QTimeLine¶
Synopsis¶
Functions¶
def
currentFrame
()def
currentTime
()def
currentValue
()def
curveShape
()def
direction
()def
duration
()def
easingCurve
()def
endFrame
()def
frameForTime
(msec)def
loopCount
()def
setCurveShape
(shape)def
setDirection
(direction)def
setDuration
(duration)def
setEasingCurve
(curve)def
setEndFrame
(frame)def
setFrameRange
(startFrame, endFrame)def
setLoopCount
(count)def
setStartFrame
(frame)def
setUpdateInterval
(interval)def
startFrame
()def
state
()def
updateInterval
()
Virtual functions¶
def
valueForTime
(msec)
Slots¶
def
resume
()def
setCurrentTime
(msec)def
setPaused
(paused)def
start
()def
stop
()def
toggleDirection
()
Detailed Description¶
It’s most commonly used to animate a GUI control by calling a slot periodically. You can construct a timeline by passing its duration in milliseconds to
QTimeLine
‘s constructor. The timeline’s duration describes for how long the animation will run. Then you set a suitable frame range by callingsetFrameRange()
. Finally connect theframeChanged()
signal to a suitable slot in the widget you wish to animate (for example,setValue()
inQProgressBar
). When you proceed to callingstart()
,QTimeLine
will enter Running state, and start emittingframeChanged()
at regular intervals, causing your widget’s connected property’s value to grow from the lower end to the upper and of your frame range, at a steady rate. You can specify the update interval by callingsetUpdateInterval()
. When done,QTimeLine
entersNotRunning
state, and emitsfinished()
.Example:
... progressBar = QProgressBar(self) progressBar.setRange(0, 100) # Construct a 1-second timeline with a frame range of 0 - 100 timeLine = QTimeLine(1000, self) timeLine.setFrameRange(0, 100) timeLine.frameChanged[int].connect(progressBar.setValue) # Clicking the push button will start the progress bar animation pushButton = QPushButton(QObject.tr("Start animation"), self) pushButton.clicked.connect(timeLine.start) ...By default the timeline runs once, from the beginning and towards the end, upon which you must call
start()
again to restart from the beginning. To make the timeline loop, you can callsetLoopCount()
, passing the number of times the timeline should run before finishing. The direction can also be changed, causing the timeline to run backward, by callingsetDirection()
. You can also pause and unpause the timeline while it’s running by callingsetPaused()
. For interactive control, thesetCurrentTime()
function is provided, which sets the time position of the time line directly. Although most useful inNotRunning
state, (e.g., connected to avalueChanged()
signal in aQSlider
,) this function can be called at any time.The frame interface is useful for standard widgets, but
QTimeLine
can be used to control any type of animation. The heart ofQTimeLine
lies in thevalueForTime()
function, which generates a value between 0 and 1 for a given time. This value is typically used to describe the steps of an animation, where 0 is the first step of an animation, and 1 is the last step. When running,QTimeLine
generates values between 0 and 1 by callingvalueForTime()
and emittingvalueChanged()
. By default,valueForTime()
applies an interpolation algorithm to generate these value. You can choose from a set of predefined timeline algorithms by callingsetCurveShape()
.Note that by default,
QTimeLine
uses the EaseInOut curve shape, which provides a value that grows slowly, then grows steadily, and finally grows slowly. For a custom timeline, you can reimplementvalueForTime()
, in which caseQTimeLine
‘scurveShape
property is ignored.See also
-
class
QTimeLine
([duration=1000[, parent=None]])¶ - param parent
- param duration
int
Constructs a timeline with a duration of
duration
milliseconds.parent
is passed toQObject
‘s constructor. The default duration is 1000 milliseconds.
-
PySide2.QtCore.QTimeLine.
State
¶ This enum describes the state of the timeline.
Constant
Description
QTimeLine.NotRunning
The timeline is not running. This is the initial state of
QTimeLine
, and the stateQTimeLine
reenters when finished. The current time, frame and value remain unchanged until eithersetCurrentTime()
is called, or the timeline is started by callingstart()
.QTimeLine.Paused
The timeline is paused (i.e., temporarily suspended). Calling
setPaused
(false) will resume timeline activity.QTimeLine.Running
The timeline is running. While control is in the event loop,
QTimeLine
will update its current time at regular intervals, emittingvalueChanged()
andframeChanged()
when appropriate.See also
state()
stateChanged()
-
PySide2.QtCore.QTimeLine.
Direction
¶ This enum describes the direction of the timeline when in
Running
state.Constant
Description
QTimeLine.Forward
The current time of the timeline increases with time (i.e., moves from 0 and towards the end / duration).
QTimeLine.Backward
The current time of the timeline decreases with time (i.e., moves from the end / duration and towards 0).
See also
-
PySide2.QtCore.QTimeLine.
