magnum/src/Magnum/Platform/GlfwApplication.h

#ifndef Magnum_Platform_GlfwApplication_h
#define Magnum_Platform_GlfwApplication_h
/*
    This file is part of Magnum.

    Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019
              Vladimír Vondruš <mosra@centrum.cz>
    Copyright © 2016 Jonathan Hale <squareys@googlemail.com>
    Copyright © 2019, 2020 Marco Melorio <m.melorio@icloud.com>

    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
    to deal in the Software without restriction, including without limitation
    the rights to use, copy, modify, merge, publish, distribute, sublicense,
    and/or sell copies of the Software, and to permit persons to whom the
    Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included
    in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
    DEALINGS IN THE SOFTWARE.
*/

/** @file
 * @brief Class @ref Magnum::Platform::GlfwApplication, macro @ref MAGNUM_GLFWAPPLICATION_MAIN()
 */

#include <string>
#include <Corrade/Containers/ArrayView.h>
#include <Corrade/Containers/Optional.h>
#include <Corrade/Containers/Pointer.h>

#include "Magnum/Magnum.h"
#include "Magnum/Tags.h"
#include "Magnum/Math/Vector4.h"
#include "Magnum/Platform/Platform.h"

#ifdef MAGNUM_TARGET_GL
#include "Magnum/GL/GL.h"
#endif

#ifndef DOXYGEN_GENERATING_OUTPUT
#define GLFW_INCLUDE_NONE
#endif
#include <GLFW/glfw3.h>

namespace Magnum { namespace Platform {

namespace Implementation {
    enum class GlfwDpiScalingPolicy: UnsignedByte;
}

/** @nosubgrouping
@brief GLFW application

@m_keywords{Application}

Application using the [GLFW](http://glfw.org) toolkit. Supports keyboard and
mouse handling with support for changing cursor and mouse tracking and warping.
Available on all platforms where GLFW is ported.

@m_class{m-block m-success}

@thirdparty This library makes use of [GLFW](https://www.glfw.org/), released
    under the @m_class{m-label m-success} **zlib/libpng license**
    ([license text](https://www.glfw.org/license.html),
    [choosealicense.com](https://choosealicense.com/licenses/zlib/)).
    Attribution is appreciated but not required.

@section Platform-GlfwApplication-bootstrap Bootstrap application

Fully contained base application using @ref GlfwApplication along with CMake
setup is available in `base-glfw` branch of
[Magnum Bootstrap](https://github.com/mosra/magnum-bootstrap) repository,
download it as [tar.gz](https://github.com/mosra/magnum-bootstrap/archive/base-glfw.tar.gz)
or [zip](https://github.com/mosra/magnum-bootstrap/archive/base-glfw.zip) file.
After extracting the downloaded archive you can build and run the application
with these four commands:

@code{.sh}
mkdir build && cd build
cmake ..
cmake --build .
./src/MyApplication # or ./src/Debug/MyApplication
@endcode

See @ref cmake for more information.

@section Platform-GlfwApplication-usage General usage

This application library depends on the [GLFW](http://glfw.org) library and is
built if `WITH_GLFWAPPLICATION` is enabled when building Magnum. To use this
library with CMake, put
[FindGLFW.cmake](https://github.com/mosra/magnum/blob/master/modules/FindGLFW.cmake)
into your `modules/` directory, request the `GlfwApplication` component of the
`Magnum` package and link to the `Magnum::GlfwApplication` target:

@code{.cmake}
find_package(Magnum REQUIRED GlfwApplication)

# ...
target_link_libraries(your-app PRIVATE Magnum::GlfwApplication)
@endcode

Additionally, if you're using Magnum as a CMake subproject, bundle the
[glfw repository](https://github.com/glfw/glfw) and do the following
* *before* calling @cmake find_package() @ce to ensure it's enabled, as the
library is not built by default. If you want to use system-installed GLFW, omit
the first part and point `CMAKE_PREFIX_PATH` to its installation dir if
necessary.

@code{.cmake}
add_subdirectory(glfw)

set(WITH_GLFWAPPLICATION ON CACHE BOOL "" FORCE)
add_subdirectory(magnum EXCLUDE_FROM_ALL)
@endcode

If no other application is requested, you can also use the generic
`Magnum::Application` alias to simplify porting. Again, see @ref building and
@ref cmake for more information.

In C++ code you need to implement at least @ref drawEvent() to be able to draw
on the screen. The subclass can be then used directly in @cpp main() @ce
--- see convenience macro @ref MAGNUM_GLFWAPPLICATION_MAIN(). See @ref platform
for more information.

@code{.cpp}
class MyApplication: public Platform::GlfwApplication {
    // implement required methods...
};
MAGNUM_GLFWAPPLICATION_MAIN(MyApplication)
@endcode

If no other application header is included, this class is also aliased to
@cpp Platform::Application @ce and the macro is aliased to
@cpp MAGNUM_APPLICATION_MAIN() @ce to simplify porting.

@section Platform-GlfwApplication-dpi DPI awareness

DPI awareness behavior is consistent with @ref Sdl2Application except that iOS
or Emscripten specifics don't apply here. In addition, on Windows, GLFW is
implicitly advertising DPI awareness, so the manifest file described in
@ref platforms-windows-hidpi doesn't necessarily need to be supplied. See
@ref Platform-Sdl2Application-dpi "Sdl2Application DPI awareness documentation"
for more information.
*/
class GlfwApplication {
    public:
        /** @brief Application arguments */
        struct Arguments {
            /** @brief Constructor */
            /*implicit*/ constexpr Arguments(int& argc, char** argv) noexcept: argc{argc}, argv{argv} {}

            int& argc;      /**< @brief Argument count */
            char** argv;    /**< @brief Argument values */
        };

        class Configuration;
        #ifdef MAGNUM_TARGET_GL
        class GLConfiguration;
        #endif
        class ExitEvent;
        class ViewportEvent;
        class InputEvent;
        class KeyEvent;
        class MouseEvent;
        class MouseMoveEvent;
        class MouseScrollEvent;
        class TextInputEvent;

        #ifdef MAGNUM_TARGET_GL
        /**
         * @brief Construct with given configuration for OpenGL context
         * @param arguments         Application arguments
         * @param configuration     Application configuration
         * @param glConfiguration   OpenGL context configuration
         *
         * Creates application with default or user-specified configuration.
         * See @ref Configuration for more information. The program exits if
         * the context cannot be created, see @ref tryCreate() for an
         * alternative.
         *
         * @note This function is available only if Magnum is compiled with
         *      @ref MAGNUM_TARGET_GL enabled (done by default). See
         *      @ref building-features for more information.
         */
        explicit GlfwApplication(const Arguments& arguments, const Configuration& configuration, const GLConfiguration& glConfiguration);
        #endif

        /**
         * @brief Construct with given configuration
         *
         * If @ref Configuration::WindowFlag::Contextless is present or Magnum
         * was not built with @ref MAGNUM_TARGET_GL, this creates a window
         * without any GPU context attached, leaving that part on the user.
         *
         * If none of the flags is present and Magnum was built with
         * @ref MAGNUM_TARGET_GL, this is equivalent to calling
         * @ref GlfwApplication(const Arguments&, const Configuration&, const GLConfiguration&)
         * with default-constructed @ref GLConfiguration.
         *
         * See also @ref building-features for more information.
         */
        explicit GlfwApplication(const Arguments& arguments, const Configuration& configuration);

        /**
         * @brief Construct with default configuration
         *
         * Equivalent to calling @ref GlfwApplication(const Arguments&, const Configuration&)
         * with default-constructed @ref Configuration.
         */
        explicit GlfwApplication(const Arguments& arguments);

        /**
         * @brief Construct without creating a window
         * @param arguments     Application arguments
         *
         * Unlike above, the window is not created and must be created later
         * with @ref create() or @ref tryCreate().
         */
        explicit GlfwApplication(const Arguments& arguments, NoCreateT);

        /** @brief Copying is not allowed */
        GlfwApplication(const GlfwApplication&) = delete;

        /** @brief Moving is not allowed */
        GlfwApplication(GlfwApplication&&) = delete;

        /** @brief Copying is not allowed */
        GlfwApplication& operator=(const GlfwApplication&) = delete;

        /** @brief Moving is not allowed */
        GlfwApplication& operator=(GlfwApplication&&) = delete;

