QWheelEvent¶
The
QWheelEvent
class contains parameters that describe a wheel event. More…
Synopsis¶
Functions¶
def
angleDelta
()def
buttons
()def
delta
()def
globalPos
()def
globalPosF
()def
globalX
()def
globalY
()def
inverted
()def
orientation
()def
phase
()def
pixelDelta
()def
pos
()def
posF
()def
source
()def
x
()def
y
()
Detailed Description¶
Wheel events are sent to the widget under the mouse cursor, but if that widget does not handle the event they are sent to the focus widget. Wheel events are generated for both mouse wheels and trackpad scroll gestures. There are two ways to read the wheel event delta:
angleDelta()
returns the delta in wheel degrees. This value is always provided.pixelDelta()
returns the delta in screen pixels and is available on platforms that have high-resolution trackpads, such as macOS . If that is the case,source()
will returnMouseEventSynthesizedBySystem
.The functions
pos()
andglobalPos()
return the mouse cursor’s 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
ignore()
if you do not handle the wheel event; this ensures that it will be sent to the parent widget.The
setEnabled()
function can be used to enable or disable mouse and keyboard events for a widget.The event handler
wheelEvent()
receives wheel events.See also
QMouseEvent
grabMouse()
-
class
QWheelEvent
(pos, globalPos, pixelDelta, angleDelta, buttons, modifiers, phase, inverted[, source=Qt.MouseEventNotSynthesized])¶ QWheelEvent(pos, globalPos, pixelDelta, angleDelta, qt4Delta, qt4Orientation, buttons, modifiers)
QWheelEvent(pos, globalPos, pixelDelta, angleDelta, qt4Delta, qt4Orientation, buttons, modifiers, phase)
QWheelEvent(pos, globalPos, pixelDelta, angleDelta, qt4Delta, qt4Orientation, buttons, modifiers, phase, source)
QWheelEvent(pos, globalPos, pixelDelta, angleDelta, qt4Delta, qt4Orientation, buttons, modifiers, phase, source, inverted)
QWheelEvent(pos, globalPos, delta, buttons, modifiers[, orient=Qt.Vertical])
QWheelEvent(pos, delta, buttons, modifiers[, orient=Qt.Vertical])
- param source
MouseEventSource
- param globalPos
QPointF
- param inverted
bool
- param modifiers
KeyboardModifiers
- param angleDelta
QPoint
- param buttons
MouseButtons
- param pos
QPointF
- param pixelDelta
QPoint
- param phase
ScrollPhase
- param delta
int
- param orient
Orientation
- param qt4Delta
int
- param qt4Orientation
Orientation
Constructs a wheel event object.
The
pos
provides the location of the mouse cursor within the window. The position in global coordinates is specified byglobalPos
.pixelDelta
contains the scrolling distance in pixels on screen, whileangleDelta
contains the wheel rotation distance.pixelDelta
is optional and can be null.The mouse and keyboard states at the time of the event are specified by
buttons
andmodifiers
.The scrolling phase of the event is specified by
phase
.If the wheel event comes from a physical mouse wheel,
source
is set toMouseEventNotSynthesized
. If it comes from a gesture detected by the operating system, or from a non-mouse hardware device, such thatpixelDelta
is directly related to finger movement,source
is set toMouseEventSynthesizedBySystem
. If it comes from Qt, source would be set toMouseEventSynthesizedByQt
.If the system is configured to invert the delta values delivered with the event (such as natural scrolling of the touchpad on macOS ),
inverted
should betrue
. Otherwise,inverted
isfalse
See also
posF()
globalPosF()
angleDelta()
pixelDelta()
phase()
Constructs a wheel event object.
The
pos
provides the location of the mouse cursor within the window. The position in global coordinates is specified byglobalPos
.pixelDelta
contains the scrolling distance in pixels on screen, whileangleDelta
contains the wheel rotation distance.pixelDelta
is optional and can be null.The mouse and keyboard states at the time of the event are specified by
buttons
andmodifiers
.For backwards compatibility, the event can also hold monodirectional wheel event data:
qt4Delta
specifies the rotation, andqt4Orientation
the direction.The
phase()
is initialized toScrollUpdate
. Use the other constructor to specify the phase explicitly.See also
posF()
globalPosF()
angleDelta()
pixelDelta()
Constructs a wheel event object.
