python: implement basic mouse events for SDL2 and GLFW apps.

This took a while because I wasn't able to convince pybind to do what I
want.

src/python/magnum/platform/application.h

@@ -25,6 +25,7 @@
 
 #include <pybind11/pybind11.h>
 
+#include "corrade/EnumOperators.h"
 #include "magnum/bootstrap.h"
 
 namespace magnum { namespace platform {
@@ -62,11 +63,42 @@ template<class T, class Trampoline> void application(py::class_<T, Trampoline>&
         .def("swap_buffers", &T::swapBuffers, "Swap buffers")
         /** @todo setMinimalLoopPeriod, needs a getter */
         .def("redraw", &T::redraw, "Redraw immediately")
+        .def("window_size", &T::windowSize, "Window size")
+        .def("framebuffer_size", &T::framebufferSize, "Framebuffer size")
 
         /* Event handlers */
         .def("draw_event", &T::drawEvent, "Draw event")
+        .def("mouse_press_event", &T::mousePressEvent, "Mouse press event")
+        .def("mouse_release_event", &T::mouseReleaseEvent, "Mouse release event")
+        .def("mouse_move_event", &T::mouseMoveEvent, "Mouse move event")
         /** @todo more */
         ;
 }
 
+template<class T> void mouseEvent(py::class_<T>& c) {
+    py::enum_<typename T::Button>{c, "Button", "Mouse button"}
+        .value("LEFT", T::Button::Left)
+        .value("MIDDLE", T::Button::Middle)
+        .value("RIGHT", T::Button::Right);
+
+    c
+        .def_property_readonly("button", &T::button, "Button")
+        .def_property_readonly("position", &T::position, "Position");
+}
+
+template<class T> void mouseMoveEvent(py::class_<T>& c) {
+    py::enum_<typename T::Button> buttons{c, "Buttons", "Set of mouse buttons"};
+    buttons
+        .value("LEFT", T::Button::Left)
+        .value("MIDDLE", T::Button::Middle)
+        .value("RIGHT", T::Button::Right);
+    corrade::enumOperators(buttons);
+
+    c
+        .def_property_readonly("position", &T::position, "Position")
+        .def_property_readonly("buttons", [](T& self) {
+            return typename T::Button(typename std::underlying_type<typename T::Button>::type(self.buttons()));
+        }, "Mouse buttons");
+}
+
 }}

src/python/magnum/platform/glfw.cpp

@@ -38,6 +38,9 @@ void glfw(py::module& m) {
         explicit PublicizedApplication(const Configuration& configuration, const GLConfiguration& glConfiguration): Platform::Application{Arguments{argc, nullptr}, configuration, glConfiguration} {}
 
         void drawEvent() override = 0;
+        void mousePressEvent(MouseEvent&) override {}
+        void mouseReleaseEvent(MouseEvent&) override {}
+        void mouseMoveEvent(MouseMoveEvent&) override {}
     };
 
     struct PyApplication: PublicizedApplication {
@@ -51,12 +54,53 @@ void glfw(py::module& m) {
                 drawEvent
             );
         }
+
+        void mousePressEvent(MouseEvent& event) override {
+            PYBIND11_OVERLOAD_NAME(
+                void,
+                PublicizedApplication,
+                "mouse_press_event",
+                mousePressEvent,
+                /* Have to use std::ref() otherwise pybind tries to copy
+                   it and fails */
+                std::ref(event)
+            );
+        }
+
+        void mouseReleaseEvent(MouseEvent& event) override {
+            PYBIND11_OVERLOAD_NAME(
+                void,
+                PublicizedApplication,
+                "mouse_release_event",
+                mouseReleaseEvent,
+                /* Have to use std::ref() otherwise pybind tries to copy
+                   it and fails */
+                std::ref(event)
+            );
+        }
+
+        void mouseMoveEvent(MouseMoveEvent& event) override {
+            PYBIND11_OVERLOAD_NAME(
+                void,
+                PublicizedApplication,
+                "mouse_move_event",
+                mouseMoveEvent,
+                /* Have to use std::ref() otherwise pybind tries to copy
+                   it and fails */
+                std::ref(event)
+            );
+        }
     };
 
     py::class_<PublicizedApplication, PyApplication> glfwApplication{m, "Application", "GLFW application"};
     /** @todo def_property_writeonly for swap_interval */
 
+    py::class_<PyApplication::MouseEvent> mouseEvent_{glfwApplication, "MouseEvent", "Mouse event"};
+    py::class_<PyApplication::MouseMoveEvent> mouseMoveEvent_{glfwApplication, "MouseMoveEvent", "Mouse move event"};
+
     application(glfwApplication);
+    mouseEvent(mouseEvent_);
+    mouseMoveEvent(mouseMoveEvent_);
 }
 
 }}}

src/python/magnum/platform/sdl2.cpp

@@ -38,6 +38,9 @@ void sdl2(py::module& m) {
         explicit PublicizedApplication(const Configuration& configuration, const GLConfiguration& glConfiguration): Platform::Application{Arguments{argc, nullptr}, configuration, glConfiguration} {}
 
         void drawEvent() override = 0;
+        void mousePressEvent(MouseEvent&) override {}
+        void mouseReleaseEvent(MouseEvent&) override {}
+        void mouseMoveEvent(MouseMoveEvent&) override {}
     };
 
     struct PyApplication: PublicizedApplication {
@@ -51,6 +54,46 @@ void sdl2(py::module& m) {
                 drawEvent
             );
         }
+
+        /* PYBIND11_OVERLOAD_NAME() calls object_api::operator() with implicit
+           template param, which is return_value_policy::automatic_reference.
+           That later gets changed to return_value_policy::copy in
+           type_caster_base::cast() and there's no way to override that  */
+        void mousePressEvent(MouseEvent& event) override {
+            PYBIND11_OVERLOAD_NAME(
+                void,
+                PublicizedApplication,
+                "mouse_press_event",
+                mousePressEvent,
+                /* Have to use std::ref() otherwise pybind tries to copy
+                   it and fails */
+                std::ref(event)
+            );
+        }
+
+        void mouseReleaseEvent(MouseEvent& event) override {
+            PYBIND11_OVERLOAD_NAME(
+                void,
+                PublicizedApplication,
+                "mouse_release_event",
+                mouseReleaseEvent,
+                /* Have to use std::ref() otherwise pybind tries to copy
+                   it and fails */
+                std::ref(event)
+            );
+        }
+
+        void mouseMoveEvent(MouseMoveEvent& event) override {
+            PYBIND11_OVERLOAD_NAME(
+                void,
+                PublicizedApplication,
+                "mouse_move_event",
+                mouseMoveEvent,
+                /* Have to use std::ref() otherwise pybind tries to copy
+                   it and fails */
+                std::ref(event)
+            );
+        }
     };
 
     py::class_<PublicizedApplication, PyApplication> sdl2application{m, "Application", "SDL2 application"};
@@ -60,7 +103,12 @@ void sdl2(py::module& m) {
                 self.setSwapInterval(interval);
             }, "Swap interval");
 
+    py::class_<PublicizedApplication::MouseEvent> mouseEvent_{sdl2application, "MouseEvent", "Mouse event"};
+    py::class_<PublicizedApplication::MouseMoveEvent> mouseMoveEvent_{sdl2application, "MouseMoveEvent", "Mouse move event"};
+
     application(sdl2application);
+    mouseEvent(mouseEvent_);
+    mouseMoveEvent(mouseMoveEvent_);
 }
 
 }}}