TWheelFocusEvent.h

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#pragma once
 
#include <QtWidgets/QWidget>
#include <QtCore/QEvent>
#include <QtWidgets/QAbstractSpinBox>
#include <QtWidgets/QSlider>
#include <QtWidgets/QDial>
#include <QtWidgets/QAbstractItemView>
#include <QtWidgets/QComboBox>
 
 
namespace iqtgui
{
 
 
// static functions
 
inline static void InstallWheelEventFilter(QObject* filterPtr, QWidget* parentPtr)
{
       if (!parentPtr) {
              return;
       }
 
       auto childrenList = parentPtr->findChildren<QWidget*>();
       for (auto it : childrenList)
       {
              if (auto viewPtr = dynamic_cast<QAbstractItemView*>(it))
              {
                     viewPtr->viewport()->installEventFilter(filterPtr);
                     continue;
              }
 
              if (dynamic_cast<QAbstractSpinBox*>(it) ||
                     dynamic_cast<QSlider*>(it) ||
                     dynamic_cast<QDial*>(it) ||
                     dynamic_cast<QComboBox*>(it))
              {
                     it->installEventFilter(filterPtr);
                     it->setFocusPolicy(Qt::StrongFocus);
                     continue;
              }
       }
}
 
 
inline static bool HandleWheelEvent(QObject* object, QEvent* event)
{
       // #10124: if the event is a wheel event and the editor does not have focus, ignore it
       // this is needed to prevent the wheel event from being passed to the parent widget
       // which may cause unwanted behavior (e.g. scrolling in a table view)
       // this is needed for all widgets that are not ACF classes (e.g. QSpinBox, QSlider, etc.)
 
       if (event->type() == QEvent::Wheel) {
              if (auto editorPtr = dynamic_cast<QWidget*>(object)) {
                     if (!editorPtr->hasFocus()) {
                            return true;
                     }
              }
       }
 
       return false;
}
 
 
// use this class to install event filter for wheel events for non-ACF classes
 
template<class Widget = QWidget>
class TWheelFocusEventFilter : public Widget
{
public:
       TWheelFocusEventFilter(QWidget* parent = nullptr) : Widget(parent) 
       {}
 
protected:
       // reimplemented (QObject)
       virtual bool eventFilter(QObject* object, QEvent* event) override
       {
              // #10124
              if (HandleWheelEvent(object, event)) {
                     return true;
              }
              else
                     // pass the event to the parent class
                     return Widget::eventFilter(object, event);
       }
};
 
 
 
// use this class to install event filter for wheel events for ACF classes
 
template<class GUIClass>
class TWheelFocusEvent : public GUIClass
{
public:
       typedef GUIClass BaseClass;
 
       // reimplemented (iqtgui::CGuiComponentBase)
       virtual void OnGuiCreated() override
       {
              BaseClass::OnGuiCreated();
              
              // install event filter for wheel events
              InstallWheelEventFilter(this, GUIClass::GetQtWidget());
       }
 
protected:
       // reimplemented (QObject)
       virtual bool eventFilter(QObject* object, QEvent* event) override
       {
              // #10124
              if (HandleWheelEvent(object, event)) {
                     return true;
              }
              else
                     // pass the event to the parent class
                     return BaseClass::eventFilter(object, event);
       }
};
 
 
} // ns