The
pos
provides the location of the mouse cursor within the window. The position in global coordinates is specified byglobalPos
.pixelDelta
contains the scrolling distance in pixels on screen, whileangleDelta
contains the wheel rotation distance.pixelDelta
is optional and can be null.The mouse and keyboard states at the time of the event are specified by
buttons
andmodifiers
.For backwards compatibility, the event can also hold monodirectional wheel event data:
qt4Delta
specifies the rotation, andqt4Orientation
the direction.The scrolling phase of the event is specified by
phase
.If the wheel event comes from a physical mouse wheel,
source
is set toMouseEventNotSynthesized
. If it comes from a gesture detected by the operating system, or from a non-mouse hardware device, such thatpixelDelta
is directly related to finger movement,source
is set toMouseEventSynthesizedBySystem
. If it comes from Qt, source would be set toMouseEventSynthesizedByQt
.See also
posF()
globalPosF()
angleDelta()
pixelDelta()
phase()
Constructs a wheel event object.
The
pos
provides the location of the mouse cursor within the window. The position in global coordinates is specified byglobalPos
.pixelDelta
contains the scrolling distance in pixels on screen, whileangleDelta
contains the wheel rotation distance.pixelDelta
is optional and can be null.The mouse and keyboard states at the time of the event are specified by
buttons
andmodifiers
.For backwards compatibility, the event can also hold monodirectional wheel event data:
qt4Delta
specifies the rotation, andqt4Orientation
the direction.The scrolling phase of the event is specified by
phase
.If the wheel event comes from a physical mouse wheel,
source
is set toMouseEventNotSynthesized
. If it comes from a gesture detected by the operating system, or from a non-mouse hardware device, such thatpixelDelta
is directly related to finger movement,source
is set toMouseEventSynthesizedBySystem
. If it comes from Qt, source would be set toMouseEventSynthesizedByQt
.If the system is configured to invert the delta values delivered with the event (such as natural scrolling of the touchpad on OS X),
inverted
should betrue
. Otherwise,inverted
isfalse
See also
posF()
globalPosF()
angleDelta()
pixelDelta()
phase()
Constructs a wheel event object.
Use the constructor taking angleDelta and pixelDelta QPoints instead.
The
pos
provides the location of the mouse cursor within the widget. The position in global coordinates is specified byglobalPos
.delta
contains the rotation distance,modifiers
holds the keyboard modifier flags at the time of the event, andorient
holds the wheel’s orientation.See also
pos()
pixelDelta()
angleDelta()
Constructs a wheel event object.
Use the constructor taking angleDelta and pixelDelta QPoints instead.
The position,
pos
, is the location of the mouse cursor within the widget. TheglobalPos()
is initialized topos()
which is usually, but not always, correct. Use the other constructor if you need to specify the global position explicitly.The
buttons
describe the state of the mouse buttons at the time of the event,delta
contains the rotation distance,modifiers
holds the keyboard modifier flags at the time of the event, andorient
holds the wheel’s orientation.See also
pos()
pixelDelta()
angleDelta()
-
PySide2.QtGui.QWheelEvent.
pixelD
¶
-
PySide2.QtGui.QWheelEvent.
angleD
¶
-
PySide2.QtGui.QWheelEvent.
qt4D
¶
-
PySide2.QtGui.QWheelEvent.
qt4O
¶
-
PySide2.QtGui.QWheelEvent.
_unused_
¶
-
PySide2.QtGui.QWheelEvent.
src
¶
-
PySide2.QtGui.QWheelEvent.
invertedScrolling
¶
-
PySide2.QtGui.QWheelEvent.
ph
¶
-
PySide2.QtGui.QWheelEvent.
reserved
¶
-
PySide2.QtGui.QWheelEvent.
angleDelta
()¶ - Return type
QPoint
Returns the distance that the wheel is rotated, in eighths of a degree. 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.
Most mouse types work in steps of 15 degrees, in which case the delta value is a multiple of 120; i.e., 120 units * 1/8 = 15 degrees.
However, some mice have finer-resolution wheels and send delta values that are less than 120 units (less than 15 degrees). To support this possibility, you can either cumulatively add the delta values from events until the value of 120 is reached, then scroll the widget, or you can partially scroll the widget in response to each wheel event.
Example:
def wheelEvent(self, event): numDegrees = event.delta() / 8 numSteps = numDegrees / 15 if event->orientation() == Qt.Horizontal: scrollHorizontally(numSteps) else: scrollVertically(numSteps) event.accept()
Note
On platforms that support scrolling
phases
, the delta may be null when:scrolling is about to begin, but the distance did not yet change (
ScrollBegin
),or scrolling has ended and the distance did not change anymore (
ScrollEnd
).
