diff --git a/doc/changelog.dox b/doc/changelog.dox
index 0618753af..564698968 100644
--- a/doc/changelog.dox
+++ b/doc/changelog.dox
@@ -173,6 +173,9 @@ See also:
 
 @subsubsection changelog-latest-changes-platform Platform libraries
 
+-   @ref Platform::Sdl2Application::viewportEvent() "Platform::*Application::viewportEvent()"
+    now gets all information needed for DPI-aware rendering instead of just
+    a framebuffer size --- now also window size and the DPI scaling value
 -   @ref Platform::GlfwApplication now behaves the same as
     @ref Platform::Sdl2Application when creating an OpenGL context: first it
     attempts to create a forward-compatible core OpenGL 3.2+ context and if
@@ -183,6 +186,9 @@ See also:
     pointer
 -   @ref Platform::GlfwApplication now loads modifiers for mouse move and mouse
     scroll events lazily, only when needed
+-   @ref Platform::BasicScreen::viewportEvent() "Platform::Screen::viewportEvent()"
+    is no longer pure virtual to be consistent with all `*Application`
+    implementations
 
 @subsubsection changelog-latest-changes-shaders Shaders library
 
@@ -271,6 +277,10 @@ See also:
     scheduled for removal in a future release. Please consider switching to
     @ref Platform::Sdl2Application or @ref Platform::GlfwApplication as soon as
     possible.
+-   `Platform::*Application::viewportEvent(const Vector2i&)` is deprecated
+    because it doesn't provide all information needed for DPI-aware rendering.
+    Override the @ref Platform::Sdl2Application::viewportEvent(ViewportEvent&) "viewportEvent(ViewportEvent&)"
+    function instead.
 -   `Math::Geometry`, `Math::Geometry::Distance` and
     `Math::Geometry::Intersection` namespaces are deprecated for being too
     deeply nested, use @ref Math::Distance and @ref Math::Intersection instead
diff --git a/doc/snippets/MagnumGL-framebuffer.cpp b/doc/snippets/MagnumGL-framebuffer.cpp
index 53bf8ec90..7f1267284 100644
--- a/doc/snippets/MagnumGL-framebuffer.cpp
+++ b/doc/snippets/MagnumGL-framebuffer.cpp
@@ -31,8 +31,8 @@ using namespace Magnum;
 
 struct A: Platform::Sdl2Application {
 /* [DefaultFramebuffer-usage-viewport] */
-void viewportEvent(const Vector2i& size) override {
-    GL::defaultFramebuffer.setViewport({{}, size});
+void viewportEvent(ViewportEvent& event) override {
+    GL::defaultFramebuffer.setViewport({{}, event.framebufferSize()});
 
     // ...
 }
diff --git a/doc/snippets/MagnumPlatform-portability.cpp b/doc/snippets/MagnumPlatform-portability.cpp
index 971d50bfb..108e3d76c 100644
--- a/doc/snippets/MagnumPlatform-portability.cpp
+++ b/doc/snippets/MagnumPlatform-portability.cpp
@@ -38,7 +38,7 @@ class MyApplication: public Platform::Application {
         MyApplication(const Arguments& arguments);
 
     protected:
-        void viewportEvent(const Vector2i& size) override;
+        void viewportEvent(ViewportEvent& size) override;
         void drawEvent() override;
         void keyPressEvent(KeyEvent& event) override;
 };
diff --git a/doc/snippets/MagnumPlatform.cpp b/doc/snippets/MagnumPlatform.cpp
index 5a6cdf618..c3f7ce440 100644
--- a/doc/snippets/MagnumPlatform.cpp
+++ b/doc/snippets/MagnumPlatform.cpp
@@ -65,13 +65,13 @@ class MyApplication: public Platform::Application {
     // ...
 
     private:
-        void viewportEvent(const Vector2i& size) override;
+        void viewportEvent(ViewportEvent& event) override;
 };
 
 // ...
 