        /**
         * @brief Execute main loop
         * @return Value for returning from @cpp main() @ce
         *
         * Calls @ref mainLoopIteration() in a loop until @ref exit() is
         * called. See @ref MAGNUM_GLFWAPPLICATION_MAIN() for usage
         * information.
         */
        int exec();

        /**
         * @brief Run one iteration of application main loop
         * @return @cpp false @ce if @ref exit() was called and the application
         *      should exit, @cpp true @ce otherwise
         * @m_since_latest
         *
         * Called internally from @ref exec(). If you want to have better
         * control over how the main loop behaves, you can call this function
         * yourself from your own `main()` function instead of it being called
         * automatically from @ref exec() / @ref MAGNUM_GLFWAPPLICATION_MAIN().
         */
        bool mainLoopIteration();

        /**
         * @brief Exit application
         * @param exitCode  The exit code the application should return
         *
         * When called from application constructor, it will cause the
         * application to exit immediately after constructor ends, without any
         * events being processed (thus not even @ref exitEvent()). Calling
         * this function is recommended over @ref std::exit() or
         * @ref Corrade::Utility::Fatal "Fatal", which exit without calling
         * destructors on local scope. Note that, however, you need to
         * explicitly @cpp return @ce after calling it, as it can't exit the
         * constructor on its own:
         *
         * @snippet MagnumPlatform.cpp exit-from-constructor
         *
         * When called from the main loop, the application exits cleanly
         * before next main loop iteration is executed.
         */
        void exit(int exitCode = 0);

        /**
         * @brief Underlying window handle
         *
         * Use in case you need to call GLFW functionality directly.
         */
        GLFWwindow* window() { return _window; }

    protected:
        /* Nobody will need to have (and delete) GlfwApplication*, thus this is
           faster than public pure virtual destructor */
        ~GlfwApplication();

        #ifdef MAGNUM_TARGET_GL
        /**
         * @brief Create a window with given configuration for OpenGL context
         * @param configuration     Application configuration
         * @param glConfiguration   OpenGL context configuration
         *
         * Must be called only if the context wasn't created by the constructor
         * itself, i.e. when passing @ref NoCreate to it. Error message is
         * printed and the program exits if the context cannot be created, see
         * @ref tryCreate() for an alternative.
         *
         * On desktop GL, if version is not specified in @p glConfiguration,
         * the application first tries to create core context (OpenGL 3.2+) and
         * if that fails, falls back to compatibility OpenGL 2.1 context.
         *
         * @note This function is available only if Magnum is compiled with
         *      @ref MAGNUM_TARGET_GL enabled (done by default). See
         *      @ref building-features for more information.
         */
        void create(const Configuration& configuration, const GLConfiguration& glConfiguration);
        #endif

        /**
         * @brief Create a window with given configuration
         *
         * If @ref Configuration::WindowFlag::Contextless is present or Magnum
         * was not built with @ref MAGNUM_TARGET_GL, this creates a window
         * without any GPU context attached, leaving that part on the user.
         *
         * If none of the flags is present and Magnum was built with
         * @ref MAGNUM_TARGET_GL, this is equivalent to calling
         * @ref create(const Configuration&, const GLConfiguration&) with
         * default-constructed @ref GLConfiguration.
         *
         * See also @ref building-features for more information.
         */
        void create(const Configuration& configuration);

        /**
         * @brief Create a window with default configuration and OpenGL context
         *
         * Equivalent to calling @ref create(const Configuration&) with
         * default-constructed @ref Configuration.
         */
        void create();

        #ifdef MAGNUM_TARGET_GL
        /**
         * @brief Try to create context with given configuration for OpenGL context
         *
         * Unlike @ref create(const Configuration&, const GLConfiguration&)
         * returns @cpp false @ce if the context cannot be created,
         * @cpp true @ce otherwise.
         *
         * @note This function is available only if Magnum is compiled with
         *      @ref MAGNUM_TARGET_GL enabled (done by default). See
         *      @ref building-features for more information.
         */
        bool tryCreate(const Configuration& configuration, const GLConfiguration& glConfiguration);
        #endif

        /**
         * @brief Try to create context with given configuration
         *
         * Unlike @ref create(const Configuration&) returns @cpp false @ce if
         * the context cannot be created, @cpp true @ce otherwise.
         */
        bool tryCreate(const Configuration& configuration);

        /** @{ @name Screen handling */

    public:
        /**
         * @brief Window size
         *
         * Window size to which all input event coordinates can be related.
         * Note that, especially on HiDPI systems, it may be different from
         * @ref framebufferSize(). Expects that a window is already created.
         * See @ref Platform-GlfwApplication-dpi for more information.
         * @see @ref dpiScaling()
         */
        Vector2i windowSize() const;

        /**
         * @brief Set window size
         * @param size    The size, in screen coordinates
         * @m_since_latest
         *
         * To make the sizing work independently of the display DPI, @p size is
         * internally multiplied with @ref dpiScaling() before getting applied.
         * Expects that a window is already created.
         * @see @ref setMinWindowSize(), @ref setMaxWindowSize()
         */
        void setWindowSize(const Vector2i& size);

        #if GLFW_VERSION_MAJOR*100 + GLFW_VERSION_MINOR >= 302 || defined(DOXYGEN_GENERATING_OUTPUT)
        /**
         * @brief Set window minimum size
         * @param size    The minimum size, in screen coordinates
         * @m_since{2019,10}
         *
         * If a value is set to @cpp -1 @ce, it will disable/remove the
         * corresponding limit. To make the sizing work independently of the
         * display DPI, @p size is internally multiplied with @ref dpiScaling()
         * before getting applied. Expects that a window is already created.
         * @note Supported since GLFW 3.2.
         * @see @ref setMaxWindowSize(), @ref setWindowSize()
         */
        void setMinWindowSize(const Vector2i& size = {-1, -1});

        /**
         * @brief Set window maximum size
         * @param size    The maximum size, in screen coordinates
         * @m_since{2019,10}
         *
         * If a value is set to @cpp -1 @ce, it will disable/remove the
         * corresponding limit. To make the sizing work independently of the
         * display DPI, @p size is internally multiplied with @ref dpiScaling()
         * before getting applied. Expects that a window is already created.
         * @note Supported since GLFW 3.2.
         * @see @ref setMinWindowSize(), @ref setMaxWindowSize()
         */
        void setMaxWindowSize(const Vector2i& size = {-1, -1});
        #endif

        #if defined(MAGNUM_TARGET_GL) || defined(DOXYGEN_GENERATING_OUTPUT)
        /**
         * @brief Framebuffer size
         *
         * Size of the default framebuffer. Note that, especially on HiDPI
         * systems, it may be different from @ref windowSize(). Expects that a
         * window is already created. See @ref Platform-GlfwApplication-dpi for
         * more information.
         *
         * @note This function is available only if Magnum is compiled with
         *      @ref MAGNUM_TARGET_GL enabled (done by default). See
         *      @ref building-features for more information.
         *
         * @see @ref dpiScaling()
         */
        Vector2i framebufferSize() const;
        #endif

        /**
         * @brief DPI scaling
         *
         * How the content should be scaled relative to system defaults for
         * given @ref windowSize(). If a window is not created yet, returns
         * zero vector, use @ref dpiScaling(const Configuration&) for
         * calculating a value independently. See @ref Platform-GlfwApplication-dpi
         * for more information.
         * @see @ref framebufferSize()
         */
        Vector2 dpiScaling() const { return _dpiScaling; }

        /**
         * @brief DPI scaling for given configuration
         *
         * Calculates DPI scaling that would be used when creating a window
         * with given @p configuration. Takes into account DPI scaling policy
         * and custom scaling specified on the command-line. See
         * @ref Platform-GlfwApplication-dpi for more information.
         */
        Vector2 dpiScaling(const Configuration& configuration);

        /**
         * @brief Set window title
         * @m_since{2019,10}
         *
         * The @p title is expected to be encoded in UTF-8.
         */
        void setWindowTitle(const std::string& title);

