text: The QToolButton class provides a quick-access button to commands or options, usually used inside a QToolBar. More...
  #include <QToolButton>
  Inherits QAbstractButton.
  The QToolButton class provides a quick-access button to commands or options, usually used inside a QToolBar.
  A tool button is a special button that provides quick-access to specific commands or options. As opposed to a normal command button, a tool button usually doesn't show a text label, but shows an icon instead.
  Tool buttons are normally created when new QAction instances are created with QToolBar::addAction() or existing actions are added to a toolbar with QToolBar::addAction(). It is also possible to construct tool buttons in the same way as any other widget, and arrange them alongside other widgets in layouts.
  One classic use of a tool button is to select tools; for example, the "pen" tool in a drawing program. This would be implemented by using a QToolButton as a toggle button (see setToggleButton()).
  QToolButton supports auto-raising. In auto-raise mode, the button draws a 3D frame only when the mouse points at it. The feature is automatically turned on when a button is used inside a QToolBar. Change it with setAutoRaise().
  A tool button's icon is set as QIcon. This makes it possible to specify different pixmaps for the disabled and active state. The disabled pixmap is used when the button's functionality is not available. The active pixmap is displayed when the button is auto-raised because the mouse pointer is hovering over it.
  The button's look and dimension is adjustable with setToolButtonStyle() and setIconSize(). When used inside a QToolBar in a QMainWindow, the button automatically adjusts to QMainWindow's settings (see QMainWindow::setToolButtonStyle() and QMainWindow::setIconSize()). Instead of an icon, a tool button can also display an arrow symbol, specified with arrowType.
  A tool button can offer additional choices in a popup menu. The popup menu can be set using setMenu(). Use setPopupMode() to configure the different modes available for tool buttons with a menu set. The default mode is DelayedPopupMode which is sometimes used with the "Back" button in a web browser. After pressing and holding the button down for a while, a menu pops up showing a list of possible pages to jump to. The.
  To have the style of toolbuttons follow the system settings (as available in GNOME and KDE desktop environments), set this property to Qt::ToolButtonFollowStyle.
  QToolButton automatically connects this slot to the relevant signal in the QMainWindow in which is resides.
  Access functions:
  Constructs an empty tool button with parent parent.
  Destroys the object and frees any allocated resources..