-void MyApplication::viewportEvent(const Vector2i& size) {
-    GL::defaultFramebuffer.setViewport({{}, size});
+void MyApplication::viewportEvent(ViewportEvent& event) {
+    GL::defaultFramebuffer.setViewport({{}, event.framebufferSize()});
 }
 /* [size] */
 
diff --git a/src/Magnum/Platform/AbstractXApplication.cpp b/src/Magnum/Platform/AbstractXApplication.cpp
index 3b458d5e8..1ab74b5b8 100644
--- a/src/Magnum/Platform/AbstractXApplication.cpp
+++ b/src/Magnum/Platform/AbstractXApplication.cpp
@@ -156,7 +156,8 @@ int AbstractXApplication::exec() {
                     Vector2i size(event.xconfigure.width, event.xconfigure.height);
                     if(size != _windowSize) {
                         _windowSize = size;
-                        viewportEvent(size);
+                        ViewportEvent e{size};
+                        viewportEvent(e);
                         _flags |= Flag::Redraw;
                     }
                 } break;
@@ -190,7 +191,20 @@ int AbstractXApplication::exec() {
     return 0;
 }
 
+void AbstractXApplication::viewportEvent(ViewportEvent& event) {
+    #ifdef MAGNUM_BUILD_DEPRECATED
+    CORRADE_IGNORE_DEPRECATED_PUSH
+    viewportEvent(event.framebufferSize());
+    CORRADE_IGNORE_DEPRECATED_POP
+    #else
+    static_cast<void>(event);
+    #endif
+}
+
+#ifdef MAGNUM_BUILD_DEPRECATED
 void AbstractXApplication::viewportEvent(const Vector2i&) {}
+#endif
+
 void AbstractXApplication::keyPressEvent(KeyEvent&) {}
 void AbstractXApplication::keyReleaseEvent(KeyEvent&) {}
 void AbstractXApplication::mousePressEvent(MouseEvent&) {}
diff --git a/src/Magnum/Platform/AbstractXApplication.h b/src/Magnum/Platform/AbstractXApplication.h
index 284ef6d5f..755cf7dbd 100644
--- a/src/Magnum/Platform/AbstractXApplication.h
+++ b/src/Magnum/Platform/AbstractXApplication.h
@@ -73,6 +73,7 @@ class AbstractXApplication {
 
         class Configuration;
         class GLConfiguration;
+        class ViewportEvent;
         class InputEvent;
         class KeyEvent;
         class MouseEvent;
@@ -211,8 +212,13 @@ class AbstractXApplication {
     #else
     private:
     #endif
-        /** @copydoc Sdl2Application::viewportEvent() */
-        virtual void viewportEvent(const Vector2i& size);
+        /** @copydoc GlfwApplication::viewportEvent(ViewportEvent&) */
+        virtual void viewportEvent(ViewportEvent& event);
+
+        #ifdef MAGNUM_BUILD_DEPRECATED
+        /** @copydoc GlfwApplication::viewportEvent(const Vector2i&) */
+        virtual CORRADE_DEPRECATED("use viewportEvent(ViewportEvent&) instead") void viewportEvent(const Vector2i& size);
+        #endif
 
         /** @copydoc Sdl2Application::drawEvent() */
         virtual void drawEvent() = 0;
@@ -363,6 +369,37 @@ class AbstractXApplication::Configuration {
         #endif
 };
 
+/**
+@brief Viewport event
+
+@see @ref viewportEvent()
+*/
+class AbstractXApplication::ViewportEvent {
+    public:
+        /**
+         * @brief Window size
+         *
+         * Same as @ref framebufferSize().
+         * @see @ref AbstractXApplication::windowSize()
+         */
+        Vector2i windowSize() const { return _size; }
+
+        /**
+         * @brief Framebuffer size
+         *
+         * Same as @ref windowSize().
+         * @see @ref AbstractXApplication::framebufferSize()
+         */
+        Vector2i framebufferSize() const { return _size; }
+
+    private:
+        friend AbstractXApplication;
+
+        explicit ViewportEvent(const Vector2i& size): _size{size} {}
+
+        Vector2i _size;
+};
+
 /**
 @brief Base for input events
 
diff --git a/src/Magnum/Platform/AndroidApplication.cpp b/src/Magnum/Platform/AndroidApplication.cpp
index 48df834a7..448859708 100644
--- a/src/Magnum/Platform/AndroidApplication.cpp
+++ b/src/Magnum/Platform/AndroidApplication.cpp
@@ -174,7 +174,20 @@ void AndroidApplication::swapBuffers() {
     eglSwapBuffers(_display, _surface);
 }
 