        #if GLFW_VERSION_MAJOR*100 + GLFW_VERSION_MINOR >= 302 || defined(DOXYGEN_GENERATING_OUTPUT)
        /**
         * @brief Set window icon
         * @m_since_latest
         *
         * The @p images are expected to be with origin at bottom left (which
         * is the default for imported images) and in one of
         * @ref PixelFormat::RGB8Unorm, @ref PixelFormat::RGB8Srgb,
         * @ref PixelFormat::RGBA8Unorm or @ref PixelFormat::RGBA8Srgb formats.
         * If you have just one image, you can use
         * @ref setWindowIcon(const ImageView2D&) instead.
         * @note Available since GLFW 3.2. The function has no effect on macOS
         *      / Wayland, see @m_class{m-doc-external} [glfwSetWindowIcon()](https://www.glfw.org/docs/latest/group__window.html#gadd7ccd39fe7a7d1f0904666ae5932dc5)
         *      for more information.
         */
        void setWindowIcon(std::initializer_list<ImageView2D> images);

        /**
         * @overload
         * @m_since_latest
         */
        void setWindowIcon(const ImageView2D& image);
        #endif

        /**
         * @brief Swap buffers
         *
         * Paints currently rendered framebuffer on screen.
         */
        void swapBuffers() { glfwSwapBuffers(_window); }

        /**
         * @brief Set swap interval
         *
         * Set @cpp 0 @ce for no VSync, @cpp 1 @ce for enabled VSync. Some
         * platforms support @cpp -1 @ce for late swap tearing. Default is
         * driver-dependent.
         *
         * @note Unlike SDL2, GLFW doesn't provide any getter for the swap
         *      interval, so this class doesn't provide any equivalent to
         *      @ref Sdl2Application::swapInterval().
         */
        void setSwapInterval(Int interval);

        /** @copydoc Sdl2Application::redraw() */
        void redraw();

    private:
        /**
         * @brief Viewport event
         *
         * Called when window size changes. The default implementation does
         * nothing. If you want to respond to size changes, you should pass the
         * new size to @ref GL::DefaultFramebuffer::setViewport() (if using
         * OpenGL) and possibly elsewhere (to
         * @ref SceneGraph::Camera::setViewport(), other framebuffers...).
         *
         * Note that this function might not get called at all if the window
         * size doesn't change. You should configure the initial state of your
         * cameras, framebuffers etc. in application constructor rather than
         * relying on this function to be called. Size of the window can be
         * retrieved using @ref windowSize(), size of the backing framebuffer
         * via @ref framebufferSize() and DPI scaling using @ref dpiScaling().
         * See @ref Platform-GlfwApplication-dpi for detailed info about these
         * values.
         */
        virtual void viewportEvent(ViewportEvent& event);

        #ifdef MAGNUM_BUILD_DEPRECATED
        /** @brief @copybrief viewportEvent(ViewportEvent&)
         * @m_deprecated_since{2018,10} Use @ref viewportEvent(ViewportEvent&)
         *      instead. To preserve backwards compatibility, this function is
         *      called from @ref viewportEvent(ViewportEvent&) with
         *      @ref ViewportEvent::windowSize() passed to @p size. Overriding
         *      the new function will cause this function to not be called
         *      anymore.
         */
        virtual CORRADE_DEPRECATED("use viewportEvent(ViewportEvent&) instead") void viewportEvent(const Vector2i& size);
        #endif

        /** @copydoc Sdl2Application::drawEvent() */
        virtual void drawEvent() = 0;

        /* Since 1.8.17, the original short-hand group closing doesn't work
           anymore. FFS. */
        /**
         * @}
         */

        /** @{ @name Keyboard handling */

        /** @copydoc Sdl2Application::keyPressEvent() */
        virtual void keyPressEvent(KeyEvent& event);

        /** @copydoc Sdl2Application::keyReleaseEvent() */
        virtual void keyReleaseEvent(KeyEvent& event);

        /* Since 1.8.17, the original short-hand group closing doesn't work
           anymore. FFS. */
        /**
         * @}
         */

        /** @{ @name Mouse handling */

    public:
        /**
         * @brief Cursor type
         * @m_since_latest
         *
         * @see @ref setCursor()
         */
        enum class Cursor: UnsignedInt {
            Arrow,          /**< Arrow */
            TextInput,      /**< Text input */
            Crosshair,      /**< Crosshair */

            /* Checking for GLFW_RESIZE_NWSE_CURSOR being defined instead of a
               version check because older Git clones have version set to 3.4
               but don't contain those defines. All new cursors were added in
               the same commit, so it's okay to test for just one define. */
            #if defined(DOXYGEN_GENERATING_OUTPUT) || defined(GLFW_RESIZE_NWSE_CURSOR)
            /**
             * Double arrow pointing northwest and southeast
             * @note Available since GLFW 3.4.
             */
            ResizeNWSE,

            /**
             * Double arrow pointing northeast and southwest
             * @note Available since GLFW 3.4.
             */
            ResizeNESW,
            #endif

            ResizeWE,       /**< Double arrow pointing west and east */
            ResizeNS,       /**< Double arrow pointing north and south */

            #if defined(DOXYGEN_GENERATING_OUTPUT) || defined(GLFW_RESIZE_NWSE_CURSOR)
            /**
             * Four pointed arrow pointing north, south, east, and west
             * @note Available since GLFW 3.4.
             */
            ResizeAll,

            /**
             * Slashed circle or crossbones
             * @note Available since GLFW 3.4.
             */
            No,
            #endif

            Hand,           /**< Hand */
            Hidden,         /**< Hidden */
            HiddenLocked    /**< Hidden and locked */
        };

        /**
         * @brief Set cursor type
         * @m_since_latest
         *
         * Default is @ref Cursor::Arrow.
         */
        void setCursor(Cursor cursor);

        /**
         * @brief Get current cursor type
         * @m_since_latest
         */
        Cursor cursor();

        /**
         * @brief Warp mouse cursor to given coordinates
         * @m_since_latest
         */
        void warpCursor(const Vector2i& position) {
            glfwSetCursorPos(_window, Double(position.x()), Double(position.y()));
        }

    private:
        /** @copydoc Sdl2Application::mousePressEvent() */
        virtual void mousePressEvent(MouseEvent& event);

        /** @copydoc Sdl2Application::mouseReleaseEvent() */
        virtual void mouseReleaseEvent(MouseEvent& event);

        /**
         * @brief Mouse move event
         *
         * Called when any mouse button is pressed and mouse is moved. Default
         * implementation does nothing.
         */
        virtual void mouseMoveEvent(MouseMoveEvent& event);

        /** @copydoc Sdl2Application::mouseScrollEvent() */
        virtual void mouseScrollEvent(MouseScrollEvent& event);

        /* Since 1.8.17, the original short-hand group closing doesn't work
           anymore. FFS. */
        /**
         * @}
         */

        /** @{ @name Text input handling */
    public:
        /**
         * @brief Whether text input is active
         *
         * If text input is active, text input events go to
         * @ref textInputEvent().
         * @see @ref startTextInput(), @ref stopTextInput()
         */
        bool isTextInputActive() const;

        /**
         * @brief Start text input
         *
         * Starts text input that will go to @ref textInputEvent().
         * @see @ref stopTextInput(), @ref isTextInputActive()
         */
        void startTextInput();

        /**
         * @brief Stop text input
         *
         * Stops text input that went to @ref textInputEvent().
         * @see @ref startTextInput(), @ref isTextInputActive(),
         *      @ref textInputEvent()
         */
        void stopTextInput();

    private:
        /**
         * @brief Text input event
         *
         * Called when text input is active and the text is being input.
         * @see @ref isTextInputActive()
         */
        virtual void textInputEvent(TextInputEvent& event);

        /* Since 1.8.17, the original short-hand group closing doesn't work
           anymore. FFS. */
        /**
         * @}
         */

        /** @{ @name Special events */

        /**
         * @brief Exit event
         *
         * If implemented, it allows the application to react to an application
         * exit (for example to save its internal state) and suppress it as
         * well (for example to show a exit confirmation dialog). The default
         * implementation calls @ref ExitEvent::setAccepted() on @p event,
         * which tells the application that it's safe to exit.
         */
        virtual void exitEvent(ExitEvent& event);

        /* Since 1.8.17, the original short-hand group closing doesn't work
           anymore. FFS. */
        /**
         * @}
         */

    private:
        enum class Flag: UnsignedByte;
        typedef Containers::EnumSet<Flag> Flags;
        CORRADE_ENUMSET_FRIEND_OPERATORS(Flags)

        void setupCallbacks();

        GLFWcursor* _cursors[8]{};
        Cursor _cursor = Cursor::Arrow;

        /* These are saved from command-line arguments */
        bool _verboseLog{};
        Implementation::GlfwDpiScalingPolicy _commandLineDpiScalingPolicy{};
        Vector2 _commandLineDpiScaling;

        Vector2 _dpiScaling;
        GLFWwindow* _window{nullptr};
        Flags _flags;
        #ifdef MAGNUM_TARGET_GL
        Containers::Pointer<Platform::GLContext> _context;
        #endif
        int _exitCode = 0;

        Vector2i _minWindowSize, _maxWindowSize;
        Vector2i _previousMouseMovePosition{-1};
};

#ifdef MAGNUM_TARGET_GL
/**
@brief OpenGL context configuration

The created window is always with a double-buffered OpenGL context.

