Gui: Pass wheel event to viewprovider

=====================================

https://forum.freecadweb.org/viewtopic.php?p=578857#p578857

src/Gui/NavigationStyle.cpp

@@ -1493,14 +1493,17 @@ SbBool NavigationStyle::processEvent(const SoEvent * const ev)
 SbBool NavigationStyle::processSoEvent(const SoEvent * const ev)
 {
     bool processed = false;
+    bool offeredtoViewerEventBase = false;
 
     //handle mouse wheel zoom
     if (ev->isOfType(SoMouseWheelEvent::getClassTypeId())) {
         const SoMouseWheelEvent * const event = static_cast<const SoMouseWheelEvent *>(ev);
         processed = processWheelEvent(event);
+        viewer->processSoEventBase(ev);
+        offeredtoViewerEventBase = true;
     }
 
-    if (!processed) {
+    if (!processed && !offeredtoViewerEventBase) {
         processed = viewer->processSoEventBase(ev);
     }
 

src/Gui/ViewProvider.cpp

@@ -41,6 +41,7 @@
 #include <Base/Exception.h>
 #include <Base/Matrix.h>
 
+#include "SoMouseWheelEvent.h"
 #include "ViewProvider.h"
 #include "ActionFunction.h"
 #include "Application.h"
@@ -217,7 +218,7 @@ void ViewProvider::eventCallback(void * ud, SoEventCallback * node)
                     // Therefore, we shall ignore ESC while any mouse button is
                     // pressed, until this Coin bug is fixed.
                     if (!press) {
-                        // react only on key release 
+                        // react only on key release
                         // Let first selection mode terminate
                         Gui::Document* doc = Gui::Application::Instance->activeDocument();
                         Gui::View3DInventor* view = static_cast<Gui::View3DInventor*>(doc->getActiveView());
@@ -229,7 +230,7 @@ void ViewProvider::eventCallback(void * ud, SoEventCallback * node)
                                 return;
                             }
                         }
-                        
+
                         Gui::TimerFunction* func = new Gui::TimerFunction();
                         func->setAutoDelete(true);
                         func->setFunction(boost::bind(&Document::resetEdit, doc));
@@ -258,6 +259,12 @@ void ViewProvider::eventCallback(void * ud, SoEventCallback * node)
             if (self->mouseButtonPressed(button,press,ev->getPosition(),viewer))
                 node->setHandled();
         }
+        else if (ev->getTypeId().isDerivedFrom(SoMouseWheelEvent::getClassTypeId())) {
+            const SoMouseWheelEvent * const event = (const SoMouseWheelEvent *) ev;
+
+            if (self->mouseWheelEvent(event->getDelta(), event->getPosition(), viewer))
+                node->setHandled();
+        }
         // Mouse Movement handling
         else if (ev->getTypeId().isDerivedFrom(SoLocation2Event::getClassTypeId())) {
             if (self->mouseMove(ev->getPosition(),viewer))
@@ -670,6 +677,14 @@ bool ViewProvider::mouseButtonPressed(int button, bool pressed,
     return false;
 }
 
+bool ViewProvider::mouseWheelEvent(int delta, const SbVec2s &cursorPos, const View3DInventorViewer* viewer)
+{
+    (void) delta;
+    (void) cursorPos;
+    (void) viewer;
+    return false;
+}
+
 void ViewProvider::setupContextMenu(QMenu* menu, QObject* receiver, const char* method)
 {
     auto vector = getExtensionsDerivedFromType<Gui::ViewProviderExtension>();

src/Gui/ViewProvider.h

@@ -468,6 +468,8 @@ public:
     /// is called when the Provider is in edit and the mouse is clicked
     virtual bool mouseButtonPressed(int button, bool pressed, const SbVec2s &cursorPos,
                                     const View3DInventorViewer* viewer);
+
+    virtual bool mouseWheelEvent(int delta, const SbVec2s &cursorPos, const View3DInventorViewer* viewer);
     /// set up the context-menu with the supported edit modes
     virtual void setupContextMenu(QMenu*, QObject*, const char*);