+void AndroidApplication::viewportEvent(ViewportEvent& event) {
+    #ifdef MAGNUM_BUILD_DEPRECATED
+    CORRADE_IGNORE_DEPRECATED_PUSH
+    viewportEvent(event.windowSize());
+    CORRADE_IGNORE_DEPRECATED_POP
+    #else
+    static_cast<void>(event);
+    #endif
+}
+
+#ifdef MAGNUM_BUILD_DEPRECATED
 void AndroidApplication::viewportEvent(const Vector2i&) {}
+#endif
+
 void AndroidApplication::mousePressEvent(MouseEvent&) {}
 void AndroidApplication::mouseReleaseEvent(MouseEvent&) {}
 void AndroidApplication::mouseMoveEvent(MouseMoveEvent&) {}
diff --git a/src/Magnum/Platform/AndroidApplication.h b/src/Magnum/Platform/AndroidApplication.h
index ceea514e1..e99e09fa2 100644
--- a/src/Magnum/Platform/AndroidApplication.h
+++ b/src/Magnum/Platform/AndroidApplication.h
@@ -143,6 +143,7 @@ class AndroidApplication {
 
         class Configuration;
         class GLConfiguration;
+        class ViewportEvent;
         class InputEvent;
         class MouseEvent;
         class MouseMoveEvent;
@@ -324,8 +325,13 @@ class AndroidApplication {
     #else
     private:
     #endif
-        /** @copydoc Sdl2Application::viewportEvent() */
-        virtual void viewportEvent(const Vector2i& size);
+        /** @copydoc GlfwApplication::viewportEvent(ViewportEvent&) */
+        virtual void viewportEvent(ViewportEvent& event);
+
+        #ifdef MAGNUM_BUILD_DEPRECATED
+        /** @copydoc GlfwApplication::viewportEvent(const Vector2i&) */
+        virtual CORRADE_DEPRECATED("use viewportEvent(ViewportEvent&) instead") void viewportEvent(const Vector2i& size);
+        #endif
 
         /** @copydoc Sdl2Application::drawEvent() */
         virtual void drawEvent() = 0;
@@ -506,6 +512,28 @@ class AndroidApplication::Configuration {
         Vector2i _size;
 };
 
+/**
+@brief Viewport event
+
+@see @ref viewportEvent()
+*/
+class AndroidApplication::ViewportEvent {
+    public:
+        /**
+         * @brief Window size
+         *
+         * @see @ref AndroidApplication::windowSize()
+         */
+        Vector2i windowSize() const { return _windowSize; }
+
+    private:
+        friend AndroidApplication;
+
+        explicit ViewportEvent(const Vector2i& windowSize): _windowSize{windowSize} {}
+
+        Vector2i _windowSize;
+};
+
 /**
 @brief Base for input events
 
diff --git a/src/Magnum/Platform/GlfwApplication.cpp b/src/Magnum/Platform/GlfwApplication.cpp
index 0fa165605..f3b33d5a6 100644
--- a/src/Magnum/Platform/GlfwApplication.cpp
+++ b/src/Magnum/Platform/GlfwApplication.cpp
@@ -355,7 +355,8 @@ void GlfwApplication::setupCallbacks() {
         static_cast<GlfwApplication*>(glfwGetWindowUserPointer(window))->drawEvent();
     });
     glfwSetFramebufferSizeCallback(_window, [](GLFWwindow* const window, const int w, const int h) {
-        static_cast<GlfwApplication*>(glfwGetWindowUserPointer(window))->viewportEvent({w, h});
+        ViewportEvent e{{w, h}};
+        static_cast<GlfwApplication*>(glfwGetWindowUserPointer(window))->viewportEvent(e);
     });
     glfwSetKeyCallback(_window, [](GLFWwindow* const window, const int key, int, const int action, const int mods) {
         const auto instance = static_cast<GlfwApplication*>(glfwGetWindowUserPointer(window));
@@ -469,7 +470,20 @@ auto GlfwApplication::MouseScrollEvent::modifiers() -> Modifiers {
     return *_modifiers;
 }
 