@note This function is available only if Magnum is compiled with
    @ref MAGNUM_TARGET_GL enabled (done by default). See @ref building-features
    for more information.

@see @ref GlfwApplication(), @ref create(), @ref tryCreate()
*/
class GlfwApplication::GLConfiguration {
    public:
        /**
         * @brief Context flag
         *
         * @see @ref Flags, @ref setFlags(), @ref GL::Context::Flag
         */
        enum class Flag: UnsignedByte {
            #ifndef MAGNUM_TARGET_GLES
            /**
             * Forward compatible context
             *
             * @requires_gl Core/compatibility profile distinction and forward
             *      compatibility applies only to desktop GL.
             */
            ForwardCompatible = 1 << 0,
            #endif

            #if defined(DOXYGEN_GENERATING_OUTPUT) || defined(GLFW_CONTEXT_NO_ERROR)
            /**
             * Specifies whether errors should be generated by the context.
             * If enabled, situations that would have generated errors instead
             * cause undefined behavior.
             *
             * @note Supported since GLFW 3.2.
             */
            NoError = 1 << 1,
            #endif

            /**
             * Debug context. Enabled automatically if the
             * `--magnum-gpu-validation` @ref GL-Context-command-line "command-line option"
             * is present.
             */
            Debug = 1 << 2,

            Stereo = 1 << 3     /**< Stereo rendering */
        };

        /**
         * @brief Context flags
         *
         * @see @ref setFlags(), @ref GL::Context::Flags
         */
        typedef Containers::EnumSet<Flag> Flags;

        explicit GLConfiguration();
        ~GLConfiguration();

        /** @brief Context flags */
        Flags flags() const { return _flags; }

        /**
         * @brief Set context flags
         * @return Reference to self (for method chaining)
         *
         * Default is @ref Flag::ForwardCompatible on desktop GL and no flags
         * on OpenGL ES.
         * @see @ref addFlags(), @ref clearFlags(), @ref GL::Context::flags()
         */
        GLConfiguration& setFlags(Flags flags) {
            _flags = flags;
            return *this;
        }

        /**
         * @brief Add context flags
         * @return Reference to self (for method chaining)
         *
         * Unlike @ref setFlags(), ORs the flags with existing instead of
         * replacing them. Useful for preserving the defaults.
         * @see @ref clearFlags()
         */
        GLConfiguration& addFlags(Flags flags) {
            _flags |= flags;
            return *this;
        }

        /**
         * @brief Clear context flags
         * @return Reference to self (for method chaining)
         *
         * Unlike @ref setFlags(), ANDs the inverse of @p flags with existing
         * instead of replacing them. Useful for removing default flags.
         * @see @ref addFlags()
         */
        GLConfiguration& clearFlags(Flags flags) {
            _flags &= ~flags;
            return *this;
        }

        /** @brief Context version */
        GL::Version version() const { return _version; }

        /**
         * @brief Set context version
         *
         * If requesting version greater or equal to OpenGL 3.2, core profile
         * is used. The created context will then have any version which is
         * backwards-compatible with requested one. Default is
         * @ref GL::Version::None, i.e. any provided version is used.
         */
        GLConfiguration& setVersion(GL::Version version) {
            _version = version;
            return *this;
        }

        /** @brief Color buffer size */
        Vector4i colorBufferSize() const { return _colorBufferSize; }

        /**
         * @brief Set color buffer size
         *
         * Default is @cpp {8, 8, 8, 8} @ce (8-bit-per-channel RGBA).
         * @see @ref setDepthBufferSize(), @ref setStencilBufferSize()
         */
        GLConfiguration& setColorBufferSize(const Vector4i& size) {
            _colorBufferSize = size;
            return *this;
        }

        /** @brief Depth buffer size */
        Int depthBufferSize() const { return _depthBufferSize; }

        /**
         * @brief Set depth buffer size
         *
         * Default is @cpp 24 @ce bits.
         * @see @ref setColorBufferSize(), @ref setStencilBufferSize()
         */
        GLConfiguration& setDepthBufferSize(Int size) {
            _depthBufferSize = size;
            return *this;
        }

        /** @brief Stencil buffer size */
        Int stencilBufferSize() const { return _stencilBufferSize; }

        /**
         * @brief Set stencil buffer size
         *
         * Default is @cpp 0 @ce bits (i.e., no stencil buffer).
         * @see @ref setColorBufferSize(), @ref setDepthBufferSize()
         */
        GLConfiguration& setStencilBufferSize(Int size) {
            _stencilBufferSize = size;
            return *this;
        }

        /** @brief Sample count */
        Int sampleCount() const { return _sampleCount; }

        /**
         * @brief Set sample count
         * @return Reference to self (for method chaining)
         *
         * Default is @cpp 0 @ce, thus no multisampling. The actual sample
         * count is ignored, GLFW either enables it or disables. See also
         * @ref GL::Renderer::Feature::Multisampling.
         */
        GLConfiguration& setSampleCount(Int count) {
            _sampleCount = count;
            return *this;
        }

        /** @brief sRGB-capable default framebuffer */
        bool isSrgbCapable() const { return _srgbCapable; }

        /**
         * @brief Set sRGB-capable default framebuffer
         *
         * Default is @cpp false @ce. See also
         * @ref GL::Renderer::Feature::FramebufferSrgb.
         * @return Reference to self (for method chaining)
         */
        GLConfiguration& setSrgbCapable(bool enabled) {
            _srgbCapable = enabled;
            return *this;
        }

        #ifdef MAGNUM_BUILD_DEPRECATED
        /**
         * @brief @copybrief isSrgbCapable()
         * @m_deprecated_since{2018,10} Use @ref isSrgbCapable() instead.
         */
        CORRADE_DEPRECATED("use isSrgbCapable() instead") bool isSRGBCapable() const { return isSrgbCapable(); }

        /**
         * @brief @copybrief setSrgbCapable()
         * @m_deprecated_since{2018,10} Use @ref setSrgbCapable() instead.
         */
        CORRADE_DEPRECATED("use setSrgbCapable() instead") GLConfiguration& setSRGBCapable(bool enabled) {
            return setSrgbCapable(enabled);
        }
        #endif

    private:
        Vector4i _colorBufferSize;
        Int _depthBufferSize, _stencilBufferSize;
        Int _sampleCount;
        GL::Version _version;
        Flags _flags;
        bool _srgbCapable;
};

CORRADE_ENUMSET_OPERATORS(GlfwApplication::GLConfiguration::Flags)
#endif

namespace Implementation {
    enum class GlfwDpiScalingPolicy: UnsignedByte {
        /* Using 0 for an "unset" value */

        #ifdef CORRADE_TARGET_APPLE
        Framebuffer = 1,
        #endif

        #ifndef CORRADE_TARGET_APPLE
        Virtual = 2,

        Physical = 3,
        #endif

        Default
            #ifdef CORRADE_TARGET_APPLE
            = Framebuffer
            #else
            = Virtual
            #endif
    };
}

/**
@brief Configuration

@see @ref GlfwApplication(), @ref create(), @ref tryCreate()
*/
class GlfwApplication::Configuration {
    public:
        /**
         * @brief Window flag
         *
         * @see @ref WindowFlags, @ref setWindowFlags()
         */
        enum class WindowFlag: UnsignedShort {
            Fullscreen = 1 << 0,   /**< Fullscreen window */
            Resizable = 1 << 1,    /**< Resizable window */
            Hidden = 1 << 2,       /**< Hidden window */

            #if defined(DOXYGEN_GENERATING_OUTPUT) || defined(GLFW_MAXIMIZED)
            /**
             * Maximized window
             *
             * @note Supported since GLFW 3.2.
             */
            Maximized = 1 << 3,
            #endif