- Return type
MouseButtons
Returns the mouse state when the event occurred.
-
PySide2.QtGui.QWheelEvent.
delta
()¶ - Return type
int
This function has been deprecated, use
pixelDelta()
orangleDelta()
instead.
-
PySide2.QtGui.QWheelEvent.
globalPos
()¶ - Return type
QPoint
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, can differ a lot from the current cursor position returned by
pos()
.See also
globalX()
globalY()
-
PySide2.QtGui.QWheelEvent.
globalPosF
()¶ - Return type
QPointF
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, can differ a lot from the current cursor position returned by
pos()
.See also
posF()
-
PySide2.QtGui.QWheelEvent.
globalX
()¶ - Return type
int
Returns the global x position of the mouse cursor at the time of the event.
See also
globalY()
globalPos()
-
PySide2.QtGui.QWheelEvent.
globalY
()¶ - Return type
int
Returns the global y position of the mouse cursor at the time of the event.
See also
globalX()
globalPos()
-
PySide2.QtGui.QWheelEvent.
inverted
()¶ - Return type
bool
Returns whether the delta values delivered with the event are inverted.
Normally, a vertical wheel will produce a
QWheelEvent
with positive delta values if the top of the wheel is rotating away from the hand operating it. Similarly, a horizontal wheel movement will produce aQWheelEvent
with positive delta values if the top of the wheel is moved to the left.However, on some platforms this is configurable, so that the same operations described above will produce negative delta values (but with the same magnitude). With the inverted property a wheel event consumer can choose to always follow the direction of the wheel, regardless of the system settings, but only for specific widgets. (One such use case could be that the user is rotating the wheel in the same direction as a visual Tumbler rotates. Another usecase is to make a slider handle follow the direction of movement of fingers on a touchpad regardless of system configuration.)
Note
Many platforms provide no such information. On such platforms inverted always returns false.
-
PySide2.QtGui.QWheelEvent.
orientation
()¶ - Return type
Orientation
Returns the wheel’s orientation.
Use
angleDelta()
instead.
-
PySide2.QtGui.QWheelEvent.
phase
()¶ - Return type
ScrollPhase
Returns the scrolling phase of this wheel event.
Note
The
ScrollBegin
andScrollEnd
phases are currently supported only on macOS .
-
PySide2.QtGui.QWheelEvent.
pixelDelta
()¶ - Return type
QPoint
Returns the scrolling distance in pixels on screen. This value is provided on platforms that support high-resolution pixel-based delta values, such as macOS . The value should be used directly to scroll content on screen.
Example:
def wheelEvent(self, event): numDegrees = event.delta() / 8 numSteps = numDegrees / 15 if event->orientation() == Qt.Horizontal: scrollHorizontally(numSteps) else: scrollVertically(numSteps) event.accept()
Note
On platforms that support scrolling
phases
, the delta may be null when:scrolling is about to begin, but the distance did not yet change (
ScrollBegin
),or scrolling has ended and the distance did not change anymore (
ScrollEnd
).
Note
On X11 this value is driver specific and unreliable, use
angleDelta()
instead
-
PySide2.QtGui.QWheelEvent.
pos
()¶ - Return type
QPoint
Returns the position of the mouse cursor 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()
globalPos()
-
PySide2.QtGui.QWheelEvent.
posF
()¶ - Return type
QPointF
Returns the position of the mouse cursor relative to the widget that received the event.
If you move your widgets around in response to mouse events, use
globalPosF()
instead of this function.See also
globalPosF()
-
PySide2.QtGui.QWheelEvent.
source
()¶ - Return type
MouseEventSource
Returns information about the wheel event source.
The source can be used to distinguish between events that come from a mouse with a physical wheel and events that are generated by some other means, such as a flick gesture on a touchpad.
Note
Many platforms provide no such information. On such platforms
MouseEventNotSynthesized
is returned always.See also
MouseEventSource
-
PySide2.QtGui.QWheelEvent.
x
()¶ - Return type
int
Returns the x position of the mouse cursor, relative to the widget that received the event.
See also
y()
pos()
-
PySide2.QtGui.QWheelEvent.
y
()¶ - Return type
int
Returns the y position of the mouse cursor, relative to the widget that received the event.
See also
x()
pos()
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