+void GlfwApplication::viewportEvent(ViewportEvent& event) {
+    #ifdef MAGNUM_BUILD_DEPRECATED
+    CORRADE_IGNORE_DEPRECATED_PUSH
+    viewportEvent(event.windowSize());
+    CORRADE_IGNORE_DEPRECATED_POP
+    #else
+    static_cast<void>(event);
+    #endif
+}
+
+#ifdef MAGNUM_BUILD_DEPRECATED
 void GlfwApplication::viewportEvent(const Vector2i&) {}
+#endif
+
 void GlfwApplication::keyPressEvent(KeyEvent&) {}
 void GlfwApplication::keyReleaseEvent(KeyEvent&) {}
 void GlfwApplication::mousePressEvent(MouseEvent&) {}
diff --git a/src/Magnum/Platform/GlfwApplication.h b/src/Magnum/Platform/GlfwApplication.h
index 7e89a871a..10231969e 100644
--- a/src/Magnum/Platform/GlfwApplication.h
+++ b/src/Magnum/Platform/GlfwApplication.h
@@ -130,6 +130,7 @@ class GlfwApplication {
         #ifdef MAGNUM_TARGET_GL
         class GLConfiguration;
         #endif
+        class ViewportEvent;
         class InputEvent;
         class KeyEvent;
         class MouseEvent;
@@ -365,8 +366,37 @@ class GlfwApplication {
     #else
     private:
     #endif
-        /** @copydoc Sdl2Application::viewportEvent() */
-        virtual void viewportEvent(const Vector2i& size);
+        /**
+         * @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 also using @ref windowSize().
+         *
+         * @todoc make this a copydoc of Sdl2Application once both have
+         *      framebufferSize() and dpiScaling()
+         */
+        virtual void viewportEvent(ViewportEvent& event);
+
+        #ifdef MAGNUM_BUILD_DEPRECATED
+        /** @brief @copybrief viewportEvent(ViewportEvent&)
+         * @deprecated 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;
@@ -862,6 +892,28 @@ class GlfwApplication::Configuration {
 
 CORRADE_ENUMSET_OPERATORS(GlfwApplication::Configuration::WindowFlags)
 
+/**
+@brief Viewport event
+
+@see @ref viewportEvent()
+*/
+class GlfwApplication::ViewportEvent {
+    public:
+        /**
+         * @brief Window size
+         *
+         * @see @ref GlfwApplication::windowSize()
+         */
+        Vector2i windowSize() const { return _windowSize; }
+
+    private:
+        friend GlfwApplication;
+
+        explicit ViewportEvent(const Vector2i& windowSize): _windowSize{windowSize} {}
+
+        Vector2i _windowSize;
+};
+
 /**
 @brief Base for input events
 
diff --git a/src/Magnum/Platform/GlutApplication.cpp b/src/Magnum/Platform/GlutApplication.cpp
index abc3304ba..cb11c27d9 100644
--- a/src/Magnum/Platform/GlutApplication.cpp
+++ b/src/Magnum/Platform/GlutApplication.cpp
@@ -134,6 +134,11 @@ bool GlutApplication::tryCreate(const Configuration& configuration, const GLConf
 
 GlutApplication::~GlutApplication() = default;
 
+void GlutApplication::staticViewportEvent(int x, int y) {
+    ViewportEvent e{{x, y}};
+    _instance->viewportEvent(e);
+}
+
 void GlutApplication::staticKeyPressEvent(unsigned char key, int x, int y) {
     KeyEvent e(static_cast<KeyEvent::Key>(key), {x, y});
     _instance->keyPressEvent(e);
@@ -167,7 +172,20 @@ void GlutApplication::staticMouseMoveEvent(int x, int y) {
     _instance->mouseMoveEvent(e);
 }
 
+void GlutApplication::viewportEvent(ViewportEvent& event) {
+    #ifdef MAGNUM_BUILD_DEPRECATED
+    CORRADE_IGNORE_DEPRECATED_PUSH
+    viewportEvent(event.windowSize());
+    CORRADE_IGNORE_DEPRECATED_POP
+    #else
+    static_cast<void>(event);
+    #endif
+}
+
+#ifdef MAGNUM_BUILD_DEPRECATED
 void GlutApplication::viewportEvent(const Vector2i&) {}
+#endif
+
 void GlutApplication::keyPressEvent(KeyEvent&) {}
 void GlutApplication::keyReleaseEvent(KeyEvent&) {}
 void GlutApplication::mousePressEvent(MouseEvent&) {}
diff --git a/src/Magnum/Platform/GlutApplication.h b/src/Magnum/Platform/GlutApplication.h
index 6441a6c10..ff65dcced 100644
--- a/src/Magnum/Platform/GlutApplication.h
+++ b/src/Magnum/Platform/GlutApplication.h
@@ -134,6 +134,7 @@ class CORRADE_DEPRECATED("Scheduled for removal. Consider switching to Sdl2Appli
 