            Minimized = 1 << 4,    /**< Minimized window */
            Floating = 1 << 5,     /**< Window floating above others, top-most */

            /**
             * Automatically iconify (minimize) if fullscreen window loses
             * input focus
             */
            AutoIconify = 1 << 6,

            Focused = 1 << 7,      /**< Window has input focus */

            #if defined(DOXYGEN_GENERATING_OUTPUT) || defined(GLFW_NO_API)
            /**
             * Do not create any GPU context. Use together with
             * @ref GlfwApplication(const Arguments&),
             * @ref GlfwApplication(const Arguments&, const Configuration&),
             * @ref create(const Configuration&) or
             * @ref tryCreate(const Configuration&) to prevent implicit
             * creation of an OpenGL context.
             *
             * @note Supported since GLFW 3.2.
             */
            Contextless = 1 << 8
            #endif
        };

        /**
         * @brief Window flags
         *
         * @see @ref setWindowFlags()
         */
        typedef Containers::EnumSet<WindowFlag> WindowFlags;

        /**
         * @brief DPI scaling policy
         *
         * DPI scaling policy when requesting a particular window size. Can
         * be overriden on command-line using `--magnum-dpi-scaling` or via
         * the `MAGNUM_DPI_SCALING` environment variable.
         * @see @ref setSize(), @ref Platform-Sdl2Application-dpi
         */
        #ifdef DOXYGEN_GENERATING_OUTPUT
        enum class DpiScalingPolicy: UnsignedByte {
            /**
             * Framebuffer DPI scaling. The window will have the same size as
             * requested, but the framebuffer size will be different. Supported
             * only on macOS and iOS and is also the only supported value
             * there.
             */
            Framebuffer,

            /**
             * Virtual DPI scaling. Scales the window based on UI scaling
             * setting in the system. Falls back to
             * @ref DpiScalingPolicy::Physical on platforms that don't support
             * it. Supported only on desktop platforms (except macOS) and it's
             * the default there.
             *
             * Equivalent to `--magnum-dpi-scaling virtual` passed on
             * command-line.
             */
            Virtual,

            /**
             * Physical DPI scaling. Takes the requested window size as a
             * physical size that a window would have on platform's default DPI
             * and scales it to have the same size on given display physical
             * DPI. On platforms that don't have a concept of a window it
             * causes the framebuffer to match screen pixels 1:1 without any
             * scaling. Supported on desktop platforms except macOS and on
             * mobile and web. Default on mobile and web.
             *
             * Equivalent to `--magnum-dpi-scaling physical` passed on
             * command-line.
             */
            Physical,

            /**
             * Default policy for current platform. Alias to one of
             * @ref DpiScalingPolicy::Framebuffer, @ref DpiScalingPolicy::Virtual
             * or @ref DpiScalingPolicy::Physical depending on platform. See
             * @ref Platform-Sdl2Application-dpi for details.
             */
            Default
        };
        #else
        typedef Implementation::GlfwDpiScalingPolicy DpiScalingPolicy;
        #endif

        #ifdef MAGNUM_BUILD_DEPRECATED
        /**
         * @brief Cursor mode
         *
         * @m_deprecated_since_latest Use @ref GlfwApplication::setCursor()
         *      instead.
         */
        enum class CORRADE_DEPRECATED_ENUM("use GlfwApplication::setCursor() instead") CursorMode: Int {
            /**
             * Visible unconstrained cursor
             *
             * @m_deprecated_since_latest Use @ref GlfwApplication::setCursor()
             *      with @ref Cursor::Arrow (or any other) instead.
             */
            Normal CORRADE_DEPRECATED_ENUM("use GlfwApplication::setCursor() with Cursor::Arrow instead") = GLFW_CURSOR_NORMAL,

            /**
             * Hidden cursor
             *
             * @m_deprecated_since_latest Use @ref GlfwApplication::setCursor()
             *      with @ref Cursor::Hidden instead.
             */
            Hidden CORRADE_DEPRECATED_ENUM("use GlfwApplication::setCursor() with Cursor::Hidden instead") = GLFW_CURSOR_HIDDEN,

            /**
             * Cursor hidden and locked window
             *
             * @m_deprecated_since_latest Use @ref GlfwApplication::setCursor()
             *      with @ref Cursor::HiddenLocked instead.
             */
            Disabled CORRADE_DEPRECATED_ENUM("use GlfwApplication::setCursor() with Cursor::HiddenLocked instead") = GLFW_CURSOR_DISABLED
        };
        #endif

        /*implicit*/ Configuration();
        ~Configuration();

        /** @brief Window title */
        std::string title() const { return _title; }

        /**
         * @brief Set window title
         * @return Reference to self (for method chaining)
         *
         * Default is @cpp "Magnum GLFW Application" @ce.
         */
        Configuration& setTitle(std::string title) {
            _title = std::move(title);
            return *this;
        }

        /** @brief Window size */
        Vector2i size() const { return _size; }

        /**
         * @brief DPI scaling policy
         *
         * If @ref dpiScaling() is non-zero, it has a priority over this value.
         * The `--magnum-dpi-scaling` command-line option has a priority over
         * any application-set value.
         * @see @ref setSize(const Vector2i&, DpiScalingPolicy)
         */
        DpiScalingPolicy dpiScalingPolicy() const { return _dpiScalingPolicy; }

        /**
         * @brief Custom DPI scaling
         *
         * If zero, then @ref dpiScalingPolicy() has a priority over this
         * value. The `--magnum-dpi-scaling` command-line option has a priority
         * over any application-set value.
         * @see @ref setSize(const Vector2i&, const Vector2&)
         * @todo change this on a DPI change event (GLFW 3.3 has a callback:
         *  https://github.com/mosra/magnum/issues/243#issuecomment-388384089)
         */
        Vector2 dpiScaling() const { return _dpiScaling; }

        /**
         * @brief Set window size
         * @param size              Desired window size
         * @param dpiScalingPolicy  Policy based on which DPI scaling will be set
         * @return Reference to self (for method chaining)
         *
         * Default is @cpp {800, 600} @ce. See @ref Platform-GlfwApplication-dpi
         * for more information.
         * @see @ref setSize(const Vector2i&, const Vector2&)
         */
        Configuration& setSize(const Vector2i& size, DpiScalingPolicy dpiScalingPolicy = DpiScalingPolicy::Default) {
            _size = size;
            _dpiScalingPolicy = dpiScalingPolicy;
            return *this;
        }

        /**
         * @brief Set window size with custom DPI scaling
         * @param size              Desired window size
         * @param dpiScaling        Custom DPI scaling value
         *
         * Compared to @ref setSize(const Vector2i&, DpiScalingPolicy) which
         * autodetects the DPI scaling value according to given policy, this
         * function sets the DPI scaling directly. The resulting
         * @ref GlfwApplication::windowSize() is @cpp size*dpiScaling @ce and
         * @ref GlfwApplication::dpiScaling() is @p dpiScaling.
         */
        Configuration& setSize(const Vector2i& size, const Vector2& dpiScaling) {
            _size = size;
            _dpiScaling = dpiScaling;
            return *this;
        }

        /** @brief Window flags */
        WindowFlags windowFlags() const {
            return _windowFlags;
        }

        /**
         * @brief Set window flags
         * @return  Reference to self (for method chaining)
         *
         * Default is @ref WindowFlag::Focused.
         */
        Configuration& setWindowFlags(WindowFlags windowFlags) {
            _windowFlags = windowFlags;
            return *this;
        }

        #ifdef MAGNUM_BUILD_DEPRECATED
        /**
         * @brief Cursor mode
         *
         * @m_deprecated_since_latest Use @ref GlfwApplication::cursor()
         *      instead.
         */
        CORRADE_IGNORE_DEPRECATED_PUSH
        CORRADE_DEPRECATED("use GlfwApplication::cursor() instead") CursorMode cursorMode() const {
            return _cursorMode;
        }
        CORRADE_IGNORE_DEPRECATED_POP

