Detailed Description
The QWheelEvent class contains parameters that describe a wheel event.
Wheel events are sent to the widget under the mouse, and if that widget
does not handle the event they are sent to the focus widget. The rotation
distance is provided by delta(). The functions pos() and globalPos() return
the mouse pointer location at the time of the event.
A wheel event contains a special accept flag that indicates
whether the receiver wants the event. You should call
QWheelEvent::accept() if you handle the wheel event; otherwise it
will be sent to the parent widget.
The QWidget::setEnable() function can be used to enable or disable
mouse and keyboard events for a widget.
The event handler QWidget::wheelEvent() receives wheel events.
See also QMouseEvent, QWidget::grabMouse(), and Event Classes.
Member Function Documentation
QWheelEvent::QWheelEvent ( const QPoint & pos, int delta, int state, Orientation orient = Vertical )
Constructs a wheel event object.
The globalPos() is initialized to QCursor::pos(), i.e. pos,
which is usually (but not always) right. Use the other constructor
if you need to specify the global position explicitly. delta
contains the rotation distance, state holds the keyboard
modifier flags at the time of the event and orient holds the
wheel's orientation.
See also pos(), delta(), and state().
QWheelEvent::QWheelEvent ( const QPoint & pos, const QPoint & globalPos, int delta, int state, Orientation orient = Vertical )
Constructs a wheel event object. The position when the event
occurred is given in pos and globalPos. delta contains
the rotation distance, state holds the keyboard modifier flags
at the time of the event and orient holds the wheel's
orientation.
See also pos(), globalPos(), delta(), and state().
void QWheelEvent::accept ()
Sets the accept flag of the wheel event object.
Setting the accept parameter indicates that the receiver of the
event wants the wheel event. Unwanted wheel events are sent to the
parent widget.
The accept flag is set by default.
See also ignore().
int QWheelEvent::delta () const
Returns the distance that the wheel is rotated expressed in
multiples or divisions of WHEEL_DELTA, which is currently set
at 120. A positive value indicates that the wheel was rotated
forwards away from the user; a negative value indicates that the
wheel was rotated backwards toward the user.
The WHEEL_DELTA constant was set to 120 by the wheel mouse
vendors to allow building finer-resolution wheels in the future,
including perhaps a freely rotating wheel with no notches. The
expectation is that such a device would send more messages per
rotation but with a smaller value in each message.
const QPoint & QWheelEvent::globalPos () const
Returns the global position of the mouse pointer at the time of the event. This is important on asynchronous window systems
such as X11; whenever you move your widgets around in response to
mouse events, globalPos() can differ a lot from the current
pointer position QCursor::pos().
See also globalX() and globalY().
int QWheelEvent::globalX () const
Returns the global x-position of the mouse pointer at the time of
the event.
See also globalY() and globalPos().
int QWheelEvent::globalY () const
Returns the global y-position of the mouse pointer at the time of
the event.
See also globalX() and globalPos().
void QWheelEvent::ignore ()
Clears the accept flag parameter of the wheel event object.
Clearing the accept parameter indicates that the event receiver
does not want the wheel event. Unwanted wheel events are sent to
the parent widget. The accept flag is set by default.
See also accept().
bool QWheelEvent::isAccepted () const
Returns TRUE if the receiver of the event handles the wheel event;
otherwise returns FALSE.
Orientation QWheelEvent::orientation () const
Returns the wheel's orientation.
const QPoint & QWheelEvent::pos () const
Returns the position of the mouse pointer, relative to the widget
that received the event.
If you move your widgets around in response to mouse
events, use globalPos() instead of this function.
See also x(), y(), and globalPos().
ButtonState QWheelEvent::state () const
Returns the keyboard modifier flags of the event.
The returned value is ShiftButton, ControlButton, and AltButton OR'ed together.
int QWheelEvent::x () const
Returns the x-position of the mouse pointer, relative to the
widget that received the event.
See also y() and pos().
int QWheelEvent::y () const
Returns the y-position of the mouse pointer, relative to the
widget that received the event.
See also x() and pos().
This file is part of the Qt toolkit.
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