EventFilter.h

#ifndef EVENTFILTER_HPP__
#define EVENTFILTER_HPP__
 
#include <QEvent>
#include <QKeyEvent>
#include <QMouseEvent>
#include <QObject>
 
#include <functional>
 
namespace EventFilter {
class FocusOut final : public QObject {
  public:
    using Filter = std::function<void()>;
 
    FocusOut(Filter filter, QObject *parent = nullptr)
        : QObject{parent}, filter_{filter} {}
 
    bool eventFilter(QObject *, QEvent *event) override {
        if (event->type() == QEvent::FocusOut)
            filter_();
        return false;
    }
 
  private:
    Filter filter_;
};
 
class EscapeKeyPress final : public QObject {
  public:
    using Filter = std::function<bool(QKeyEvent *)>;
 
    EscapeKeyPress(Filter filter, QObject *parent = nullptr)
        : QObject{parent}, filter_{filter} {}
 
    bool eventFilter(QObject *, QEvent *event) override {
        if (event->type() == QEvent::KeyPress) {
            if (auto const keyEvent = static_cast<QKeyEvent *>(event);
                keyEvent->key() == Qt::Key_Escape) {
                return filter_(keyEvent);
            }
        }
        return false;
    }
 
  private:
    Filter filter_;
};
 
class EnterKeyPress final : public QObject {
  public:
    using Filter = std::function<bool(QKeyEvent *)>;
 
    EnterKeyPress(Filter filter, QObject *parent = nullptr)
        : QObject{parent}, filter_{filter} {}
 
    bool eventFilter(QObject *, QEvent *const event) override {
        if (event->type() == QEvent::KeyPress) {
            if (auto const keyEvent = static_cast<QKeyEvent *>(event);
                keyEvent->key() == Qt::Key_Enter ||
                keyEvent->key() == Qt::Key_Return) {
                return filter_(keyEvent);
            }
        }
        return false;
    }
 
  private:
    Filter filter_;
};
 
class MouseButtonPress final : public QObject {
  public:
    using Filter = std::function<bool(QMouseEvent *)>;
 
    MouseButtonPress(Filter filter, QObject *parent = nullptr)
        : QObject{parent}, filter_{filter} {}
 
    bool eventFilter(QObject *, QEvent *event) override {
        if (event->type() == QEvent::MouseButtonPress) {
            return filter_(static_cast<QMouseEvent *>(event));
        }
        return false;
    }
 
  private:
    Filter filter_;
};
 
class MouseButtonDblClick final : public QObject {
  public:
    using Filter = std::function<bool(QMouseEvent *)>;
 
    MouseButtonDblClick(Filter filter, QObject *parent = nullptr)
        : QObject{parent}, filter_{filter} {}
 
    bool eventFilter(QObject *, QEvent *event) override {
        if (event->type() == QEvent::MouseButtonDblClick) {
            return filter_(static_cast<QMouseEvent *>(event));
        }
        return false;
    }
 
  private:
    Filter filter_;
};
} // namespace EventFilter
 
#endif