         class Configuration;
         class GLConfiguration;
+        class ViewportEvent;
         class InputEvent;
         class KeyEvent;
         class MouseEvent;
@@ -300,8 +301,33 @@ class CORRADE_DEPRECATED("Scheduled for removal. Consider switching to Sdl2Appli
     #else
     private:
     #endif
-        /** @copydoc Sdl2Application::viewportEvent() */
-        virtual void viewportEvent(const Vector2i& size);
+        /**
+         * @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.
+         */
+        virtual void viewportEvent(ViewportEvent& event);
+
+        #ifdef MAGNUM_BUILD_DEPRECATED
+        /** @brief @copybrief viewportEvent(ViewportEvent&)
+         * @deprecated 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;
@@ -374,9 +400,7 @@ class CORRADE_DEPRECATED("Scheduled for removal. Consider switching to Sdl2Appli
         /*@}*/
 
     private:
-        static void staticViewportEvent(int x, int y) {
-            _instance->viewportEvent({x, y});
-        }
+        static void staticViewportEvent(int x, int y);
 
         static void staticKeyPressEvent(unsigned char key, int x, int y);
         static void staticKeyReleaseEvent(unsigned char key, int x, int y);
@@ -587,6 +611,24 @@ class GlutApplication::Configuration {
         #endif
 };
 
+/**
+@brief Viewport event
+
+@see @ref viewportEvent()
+*/
+class GlutApplication::ViewportEvent {
+    public:
+        /** @brief Window size */
+        Vector2i windowSize() const { return _windowSize; }
+
+    private:
+        friend GlutApplication;
+
+        explicit ViewportEvent(const Vector2i& windowSize): _windowSize{windowSize} {}
+
+        Vector2i _windowSize;
+};
+
 /**
 @brief Base for input events
 
diff --git a/src/Magnum/Platform/Screen.h b/src/Magnum/Platform/Screen.h
index f1615ffa6..a879acd9d 100644
--- a/src/Magnum/Platform/Screen.h
+++ b/src/Magnum/Platform/Screen.h
@@ -102,6 +102,9 @@ template<class Application> class BasicScreen: private Containers::LinkedListIte
         typedef Implementation::PropagatedScreenEvents PropagatedEvents;
         #endif
 
+        /** @brief Viewport event */
+        typedef typename BasicScreenedApplication<Application>::ViewportEvent ViewportEvent;
+
         /** @brief Input event */
         typedef typename BasicScreenedApplication<Application>::InputEvent InputEvent;
 
@@ -197,7 +200,19 @@ template<class Application> class BasicScreen: private Containers::LinkedListIte
          * for more information. Setting viewport on default framebuffer should
          * be done by the holder application.
          */
-        virtual void viewportEvent(const Vector2i& size) = 0;
+        virtual void viewportEvent(ViewportEvent& event);
+
+        #ifdef MAGNUM_BUILD_DEPRECATED
+        /** @brief @copybrief viewportEvent(ViewportEvent&)
+         * @deprecated Use @ref viewportEvent(ViewportEvent&) instead.
+         *      To preserve backwards compatibility, this function is called
+         *      from @ref viewportEvent(ViewportEvent&) with
+         *      @ref Sdl2Application::ViewportEvent::windowSize() "*Application::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
 
         /**
          * @brief Draw event
diff --git a/src/Magnum/Platform/ScreenedApplication.h b/src/Magnum/Platform/ScreenedApplication.h
index 551001bec..c9174bcf4 100644
--- a/src/Magnum/Platform/ScreenedApplication.h
+++ b/src/Magnum/Platform/ScreenedApplication.h
@@ -204,7 +204,7 @@ template<class Application> class BasicScreenedApplication: public Application,
          * implementation does nothing. See @ref Sdl2Application::viewportEvent() "*Application::viewportEvent()"
          * for more information.
          */
-        virtual void globalViewportEvent(const Vector2i& size);
+        virtual void globalViewportEvent(typename Application::ViewportEvent& size);
 
