QScroller#
The QScroller class enables kinetic scrolling for any scrolling widget or graphics item. More…
Synopsis#
Properties#
scrollerProperties- Scroller properties of this scroller. The properties are used by the QScroller to determine its scrolling behaviorstate- The state of the scroller
Functions#
def
finalPosition()def
handleInput(input, position[, timestamp=0])def
pixelPerMeter()def
scrollerProperties()def
setSnapPositionsX(positions)def
setSnapPositionsX(first, interval)def
setSnapPositionsY(positions)def
setSnapPositionsY(first, interval)def
state()def
stop()def
target()def
velocity()
Slots#
def
ensureVisible(rect, xmargin, ymargin)def
ensureVisible(rect, xmargin, ymargin, scrollTime)def
resendPrepareEvent()def
scrollTo(pos)def
scrollTo(pos, scrollTime)def
setScrollerProperties(prop)
Signals#
def
scrollerPropertiesChanged(arg__1)def
stateChanged(newstate)
Static functions#
def
activeScrollers()def
grabGesture(target[, gestureType=QScroller.ScrollerGestureType.TouchGesture])def
grabbedGesture(target)def
hasScroller(target)def
scroller(target)def
scroller(target)def
ungrabGesture(target)
Note
This documentation may contain snippets that were automatically translated from C++ to Python. We always welcome contributions to the snippet translation. If you see an issue with the translation, you can also let us know by creating a ticket on https:/bugreports.qt.io/projects/PYSIDE
Detailed Description#
Warning
This section contains snippets that were automatically translated from C++ to Python and may contain errors.
With kinetic scrolling, the user can push the widget in a given direction and it will continue to scroll in this direction until it is stopped either by the user or by friction. Aspects of inertia, friction and other physical concepts can be changed in order to fine-tune an intuitive user experience.
The QScroller object is the object that stores the current position and scrolling speed and takes care of updates. QScroller can be triggered by a flick gesture
w = ... QScroller.grabGesture(w, QScroller.LeftMouseButtonGesture)
or directly like this:
w = ... scroller = QScroller.scroller(w) scroller.scrollTo(QPointF(100, 100))
The scrolled QObjects receive a QScrollPrepareEvent whenever the scroller needs to update its geometry information and a QScrollEvent whenever the content of the object should actually be scrolled.
The scroller uses the global QAbstractAnimation timer to generate its QScrollEvents. This can be changed with FrameRate on a per- QScroller basis.
The Dir View Example shows one way to use a QScroller with a QTreeView . An example in the scroller examples directory also demonstrates QScroller .
Even though this kinetic scroller has a large number of settings available via QScrollerProperties , we recommend that you leave them all at their default, platform optimized values. Before changing them you can experiment with the plot example in the scroller examples directory.
See also
QScrollEventQScrollPrepareEventQScrollerProperties
- class PySide6.QtWidgets.QScroller#
Note
Properties can be used directly when from __feature__ import true_property is used or via accessor functions otherwise.
- property PᅟySide6.QtWidgets.QScroller.scrollerProperties: PySide6.QtWidgets.QScrollerProperties#
This property holds The scroller properties of this scroller. The properties are used by the QScroller to determine its scrolling behavior..
- Access functions:
setScrollerProperties(prop)Signal
scrollerPropertiesChanged(arg__1)
This property holds the state of the scroller.
See also
State
- Access functions:
state()Signal
stateChanged(newstate)
- PySide6.QtWidgets.QScroller.State#
This enum contains the different QScroller states.
Constant
Description
QScroller.Inactive
The scroller is not scrolling and nothing is pressed.
QScroller.Pressed
A touch event was received or the mouse button was pressed but the scroll area is currently not dragged.
QScroller.Dragging
The scroll area is currently following the touch point or mouse.
QScroller.Scrolling
The scroll area is moving on it’s own.
- PySide6.QtWidgets.QScroller.ScrollerGestureType#
This enum contains the different gesture types that are supported by the QScroller gesture recognizer.
Constant
Description
QScroller.TouchGesture
The gesture recognizer will only trigger on touch events. Specifically it will react on single touch points when using a touch screen and dual touch points when using a touchpad.
QScroller.LeftMouseButtonGesture
The gesture recognizer will only trigger on left mouse button events.
QScroller.MiddleMouseButtonGesture
The gesture recognizer will only trigger on middle mouse button events.
