ui: Added scroll speed setting to preferences

src/lib_gui/qt/utility/QtScrollSpeedChangeListener.cpp

@@ -0,0 +1,35 @@
+#include "qt/utility/QtScrollSpeedChangeListener.h"
+
+#include <cmath>
+
+#include <QScrollBar>
+
+#include "settings/ApplicationSettings.h"
+
+QtScrollSpeedChangeListener::QtScrollSpeedChangeListener()
+	: m_changeScrollSpeedFunctor(std::bind(&QtScrollSpeedChangeListener::doChangeScrollSpeed, this, std::placeholders::_1))
+	, m_scrollBar(nullptr)
+	, m_singleStep(1)
+{
+}
+
+void QtScrollSpeedChangeListener::setScrollBar(QScrollBar* scrollbar)
+{
+	m_scrollBar = scrollbar;
+	m_singleStep = scrollbar->singleStep();
+
+	doChangeScrollSpeed(ApplicationSettings::getInstance()->getScrollSpeed());
+}
+
+void QtScrollSpeedChangeListener::handleMessage(MessageScrollSpeedChange* message)
+{
+	m_changeScrollSpeedFunctor(message->scrollSpeed);
+}
+
+void QtScrollSpeedChangeListener::doChangeScrollSpeed(float scrollSpeed)
+{
+	if (m_scrollBar)
+	{
+		m_scrollBar->setSingleStep(std::ceil(m_singleStep * scrollSpeed));
+	}
+}

src/lib_gui/qt/utility/QtScrollSpeedChangeListener.h

@@ -0,0 +1,30 @@
+#ifndef QT_SCROLL_SPEED_CHANGE_LISTENER
+#define QT_SCROLL_SPEED_CHANGE_LISTENER
+
+#include "utility/messaging/MessageListener.h"
+#include "utility/messaging/type/MessageScrollSpeedChange.h"
+
+#include "qt/utility/QtThreadedFunctor.h"
+
+class QScrollBar;
+
+class QtScrollSpeedChangeListener
+	: public MessageListener<MessageScrollSpeedChange>
+{
+public:
+	QtScrollSpeedChangeListener();
+
+	void setScrollBar(QScrollBar* scrollbar);
+
+private:
+	void handleMessage(MessageScrollSpeedChange* message);
+
+	void doChangeScrollSpeed(float scrollSpeed);
+
+	QtThreadedFunctor<float> m_changeScrollSpeedFunctor;
+
+	QScrollBar* m_scrollBar;
+	int m_singleStep;
+};
+
+#endif // QT_SCROLL_SPEED_CHANGE_LISTENER