         /**
          * @brief Draw event
@@ -222,11 +222,10 @@ template<class Application> class BasicScreenedApplication: public Application,
         friend Containers::LinkedListItem<BasicScreen<Application>, BasicScreenedApplication<Application>>;
         friend BasicScreen<Application>;
         #endif
-
         /* The user is supposed to override only globalViewportEvent() and
            globalDrawEvent(), these implementations are dispatching the events
            to attached screens. */
-        void viewportEvent(const Vector2i& size) override final;
+        void viewportEvent(typename Application::ViewportEvent& event) override final;
         void drawEvent() override final;
         void keyPressEvent(typename Application::KeyEvent& event) override final;
         void keyReleaseEvent(typename Application::KeyEvent& event) override final;
diff --git a/src/Magnum/Platform/ScreenedApplication.hpp b/src/Magnum/Platform/ScreenedApplication.hpp
index e1fb5c1b2..98d6b1435 100644
--- a/src/Magnum/Platform/ScreenedApplication.hpp
+++ b/src/Magnum/Platform/ScreenedApplication.hpp
@@ -37,6 +37,20 @@ namespace Magnum { namespace Platform {
 template<class Application> BasicScreen<Application>::BasicScreen() = default;
 template<class Application> BasicScreen<Application>::~BasicScreen() = default;
 
+template<class Application> void BasicScreen<Application>::viewportEvent(ViewportEvent& event) {
+    #ifdef MAGNUM_BUILD_DEPRECATED
+    CORRADE_IGNORE_DEPRECATED_PUSH
+    viewportEvent(event.windowSize());
+    CORRADE_IGNORE_DEPRECATED_POP
+    #else
+    static_cast<void>(event);
+    #endif
+}
+
+#ifdef MAGNUM_BUILD_DEPRECATED
+template<class Application> void BasicScreen<Application>::viewportEvent(const Vector2i&) {}
+#endif
+
 template<class Application> void BasicScreen<Application>::keyPressEvent(KeyEvent&) {}
 template<class Application> void BasicScreen<Application>::keyReleaseEvent(KeyEvent&) {}
 template<class Application> void BasicScreen<Application>::mousePressEvent(MouseEvent&) {}
@@ -78,13 +92,13 @@ template<class Application> BasicScreenedApplication<Application>& BasicScreened
     return *this;
 }
 
-template<class Application> void BasicScreenedApplication<Application>::globalViewportEvent(const Vector2i&) {}
+template<class Application> void BasicScreenedApplication<Application>::globalViewportEvent(typename Application::ViewportEvent&) {}
 
-template<class Application> void BasicScreenedApplication<Application>::viewportEvent(const Vector2i& size) {
+template<class Application> void BasicScreenedApplication<Application>::viewportEvent(typename Application::ViewportEvent& event) {
     /* Call global event before all other (to resize framebuffer first) */
-    globalViewportEvent(size);
+    globalViewportEvent(event);
 
-    for(BasicScreen<Application>& s: *this) s.viewportEvent(size);
+    for(BasicScreen<Application>& s: *this) s.viewportEvent(event);
 }
 
 template<class Application> void BasicScreenedApplication<Application>::drawEvent() {
diff --git a/src/Magnum/Platform/Sdl2Application.cpp b/src/Magnum/Platform/Sdl2Application.cpp
index af7b37d22..52e6de855 100644
--- a/src/Magnum/Platform/Sdl2Application.cpp
+++ b/src/Magnum/Platform/Sdl2Application.cpp
@@ -573,15 +573,9 @@ void Sdl2Application::mainLoopIteration() {
             case SDL_WINDOWEVENT:
                 switch(event.window.event) {
                     case SDL_WINDOWEVENT_RESIZED: {
-                        #ifndef CORRADE_TARGET_IOS
-                        viewportEvent({event.window.data1, event.window.data2});
-                        #else
-                        /* On iOS the window event is in points and not pixels,
-                           but we need pixels to call glViewport() properly */
-                        Vector2i drawableSize;
-                        SDL_GL_GetDrawableSize(_window, &drawableSize.x(), &drawableSize.y());
-                        viewportEvent(drawableSize);
-                        #endif
+                        ViewportEvent e{{event.window.data1, event.window.data2}, framebufferSize(), _dpiScaling};
+                        /** @todo handle also WM_DPICHANGED events when a window is moved between displays with different DPI */
+                        viewportEvent(e);
                         _flags |= Flag::Redraw;
                     } break;
                     case SDL_WINDOWEVENT_EXPOSED:
@@ -738,7 +732,20 @@ void Sdl2Application::tickEvent() {
     _flags |= Flag::NoTickEvent;
 }
 