QScroller.RightMouseButtonGesture
The gesture recognizer will only trigger on right mouse button events.
- PySide6.QtWidgets.QScroller.Input#
This enum contains an input device agnostic view of input events that are relevant for QScroller .
Constant
Description
QScroller.InputPress
The user pressed the input device (e.g.
MouseButtonPress,GraphicsSceneMousePress,TouchBegin)QScroller.InputMove
The user moved the input device (e.g.
MouseMove,GraphicsSceneMouseMove,TouchUpdate)QScroller.InputRelease
The user released the input device (e.g.
MouseButtonRelease,GraphicsSceneMouseRelease,TouchEnd)
- static PySide6.QtWidgets.QScroller.activeScrollers()#
- Return type:
Returns an application wide list of currently active QScroller objects. Active QScroller objects are in a state() that is not Inactive . This function is useful when writing your own gesture recognizer.
- PySide6.QtWidgets.QScroller.ensureVisible(rect, xmargin, ymargin)#
- Parameters:
rect –
PySide6.QtCore.QRectFxmargin – float
ymargin – float
Starts scrolling so that the rectangle rect is visible inside the viewport with additional margins specified in pixels by xmargin and ymargin around the rect.
In cases where it is not possible to fit the rect plus margins inside the viewport the contents are scrolled so that as much as possible is visible from rect.
The scrolling speed is calculated so that the given position is reached after a platform-defined time span.
This function performs the actual scrolling by calling scrollTo() .
See also
- PySide6.QtWidgets.QScroller.ensureVisible(rect, xmargin, ymargin, scrollTime)
- Parameters:
rect –
PySide6.QtCore.QRectFxmargin – float
ymargin – float
scrollTime – int
This is an overloaded function.
This version will reach its destination position in scrollTime milliseconds.
- PySide6.QtWidgets.QScroller.finalPosition()#
- Return type:
Returns the estimated final position for the current scroll movement. Returns the current position if the scroller state is not Scrolling. The result is undefined when the scroller state is Inactive.
The target position is in pixel.
See also
- static PySide6.QtWidgets.QScroller.grabGesture(target[, gestureType=QScroller.ScrollerGestureType.TouchGesture])#
- Parameters:
target –
PySide6.QtCore.QObjectgestureType –
ScrollerGestureType
- Return type:
Registers a custom scroll gesture recognizer, grabs it for the target and returns the resulting gesture type. If scrollGestureType is set to TouchGesture the gesture triggers on touch events. If it is set to one of LeftMouseButtonGesture , RightMouseButtonGesture or MiddleMouseButtonGesture it triggers on mouse events of the corresponding button.
Only one scroll gesture can be active on a single object at the same time. If you call this function twice on the same object, it will ungrab the existing gesture before grabbing the new one.
Note
To avoid unwanted side-effects, mouse events are consumed while the gesture is triggered. Since the initial mouse press event is not consumed, the gesture sends a fake mouse release event at the global position (INT_MIN, INT_MIN). This ensures that internal states of the widget that received the original mouse press are consistent.
See also
- static PySide6.QtWidgets.QScroller.grabbedGesture(target)#
- Parameters:
target –
PySide6.QtCore.QObject- Return type:
Returns the gesture type currently grabbed for the target or 0 if no gesture is grabbed.
See also
- PySide6.QtWidgets.QScroller.handleInput(input, position[, timestamp=0])#
- Parameters:
input –
Inputposition –
PySide6.QtCore.QPointFtimestamp – int
- Return type:
bool
This function is used by gesture recognizers to inform the scroller about a new input event. The scroller changes its internal state() according to the input event and its attached scroller properties. The scroller doesn’t distinguish between the kind of input device the event came from. Therefore the event needs to be split into the input type, a position and a milli-second timestamp. The position needs to be in the target’s coordinate system.
The return value is true if the event should be consumed by the calling filter or false if the event should be forwarded to the control.
Note
Using grabGesture() should be sufficient for most use cases.
- static PySide6.QtWidgets.QScroller.hasScroller(target)#
- Parameters:
target –
PySide6.QtCore.QObject- Return type:
bool
Returns true if a QScroller object was already created for target; false otherwise.
See also
- PySide6.QtWidgets.QScroller.pixelPerMeter()#
- Return type:
Returns the pixel per meter metric for the scrolled widget.
The value is reported for both the x and y axis separately by using a QPointF .