        /**
         * @brief Set cursor mode
         * @return  Reference to self (for method chaining)
         *
         * Default is @ref CursorMode::Normal.
         *
         * @m_deprecated_since_latest Use @ref GlfwApplication::setCursor()
         *      instead.
         */
        CORRADE_IGNORE_DEPRECATED_PUSH
        CORRADE_DEPRECATED("use GlfwApplication::setCursor() instead") Configuration& setCursorMode(CursorMode cursorMode) {
            _cursorMode = cursorMode;
            return *this;
        }
        CORRADE_IGNORE_DEPRECATED_POP
        #endif

    private:
        std::string _title;
        Vector2i _size;
        WindowFlags _windowFlags;
        DpiScalingPolicy _dpiScalingPolicy;
        Vector2 _dpiScaling;
        #ifdef MAGNUM_BUILD_DEPRECATED
        CORRADE_IGNORE_DEPRECATED_PUSH
        CursorMode _cursorMode = CursorMode::Normal;
        CORRADE_IGNORE_DEPRECATED_POP
        #endif
};

CORRADE_ENUMSET_OPERATORS(GlfwApplication::Configuration::WindowFlags)

/**
@brief Exit event

@see @ref exitEvent()
*/
class GlfwApplication::ExitEvent {
    public:
        /** @brief Copying is not allowed */
        ExitEvent(const ExitEvent&) = delete;

        /** @brief Moving is not allowed */
        ExitEvent(ExitEvent&&) = delete;

        /** @brief Copying is not allowed */
        ExitEvent& operator=(const ExitEvent&) = delete;

        /** @brief Moving is not allowed */
        ExitEvent& operator=(ExitEvent&&) = delete;

        /** @brief Whether the event is accepted */
        bool isAccepted() const { return _accepted; }

        /**
         * @brief Set event as accepted
         *
         * If the event is ignored (i.e., not set as accepted) in
         * @ref exitEvent(), the application won't exit. Default implementation
         * of @ref exitEvent() accepts the event.
         */
        void setAccepted(bool accepted = true) { _accepted = accepted; }

    private:
        friend GlfwApplication;

        explicit ExitEvent(): _accepted(false) {}

        bool _accepted;
};

/**
@brief Viewport event

@see @ref viewportEvent()
*/
class GlfwApplication::ViewportEvent {
    public:
        /** @brief Copying is not allowed */
        ViewportEvent(const ViewportEvent&) = delete;

        /** @brief Moving is not allowed */
        ViewportEvent(ViewportEvent&&) = delete;

        /** @brief Copying is not allowed */
        ViewportEvent& operator=(const ViewportEvent&) = delete;

        /** @brief Moving is not allowed */
        ViewportEvent& operator=(ViewportEvent&&) = delete;

        /**
         * @brief Window size
         *
         * On some platforms with HiDPI displays, window size can be different
         * from @ref framebufferSize(). See @ref Platform-GlfwApplication-dpi
         * for more information.
         * @see @ref GlfwApplication::windowSize()
         */
        Vector2i windowSize() const { return _windowSize; }

        #if defined(MAGNUM_TARGET_GL) || defined(DOXYGEN_GENERATING_OUTPUT)
        /**
         * @brief Framebuffer size
         *
         * On some platforms with HiDPI displays, framebuffer size can be
         * different from @ref windowSize(). See
         * @ref Platform-GlfwApplication-dpi for more information.
         *
         * @note This function is available only if Magnum is compiled with
         *      @ref MAGNUM_TARGET_GL enabled (done by default). See
         *      @ref building-features for more information.
         *
         * @see @ref GlfwApplication::framebufferSize(), @ref dpiScaling()
         */
        Vector2i framebufferSize() const { return _framebufferSize; }
        #endif

        /**
         * @brief DPI scaling
         *
         * On some platforms moving an app between displays can result in DPI
         * scaling value being changed in tandem with a window/framebuffer
         * size. Simply resizing a window doesn't change the DPI scaling value.
         * See @ref Platform-GlfwApplication-dpi for more information.
         * @see @ref GlfwApplication::dpiScaling(), @ref framebufferSize()
         */
        Vector2 dpiScaling() const { return _dpiScaling; }

    private:
        friend GlfwApplication;

        explicit ViewportEvent(const Vector2i& windowSize,
            #ifdef MAGNUM_TARGET_GL
            const Vector2i& framebufferSize,
            #endif
            const Vector2& dpiScaling): _windowSize{windowSize},
                #ifdef MAGNUM_TARGET_GL
                _framebufferSize{framebufferSize},
                #endif
                _dpiScaling{dpiScaling} {}

        const Vector2i _windowSize;
        #ifdef MAGNUM_TARGET_GL
        const Vector2i _framebufferSize;
        #endif
        const Vector2 _dpiScaling;
};

/**
@brief Base for input events

@see @ref KeyEvent, @ref MouseEvent, @ref MouseMoveEvent, @ref keyPressEvent(),
    @ref mousePressEvent(), @ref mouseReleaseEvent(), @ref mouseMoveEvent()
*/
class GlfwApplication::InputEvent {
    public:
        /**
         * @brief Modifier
         *
         * @see @ref Modifiers, @ref KeyEvent::modifiers(),
         *      @ref MouseEvent::modifiers()
         */
        enum class Modifier: Int {
            /**
             * Shift
             *
             * @see @ref KeyEvent::Key::LeftShift, @ref KeyEvent::Key::RightShift
             */
            Shift = GLFW_MOD_SHIFT,

            /**
             * Ctrl
             *
             * @see @ref KeyEvent::Key::LeftCtrl, @ref KeyEvent::Key::RightCtrl
             */
            Ctrl = GLFW_MOD_CONTROL,

            /**
             * Alt
             *
             * @see @ref KeyEvent::Key::LeftAlt, @ref KeyEvent::Key::RightAlt
             */
            Alt = GLFW_MOD_ALT,

            /**
             * Super key (Windows/⌘)
             *
             * @see @ref KeyEvent::Key::LeftSuper, @ref KeyEvent::Key::RightSuper
             */
            Super = GLFW_MOD_SUPER
        };

        /**
         * @brief Set of modifiers
         *
         * @see @ref KeyEvent::modifiers(), @ref MouseEvent::modifiers(),
         *      @ref MouseMoveEvent::modifiers()
         */
        typedef Containers::EnumSet<Modifier> Modifiers;

        /** @brief Copying is not allowed */
        InputEvent(const InputEvent&) = delete;

        /** @brief Moving is not allowed */
        InputEvent(InputEvent&&) = delete;

        /** @brief Copying is not allowed */
        InputEvent& operator=(const InputEvent&) = delete;

        /** @brief Moving is not allowed */
        InputEvent& operator=(InputEvent&&) = delete;

        /** @copydoc Sdl2Application::InputEvent::setAccepted() */
        void setAccepted(bool accepted = true) { _accepted = accepted; }

        /** @copydoc Sdl2Application::InputEvent::isAccepted() */
        bool isAccepted() const { return _accepted; }

    protected:
        explicit InputEvent(): _accepted(false) {}

        ~InputEvent() = default;

    private:
        bool _accepted;
};

CORRADE_ENUMSET_OPERATORS(GlfwApplication::InputEvent::Modifiers)

/**
@brief Key event

@see @ref keyPressEvent(), @ref keyReleaseEvent()
*/
class GlfwApplication::KeyEvent: public GlfwApplication::InputEvent {
    public:
        /**
         * @brief Key
         *
         * @see @ref key()
         */
        enum class Key: Int {
            Unknown = GLFW_KEY_UNKNOWN,         /**< Unknown key */

            /**
             * Left Shift
             *
             * @see @ref InputEvent::Modifier::Shift
             */
            LeftShift = GLFW_KEY_LEFT_SHIFT,

            /**
             * Right Shift
             *
             * @see @ref InputEvent::Modifier::Shift
             */
            RightShift = GLFW_KEY_RIGHT_SHIFT,

            /**
             * Left Ctrl
             *
             * @see @ref InputEvent::Modifier::Ctrl
             */
            LeftCtrl = GLFW_KEY_LEFT_CONTROL,

            /**
             * Right Ctrl
             *
             * @see @ref InputEvent::Modifier::Ctrl
             */
            RightCtrl = GLFW_KEY_RIGHT_CONTROL,

            /**
             * Left Alt
             *
             * @see @ref InputEvent::Modifier::Alt
             */
            LeftAlt = GLFW_KEY_LEFT_ALT,

            /**
             * Right Alt
             *
             * @see @ref InputEvent::Modifier::Alt
             */
            RightAlt = GLFW_KEY_RIGHT_ALT,

            /**
             * Left Super key (Windows/⌘)
             *
             * @see @ref InputEvent::Modifier::Super
             */
            LeftSuper = GLFW_KEY_LEFT_SUPER,