+void Sdl2Application::viewportEvent(ViewportEvent& event) {
+    #ifdef MAGNUM_BUILD_DEPRECATED
+    CORRADE_IGNORE_DEPRECATED_PUSH
+    viewportEvent(event.framebufferSize());
+    CORRADE_IGNORE_DEPRECATED_POP
+    #else
+    static_cast<void>(event);
+    #endif
+}
+
+#ifdef MAGNUM_BUILD_DEPRECATED
 void Sdl2Application::viewportEvent(const Vector2i&) {}
+#endif
+
 void Sdl2Application::keyPressEvent(KeyEvent&) {}
 void Sdl2Application::keyReleaseEvent(KeyEvent&) {}
 void Sdl2Application::mousePressEvent(MouseEvent&) {}
diff --git a/src/Magnum/Platform/Sdl2Application.h b/src/Magnum/Platform/Sdl2Application.h
index e9de03375..db1c55033 100644
--- a/src/Magnum/Platform/Sdl2Application.h
+++ b/src/Magnum/Platform/Sdl2Application.h
@@ -339,6 +339,7 @@ class Sdl2Application {
         #ifdef MAGNUM_TARGET_GL
         class GLConfiguration;
         #endif
+        class ViewportEvent;
         class InputEvent;
         class KeyEvent;
         class MouseEvent;
@@ -682,17 +683,34 @@ class Sdl2Application {
          *
          * 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...).
+         * new *framebuffer* size to @ref GL::DefaultFramebuffer::setViewport()
+         * (if using OpenGL) and possibly elsewhere (to
+         * @ref SceneGraph::Camera::setViewport(), other framebuffers...) and
+         * the new *window* size and DPI scaling to APIs that respond to user
+         * events or scale UI elements.
          *
          * 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. Viewport of default
-         * framebuffer can be retrieved via @ref GL::DefaultFramebuffer::viewport().
+         * 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-Sdl2Application-dpi for detailed info about these
+         * values.
          */
-        virtual void viewportEvent(const Vector2i& size);
+        virtual void viewportEvent(ViewportEvent& event);
+
+        #ifdef MAGNUM_BUILD_DEPRECATED
+        /** @brief @copybrief viewportEvent(ViewportEvent&)
+         * @deprecated Use @ref viewportEvent(ViewportEvent&) instead.
+         *      To preserve backwards compatibility, this function is called
+         *      from @ref viewportEvent(ViewportEvent&) with
+         *      @ref ViewportEvent::framebufferSize() 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
 
         /**
          * @brief Draw event
@@ -1432,6 +1450,53 @@ class Sdl2Application::Configuration {
         #endif
 };
 
+/**
+@brief Viewport event
+
+@see @ref viewportEvent()
+*/
+class Sdl2Application::ViewportEvent {
+    public:
+        /**
+         * @brief Window size
+         *
+         * On some platforms with HiDPI displays, window size can be different
+         * from @ref framebufferSize(). See @ref Platform-Sdl2Application-dpi
+         * for more information.
+         * @see @ref Sdl2Application::windowSize()
+         */
+        Vector2i windowSize() const { return _windowSize; }
+
+        /**
+         * @brief Framebuffer size
+         *
+         * On some platforms with HiDPI displays, framebuffer size can be
+         * different from @ref windowSize(). See
+         * @ref Platform-Sdl2Application-dpi for more information.
+         * @see @ref Sdl2Application::framebufferSize()
+         */
+        Vector2i framebufferSize() const { return _framebufferSize; }
+
+        /**
+         * @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-Sdl2Application-dpi for more information.
+         * @see @ref Sdl2Application::dpiScaling()
+         */
+        Vector2 dpiScaling() const { return _dpiScaling; }
+
+    private:
+        friend Sdl2Application;
+
+        explicit ViewportEvent(const Vector2i& windowSize, const Vector2i& framebufferSize, const Vector2& dpiScaling): _windowSize{windowSize}, _framebufferSize{framebufferSize}, _dpiScaling{dpiScaling} {}
+
+        Vector2i _windowSize, _framebufferSize;
+        Vector2 _dpiScaling;
+};
+
 /**
 @brief Base for input events