Note
Please note that this value should be physically correct. The actual DPI settings that Qt returns for the display may be reported wrongly on purpose by the underlying windowing system, for example on macOS.
- PySide6.QtWidgets.QScroller.resendPrepareEvent()#
This function resends the QScrollPrepareEvent . Calling resendPrepareEvent triggers a QScrollPrepareEvent from the scroller. This allows the receiver to re-set content position and content size while scrolling. Calling this function while in the Inactive state is useless as the prepare event is sent again before scrolling starts.
- PySide6.QtWidgets.QScroller.scrollTo(pos)#
- Parameters:
pos –
PySide6.QtCore.QPointF
Starts scrolling the widget so that point pos is at the top-left position in the viewport.
The behaviour when scrolling outside the valid scroll area is undefined. In this case the scroller might or might not overshoot.
The scrolling speed will be calculated so that the given position will be reached after a platform-defined time span.
pos is given in viewport coordinates.
See also
- PySide6.QtWidgets.QScroller.scrollTo(pos, scrollTime)
- Parameters:
pos –
PySide6.QtCore.QPointFscrollTime – int
This is an overloaded function.
This version will reach its destination position in scrollTime milliseconds.
- static PySide6.QtWidgets.QScroller.scroller(target)#
- Parameters:
target –
PySide6.QtCore.QObject- Return type:
This is an overloaded function.
This is the const version of scroller() .
- static PySide6.QtWidgets.QScroller.scroller(target)
- Parameters:
target –
PySide6.QtCore.QObject- Return type:
Returns the scroller for the given target. As long as the object exists this function will always return the same QScroller instance. If no QScroller exists for the target, one will implicitly be created. At no point more than one QScroller will be active on an object.
See also
- PySide6.QtWidgets.QScroller.scrollerProperties()#
- Return type:
See also
Getter of property scrollerProperties .
- PySide6.QtWidgets.QScroller.scrollerPropertiesChanged(arg__1)#
- Parameters:
QScroller emits this signal whenever its scroller properties change. newProperties are the new scroller properties.
See also
Notification signal of property scrollerProperties .
- PySide6.QtWidgets.QScroller.setScrollerProperties(prop)#
- Parameters:
See also
Setter of property scrollerProperties .
- PySide6.QtWidgets.QScroller.setSnapPositionsX(positions)#
- Parameters:
positions –
Set the snap positions for the horizontal axis to a list of positions. This overwrites all previously set snap positions and also a previously set snapping interval. Snapping can be deactivated by setting an empty list of positions.
- PySide6.QtWidgets.QScroller.setSnapPositionsX(first, interval)
- Parameters:
first – float
interval – float
Set the snap positions for the horizontal axis to regular spaced intervals. The first snap position is at first. The next at first + interval. This can be used to implement a list header. This overwrites all previously set snap positions and also a previously set snapping interval. Snapping can be deactivated by setting an interval of 0.0
- PySide6.QtWidgets.QScroller.setSnapPositionsY(positions)#
- Parameters:
positions –
Set the snap positions for the vertical axis to a list of positions. This overwrites all previously set snap positions and also a previously set snapping interval. Snapping can be deactivated by setting an empty list of positions.
- PySide6.QtWidgets.QScroller.setSnapPositionsY(first, interval)
- Parameters:
first – float
interval – float
Set the snap positions for the vertical axis to regular spaced intervals. The first snap position is at first. The next at first + interval. This overwrites all previously set snap positions and also a previously set snapping interval. Snapping can be deactivated by setting an interval of 0.0
Getter of property state .
QScroller emits this signal whenever the state changes. newState is the new State.
See also
Notification signal of property state .
- PySide6.QtWidgets.QScroller.stop()#
Stops the scroller and resets its state back to Inactive.
- PySide6.QtWidgets.QScroller.target()#
- Return type:
Returns the target object of this scroller.
See also
- static PySide6.QtWidgets.QScroller.ungrabGesture(target)#
- Parameters:
target –
PySide6.QtCore.QObject
Ungrabs the gesture for the target. Does nothing if no gesture is grabbed.
See also
- PySide6.QtWidgets.QScroller.velocity()#
- Return type:
Returns the current scrolling velocity in meter per second when the state is Scrolling or Dragging. Returns a zero velocity otherwise.
The velocity is reported for both the x and y axis separately by using a QPointF .
See also