            /**
             * Right Super key (Windows/⌘)
             *
             * @see @ref InputEvent::Modifier::Super
             */
            RightSuper = GLFW_KEY_RIGHT_SUPER,

            /* no equivalent for Sdl2Application's AltGr */

            Enter = GLFW_KEY_ENTER,             /**< Enter */
            Esc = GLFW_KEY_ESCAPE,              /**< Escape */

            Up = GLFW_KEY_UP,                   /**< Up arrow */
            Down = GLFW_KEY_DOWN,               /**< Down arrow */
            Left = GLFW_KEY_LEFT,               /**< Left arrow */
            Right = GLFW_KEY_RIGHT,             /**< Right arrow */
            Home = GLFW_KEY_HOME,               /**< Home */
            End = GLFW_KEY_END,                 /**< End */
            PageUp = GLFW_KEY_PAGE_UP,          /**< Page up */
            PageDown = GLFW_KEY_PAGE_DOWN,      /**< Page down */
            Backspace = GLFW_KEY_BACKSPACE,     /**< Backspace */
            Insert = GLFW_KEY_INSERT,           /**< Insert */
            Delete = GLFW_KEY_DELETE,           /**< Delete */

            F1 = GLFW_KEY_F1,                   /**< F1 */
            F2 = GLFW_KEY_F2,                   /**< F2 */
            F3 = GLFW_KEY_F3,                   /**< F3 */
            F4 = GLFW_KEY_F4,                   /**< F4 */
            F5 = GLFW_KEY_F5,                   /**< F5 */
            F6 = GLFW_KEY_F6,                   /**< F6 */
            F7 = GLFW_KEY_F7,                   /**< F7 */
            F8 = GLFW_KEY_F8,                   /**< F8 */
            F9 = GLFW_KEY_F9,                   /**< F9 */
            F10 = GLFW_KEY_F10,                 /**< F10 */
            F11 = GLFW_KEY_F11,                 /**< F11 */
            F12 = GLFW_KEY_F12,                 /**< F12 */

            Space = GLFW_KEY_SPACE,             /**< Space */
            Tab = GLFW_KEY_TAB,                 /**< Tab */

            /**
             * Quote (<tt>'</tt>)
             * @m_since_latest
             */
            Quote = GLFW_KEY_APOSTROPHE,

            Comma = GLFW_KEY_COMMA,             /**< Comma */
            Period = GLFW_KEY_PERIOD,           /**< Period */
            Minus = GLFW_KEY_MINUS,             /**< Minus */
            /* Note: This may only be represented as SHIFT + = */
            Plus = '+',                         /**< Plus */
            Slash = GLFW_KEY_SLASH,             /**< Slash */
            /* Note: This may only be represented as SHIFT + 5 */
            Percent = '%',                      /**< Percent */
            Semicolon = GLFW_KEY_SEMICOLON,     /**< Semicolon (`;`) */

            #ifdef MAGNUM_BUILD_DEPRECATED
            /** Semicolon (`;`)
             * @m_deprecated_since{2019,01} Use @ref Key::Semicolon instead.
             */
            Smicolon CORRADE_DEPRECATED_ENUM("use Key::Semicolon instead") = Semicolon,
            #endif

            Equal = GLFW_KEY_EQUAL,             /**< Equal */

            /**
             * Left bracket (`[`)
             * @m_since_latest
             */
            LeftBracket = GLFW_KEY_LEFT_BRACKET,

            /**
             * Right bracket (`]`)
             * @m_since_latest
             */
            RightBracket = GLFW_KEY_RIGHT_BRACKET,

            /**
             * Backslash (`\`)
             * @m_since_latest
             */
            Backslash = GLFW_KEY_BACKSLASH,

            /**
             * Backquote (<tt>`</tt>)
             * @m_since_latest
             */
            Backquote = GLFW_KEY_GRAVE_ACCENT,

            /**
             * Non-US \#1
             * @m_since_latest
             */
            World1 = GLFW_KEY_WORLD_1,

            /**
             * Non-US \#2
             * @m_since_latest
             */
            World2 = GLFW_KEY_WORLD_2,

            Zero = GLFW_KEY_0,                  /**< Zero */
            One = GLFW_KEY_1,                   /**< One */
            Two = GLFW_KEY_2,                   /**< Two */
            Three = GLFW_KEY_3,                 /**< Three */
            Four = GLFW_KEY_4,                  /**< Four */
            Five = GLFW_KEY_5,                  /**< Five */
            Six = GLFW_KEY_6,                   /**< Six */
            Seven = GLFW_KEY_7,                 /**< Seven */
            Eight = GLFW_KEY_8,                 /**< Eight */
            Nine = GLFW_KEY_9,                  /**< Nine */

            A = GLFW_KEY_A,                     /**< Letter A */
            B = GLFW_KEY_B,                     /**< Letter B */
            C = GLFW_KEY_C,                     /**< Letter C */
            D = GLFW_KEY_D,                     /**< Letter D */
            E = GLFW_KEY_E,                     /**< Letter E */
            F = GLFW_KEY_F,                     /**< Letter F */
            G = GLFW_KEY_G,                     /**< Letter G */
            H = GLFW_KEY_H,                     /**< Letter H */
            I = GLFW_KEY_I,                     /**< Letter I */
            J = GLFW_KEY_J,                     /**< Letter J */
            K = GLFW_KEY_K,                     /**< Letter K */
            L = GLFW_KEY_L,                     /**< Letter L */
            M = GLFW_KEY_M,                     /**< Letter M */
            N = GLFW_KEY_N,                     /**< Letter N */
            O = GLFW_KEY_O,                     /**< Letter O */
            P = GLFW_KEY_P,                     /**< Letter P */
            Q = GLFW_KEY_Q,                     /**< Letter Q */
            R = GLFW_KEY_R,                     /**< Letter R */
            S = GLFW_KEY_S,                     /**< Letter S */
            T = GLFW_KEY_T,                     /**< Letter T */
            U = GLFW_KEY_U,                     /**< Letter U */
            V = GLFW_KEY_V,                     /**< Letter V */
            W = GLFW_KEY_W,                     /**< Letter W */
            X = GLFW_KEY_X,                     /**< Letter X */
            Y = GLFW_KEY_Y,                     /**< Letter Y */
            Z = GLFW_KEY_Z,                     /**< Letter Z */

            CapsLock = GLFW_KEY_CAPS_LOCK,      /**< Caps lock */
            ScrollLock = GLFW_KEY_SCROLL_LOCK,  /**< Scroll lock */
            NumLock = GLFW_KEY_NUM_LOCK,        /**< Num lock */
            PrintScreen = GLFW_KEY_PRINT_SCREEN,/**< Print screen */
            Pause = GLFW_KEY_PAUSE,             /**< Pause */
            Menu = GLFW_KEY_MENU,               /**< Menu */

            NumZero = GLFW_KEY_KP_0,            /**< Numpad zero */
            NumOne = GLFW_KEY_KP_1,             /**< Numpad one */
            NumTwo = GLFW_KEY_KP_2,             /**< Numpad two */
            NumThree = GLFW_KEY_KP_3,           /**< Numpad three */
            NumFour = GLFW_KEY_KP_4,            /**< Numpad four */
            NumFive = GLFW_KEY_KP_5,            /**< Numpad five */
            NumSix = GLFW_KEY_KP_6,             /**< Numpad six */
            NumSeven = GLFW_KEY_KP_7,           /**< Numpad seven */
            NumEight = GLFW_KEY_KP_8,           /**< Numpad eight */
            NumNine = GLFW_KEY_KP_9,            /**< Numpad nine */
            NumDecimal = GLFW_KEY_KP_DECIMAL,   /**< Numpad decimal */
            NumDivide = GLFW_KEY_KP_DIVIDE,     /**< Numpad divide */
            NumMultiply = GLFW_KEY_KP_MULTIPLY, /**< Numpad multiply */
            NumSubtract = GLFW_KEY_KP_SUBTRACT, /**< Numpad subtract */
            NumAdd = GLFW_KEY_KP_ADD,           /**< Numpad add */
            NumEnter = GLFW_KEY_KP_ENTER,       /**< Numpad enter */
            NumEqual = GLFW_KEY_KP_EQUAL        /**< Numpad equal */
        };

