Platform: added Sdl2Application::multiGestureEvent().

src/Magnum/Platform/Sdl2Application.cpp

@@ -390,6 +390,12 @@ void Sdl2Application::mainLoop() {
                 break;
             }
 
+            case SDL_MULTIGESTURE: {
+                MultiGestureEvent e({event.mgesture.x, event.mgesture.y}, event.mgesture.dTheta, event.mgesture.dDist, event.mgesture.numFingers);
+                multiGestureEvent(e);
+                break;
+            }
+
             #ifndef CORRADE_TARGET_EMSCRIPTEN
             case SDL_TEXTINPUT: {
                 TextInputEvent e{{event.text.text, std::strlen(event.text.text)}};
@@ -476,6 +482,7 @@ void Sdl2Application::keyReleaseEvent(KeyEvent&) {}
 void Sdl2Application::mousePressEvent(MouseEvent&) {}
 void Sdl2Application::mouseReleaseEvent(MouseEvent&) {}
 void Sdl2Application::mouseMoveEvent(MouseMoveEvent&) {}
+void Sdl2Application::multiGestureEvent(MultiGestureEvent&) {}
 void Sdl2Application::textInputEvent(TextInputEvent&) {}
 void Sdl2Application::textEditingEvent(TextEditingEvent&) {}
 

src/Magnum/Platform/Sdl2Application.h

@@ -331,6 +331,7 @@ class Sdl2Application {
         class KeyEvent;
         class MouseEvent;
         class MouseMoveEvent;
+        class MultiGestureEvent;
         class TextInputEvent;
         class TextEditingEvent;
 
@@ -583,6 +584,19 @@ class Sdl2Application {
 
         /*@}*/
 
+        /** @{ @name Touch gesture handling */
+
+        /**
+         * @brief Multi gesture event
+         *
+         * Called when the user performs a gesture using multiple fingers.
+         * Default implementation does nothing.
+         * @experimental
+         */
+        virtual void multiGestureEvent(MultiGestureEvent& event);
+
+        /*@}*/
+
         /** @{ @name Text input handling */
     public:
         /**
@@ -1210,6 +1224,75 @@ class Sdl2Application::MouseMoveEvent: public Sdl2Application::InputEvent {
         Modifiers _modifiers;
 };
 
+/**
+@brief Multi gesture event
+
+@experimental
+@see @ref multiGestureEvent()
+*/
+class Sdl2Application::MultiGestureEvent {
+    friend Sdl2Application;
+
+    public:
+        /** @brief Copying is not allowed */
+        MultiGestureEvent(const MultiGestureEvent&) = delete;
+
+        /** @brief Moving is not allowed */
+        MultiGestureEvent(MultiGestureEvent&&) = delete;
+
+        /** @brief Copying is not allowed */
+        MultiGestureEvent& operator=(const MultiGestureEvent&) = delete;
+
+        /** @brief Moving is not allowed */
+        MultiGestureEvent& operator=(MultiGestureEvent&&) = delete;
+
+        /** @brief Whether the event is accepted */
+        constexpr 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 Gesture center */
+        Vector2 center() const { return _center; }
+
+        /**
+         * @brief Relative rotation
+         *
+         * Rotation relative to previous event.
+         */
+        Float relativeRotation() const { return _relativeRotation; }
+
+        /**
+         * @brief Relative distance
+         *
+         * Distance of the fingers relative to previous event.
+         */
+        Float relativeDistance() const { return _relativeDistance; }
+
+        /**
+         * @brief Finger count
+         *
+         * Count of fingers performing the gesture.
+         */
+        Int fingerCount() const { return _fingerCount; }
+
+    private:
+        constexpr MultiGestureEvent(const Vector2& center, Float relativeRotation, Float relativeDistance, Int fingerCount): _center{center}, _relativeRotation{relativeRotation}, _relativeDistance{relativeDistance}, _fingerCount{fingerCount}, _accepted{false} {}
+
+        Vector2 _center;
+        Float _relativeRotation,
+            _relativeDistance;
+        Int _fingerCount;
+        bool _accepted;
+};
+
 /**
 @brief Text input event