    /* It can return null, so beware */
+    return Utility::String::fromArray(glfwGetKeyName(int(key), 0));
+}
+
+std::string GlfwApplication::KeyEvent::keyName() const {
+    return keyName(_key);
+}
+
 template class BasicScreen<GlfwApplication>;
 template class BasicScreenedApplication<GlfwApplication>;
 

src/Magnum/Platform/GlfwApplication.h

@@ -744,9 +744,15 @@ class GlfwApplication::KeyEvent: public GlfwApplication::InputEvent {
             Menu = GLFW_KEY_MENU                /**< Menu */
         };
 
-        /** @brief Key */
+        /** @copydoc Sdl2Application::KeyEvent::keyName(Key) */
+        static std::string keyName(Key key);
+
+        /** @copydoc Sdl2Application::KeyEvent::key() */
         constexpr Key key() const { return _key; }
 
+        /** @copydoc Sdl2Application::KeyEvent::keyName() const */
+        std::string keyName() const;
+
         /** @brief Modifiers */
         constexpr Modifiers modifiers() const { return _modifiers; }
 

src/Magnum/Platform/Sdl2Application.cpp

@@ -552,6 +552,14 @@ Sdl2Application::Configuration::Configuration():
 
 Sdl2Application::Configuration::~Configuration() = default;
 
+std::string Sdl2Application::KeyEvent::keyName(const Key key) {
+    return SDL_GetKeyName(SDL_Keycode(key));
+}
+
+std::string Sdl2Application::KeyEvent::keyName() const {
+    return keyName(_key);
+}
+
 Sdl2Application::InputEvent::Modifiers Sdl2Application::MouseEvent::modifiers() {
     if(_modifiersLoaded) return _modifiers;
     _modifiersLoaded = true;

src/Magnum/Platform/Sdl2Application.h

@@ -1212,9 +1212,34 @@ class Sdl2Application::KeyEvent: public Sdl2Application::InputEvent {
             Z = SDLK_z                  /**< Letter Z */
         };
 
-        /** @brief Key */
+        /**
+         * @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.
+         * @see @ref keyName(Key)
+         */
+        static std::string keyName(Key key);
+
+        /**
+         * @brief Key
+         *
+         * @see @ref keyName()
+         */
         constexpr Key key() const { return _key; }
 
+        /**
+         * @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.
+         * @see @ref keyName(Key)
+         */
+        std::string keyName() const;
+
         /** @brief Modifiers */
         constexpr Modifiers modifiers() const { return _modifiers; }