        #if defined(DOXYGEN_GENERATING_OUTPUT) || GLFW_VERSION_MAJOR*100 + GLFW_VERSION_MINOR >= 302
        /**
         * @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)
         * @note Supported since GLFW 3.2.
         */
        static std::string keyName(Key key);
        #endif

        /** @copydoc Sdl2Application::KeyEvent::key() */
        Key key() const { return _key; }

        #if defined(DOXYGEN_GENERATING_OUTPUT) || GLFW_VERSION_MAJOR*100 + GLFW_VERSION_MINOR >= 302
        /**
         * @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)
         * @note Supported since GLFW 3.2.
         */
        std::string keyName() const;
        #endif

        /** @brief Modifiers */
        Modifiers modifiers() const { return _modifiers; }

        /** @copydoc Sdl2Application::KeyEvent::isRepeated() */
        bool isRepeated() const { return _repeated; }

    private:
        friend GlfwApplication;

        explicit KeyEvent(Key key, Modifiers modifiers, bool repeated): _key{key}, _modifiers{modifiers}, _repeated{repeated} {}

        const Key _key;
        const Modifiers _modifiers;
        const bool _repeated;
};

/**
@brief Mouse event

@see @ref MouseMoveEvent, @ref MouseScrollEvent, @ref mousePressEvent(),
    @ref mouseReleaseEvent()
*/
class GlfwApplication::MouseEvent: public GlfwApplication::InputEvent {
    public:
        /**
         * @brief Mouse button
         *
         * @see @ref button()
         */
        enum class Button: int {
            Left = GLFW_MOUSE_BUTTON_LEFT,        /**< Left button */
            Middle = GLFW_MOUSE_BUTTON_MIDDLE,    /**< Middle button */
            Right = GLFW_MOUSE_BUTTON_RIGHT,      /**< Right button */
            Button1 = GLFW_MOUSE_BUTTON_1,        /**< Mouse button 1 */
            Button2 = GLFW_MOUSE_BUTTON_2,        /**< Mouse button 2 */
            Button3 = GLFW_MOUSE_BUTTON_3,        /**< Mouse button 3 */
            Button4 = GLFW_MOUSE_BUTTON_4,        /**< Mouse button 4 */
            Button5 = GLFW_MOUSE_BUTTON_5,        /**< Mouse button 5 */
            Button6 = GLFW_MOUSE_BUTTON_6,        /**< Mouse button 6 */
            Button7 = GLFW_MOUSE_BUTTON_7,        /**< Mouse button 7 */
            Button8 = GLFW_MOUSE_BUTTON_8,        /**< Mouse button 8 */
        };

        /** @brief Button */
        Button button() const { return _button; }

        /** @brief Position */
        Vector2i position() const { return _position; }

        /** @brief Modifiers */
        Modifiers modifiers() const { return _modifiers; }

    private:
        friend GlfwApplication;

        explicit MouseEvent(Button button, const Vector2i& position, Modifiers modifiers): _button{button}, _position{position}, _modifiers{modifiers} {}

        const Button _button;
        const Vector2i _position;
        const Modifiers _modifiers;
};

/**
@brief Mouse move event

@see @ref MouseEvent, @ref MouseScrollEvent, @ref mouseMoveEvent()
*/
class GlfwApplication::MouseMoveEvent: public GlfwApplication::InputEvent {
    public:
        /**
         * @brief Mouse button
         *
         * @see @ref Buttons, @ref buttons()
         */
        enum class Button: UnsignedInt {
            Left = 1 << GLFW_MOUSE_BUTTON_LEFT,     /**< Left button */
            Middle = 1 << GLFW_MOUSE_BUTTON_MIDDLE, /**< Middle button */
            Right = 1 << GLFW_MOUSE_BUTTON_RIGHT    /**< Right button */
        };

        /**
         * @brief Set of mouse buttons
         *
         * @see @ref buttons()
         */
        typedef Containers::EnumSet<Button> Buttons;

        /**
         * @brief Mouse buttons
         *
         * Lazily populated on first request.
         */
        Buttons buttons();

        /** @brief Position */
        Vector2i position() const { return _position; }

        /**
         * @brief Relative position
         * @m_since{2019,10}
         *
         * Position relative to previous move event. Unlike
         * @ref Sdl2Application, GLFW doesn't provide relative position
         * directly, so this is calculated explicitly as a delta from previous
         * move event position.
         */
        Vector2i relativePosition() const { return _relativePosition; }

        /**
         * @brief Modifiers
         *
         * Lazily populated on first request.
         */
        Modifiers modifiers();

    private:
        friend GlfwApplication;

        explicit MouseMoveEvent(GLFWwindow* window, const Vector2i& position, const Vector2i& relativePosition): _window{window}, _position{position}, _relativePosition{relativePosition} {}

        GLFWwindow* const _window;
        const Vector2i _position, _relativePosition;
        Containers::Optional<Buttons> _buttons;
        Containers::Optional<Modifiers> _modifiers;
};

CORRADE_ENUMSET_OPERATORS(GlfwApplication::MouseMoveEvent::Buttons)

/**
@brief Mouse scroll event

@see @ref MouseEvent, @ref MouseMoveEvent, @ref mouseScrollEvent()
*/
class GlfwApplication::MouseScrollEvent: public GlfwApplication::InputEvent {
    public:
        /** @brief Scroll offset */
        Vector2 offset() const { return _offset; }

        /**
         * @brief Position
         *
         * Lazily populated on first request.
         */
        Vector2i position();

        /**
         * @brief Modifiers
         *
         * Lazily populated on first request.
         */
        Modifiers modifiers();

    private:
        friend GlfwApplication;

        explicit MouseScrollEvent(GLFWwindow* window, const Vector2& offset): _window{window}, _offset{offset} {}

        GLFWwindow* const _window;
        const Vector2 _offset;
        Containers::Optional<Vector2i> _position;
        Containers::Optional<Modifiers> _modifiers;
};

/**
@brief Text input event

@see @ref textInputEvent()
*/
class GlfwApplication::TextInputEvent {
    public:
        /** @brief Copying is not allowed */
        TextInputEvent(const TextInputEvent&) = delete;

        /** @brief Moving is not allowed */
        TextInputEvent(TextInputEvent&&) = delete;

        /** @brief Copying is not allowed */
        TextInputEvent& operator=(const TextInputEvent&) = delete;

        /** @brief Moving is not allowed */
        TextInputEvent& operator=(TextInputEvent&&) = delete;

        /** @brief Whether the event is accepted */
        bool isAccepted() const { return _accepted; }

        /**
         * @brief Set event as accepted
         *
         * If the event is ignored (i.e., not set as accepted), it might be
         * propagated elsewhere, for example to another screen when using
         * @ref BasicScreenedApplication "ScreenedApplication". By default is
         * each event ignored and thus propagated.
         */
        void setAccepted(bool accepted = true) { _accepted = accepted; }

        /** @brief Input text in UTF-8 */
        Containers::ArrayView<const char> text() const { return _text; }

    private:
        friend GlfwApplication;

        explicit TextInputEvent(Containers::ArrayView<const char> text): _text{text}, _accepted{false} {}

        const Containers::ArrayView<const char> _text;
        bool _accepted;
};

/** @hideinitializer
@brief Entry point for GLFW-based applications
@param className Class name

@m_keywords{MAGNUM_APPLICATION_MAIN()}

See @ref Magnum::Platform::GlfwApplication "Platform::GlfwApplication" for
usage information. This macro abstracts out platform-specific entry point code
and is equivalent to the following, see @ref portability-applications for more
information.

@code{.cpp}
int main(int argc, char** argv) {
    className app({argc, argv});
    return app.exec();
}
@endcode

When no other application header is included this macro is also aliased to
@cpp MAGNUM_APPLICATION_MAIN() @ce.
*/
#define MAGNUM_GLFWAPPLICATION_MAIN(className)                              \
    int main(int argc, char** argv) {                                       \
        className app({argc, argv});                                        \
        return app.exec();                                                  \
    }

#ifndef DOXYGEN_GENERATING_OUTPUT
#ifndef MAGNUM_APPLICATION_MAIN
typedef GlfwApplication Application;
typedef BasicScreen<GlfwApplication> Screen;
typedef BasicScreenedApplication<GlfwApplication> ScreenedApplication;
#define MAGNUM_APPLICATION_MAIN(className) MAGNUM_GLFWAPPLICATION_MAIN(className)
#else
#undef MAGNUM_APPLICATION_MAIN
#endif
#endif

}}

#endif