ui: Improved code view UI

* reduced minimized file state to one-colored block
* added hover states to file buttons
* show hover state when hovering title bar
* fixed file button use for overview stats snippet

src/lib_gui/qt/element/QtIconButton.h

@@ -3,6 +3,24 @@
 
 #include <QPushButton>
 
+class QtHoverButton
+	: public QPushButton
+{
+	Q_OBJECT
+
+public:
+	QtHoverButton(QWidget* parent = nullptr);
+
+signals:
+	void hoveredIn(QPushButton*);
+	void hoveredOut(QPushButton*);
+
+protected:
+	void enterEvent(QEvent *event);
+	void leaveEvent(QEvent *event);
+};
+
+
 class QtIconButton
 	: public QPushButton
 {
@@ -24,4 +42,46 @@ private:
 	QColor m_color;
 };
 
+
+class QtIconStateButton
+	: public QPushButton
+{
+	Q_OBJECT
+
+public:
+	enum ButtonState
+	{
+		STATE_DEFAULT,
+		STATE_HOVERED,
+		STATE_DISABLED
+	};
+
+	struct State
+	{
+		QString iconPath;
+		QColor color;
+	};
+
+	QtIconStateButton(QWidget* parent = nullptr);
+
+	void addState(ButtonState buttonState, QString iconPath, QColor color = Qt::transparent);
+
+	void hoverIn();
+	void hoverOut();
+
+signals:
+	void hoveredIn(QPushButton*);
+	void hoveredOut(QPushButton*);
+
+protected:
+	void changeEvent(QEvent *event);
+	void enterEvent(QEvent *event);
+	void leaveEvent(QEvent *event);
+
+private:
+	void setState(State state);
+
+	std::map<ButtonState, State> m_states;
+};
+
 #endif // QT_ICON_BUTTON_H