CurveShape
¶ This enum describes the default shape of
QTimeLine
‘s value curve. The default, shape is . The curve defines the relation between the value and the timeline.Constant
Description
QTimeLine.EaseInCurve
The value starts growing slowly, then increases in speed.
QTimeLine.EaseOutCurve
The value starts growing steadily, then ends slowly.
QTimeLine.EaseInOutCurve
The value starts growing slowly, then runs steadily, then grows slowly again.
QTimeLine.LinearCurve
The value grows linearly (e.g., if the duration is 1000 ms, the value at time 500 ms is 0.5).
QTimeLine.SineCurve
The value grows sinusoidally.
QTimeLine.CosineCurve
The value grows cosinusoidally.
See also
-
PySide2.QtCore.QTimeLine.
currentFrame
()¶ - Return type
int
Returns the frame corresponding to the current time.
See also
-
PySide2.QtCore.QTimeLine.
currentTime
()¶ - Return type
int
See also
-
PySide2.QtCore.QTimeLine.
currentValue
()¶ - Return type
qreal
Returns the value corresponding to the current time.
See also
-
PySide2.QtCore.QTimeLine.
curveShape
()¶ - Return type
See also
-
PySide2.QtCore.QTimeLine.
direction
()¶ - Return type
See also
-
PySide2.QtCore.QTimeLine.
duration
()¶ - Return type
int
See also
-
PySide2.QtCore.QTimeLine.
easingCurve
()¶ - Return type
See also
-
PySide2.QtCore.QTimeLine.
endFrame
()¶ - Return type
int
Returns the end frame, which is the frame corresponding to the end of the timeline (i.e., the frame for which the current value is 1).
See also
-
PySide2.QtCore.QTimeLine.
frameForTime
(msec)¶ - Parameters
msec –
int
- Return type
int
Returns the frame corresponding to the time
msec
. This value is calculated using a linear interpolation of the start and end frame, based on the value returned byvalueForTime()
.See also
-
PySide2.QtCore.QTimeLine.
loopCount
()¶ - Return type
int
See also
-
PySide2.QtCore.QTimeLine.
resume
()¶ Resumes the timeline from the current time.
QTimeLine
will reenter Running state, and once it enters the event loop, it will update its current time, frame and value at regular intervals.In contrast to
start()
, this function does not restart the timeline before it resumes.See also
start()
updateInterval()
frameChanged()
valueChanged()
-
PySide2.QtCore.QTimeLine.
setCurrentTime
(msec)¶ - Parameters
msec –
int
See also
-
PySide2.QtCore.QTimeLine.
setCurveShape
(shape)¶ - Parameters
shape –
CurveShape
See also
-
PySide2.QtCore.QTimeLine.
setDuration
(duration)¶ - Parameters
duration –
int
See also
-
PySide2.QtCore.QTimeLine.
setEasingCurve
(curve)¶ - Parameters
curve –
QEasingCurve
See also
-
PySide2.QtCore.QTimeLine.
setEndFrame
(frame)¶ - Parameters
frame –
int
Sets the end frame, which is the frame corresponding to the end of the timeline (i.e., the frame for which the current value is 1), to
frame
.See also
-
PySide2.QtCore.QTimeLine.
setFrameRange
(startFrame, endFrame)¶ - Parameters
startFrame –
int
endFrame –
int
Sets the timeline’s frame counter to start at
startFrame
, and end andendFrame
. For each time value,QTimeLine
will find the corresponding frame when you callcurrentFrame()
orframeForTime()
by interpolating, using the return value ofvalueForTime()
.When in Running state,
QTimeLine
also emits theframeChanged()
signal when the frame changes.See also
-
PySide2.QtCore.QTimeLine.
setLoopCount
(count)¶ - Parameters
count –
int
See also
-
PySide2.QtCore.QTimeLine.
setPaused
(paused)¶ - Parameters
paused –
bool
If
paused
is true, the timeline is paused, causingQTimeLine
to enter Paused state. No updates will be signaled until eitherstart()
or (false) is called. Ifpaused
is false, the timeline is resumed and continues where it left.
-
PySide2.QtCore.QTimeLine.
setStartFrame
(frame)¶ - Parameters
frame –
int
Sets the start frame, which is the frame corresponding to the start of the timeline (i.e., the frame for which the current value is 0), to
frame
.See also
-
PySide2.QtCore.QTimeLine.
setUpdateInterval
(interval)¶ - Parameters
interval –
int
See also
-
PySide2.QtCore.QTimeLine.
start
()¶ Starts the timeline.
QTimeLine
will enter Running state, and once it enters the event loop, it will update its current time, frame and value at regular intervals. The default interval is 40 ms (i.e., 25 times per second). You can change the update interval by callingsetUpdateInterval()
.The timeline will start from position 0, or the end if going backward. If you want to resume a stopped timeline without restarting, you can call
resume()
instead.See also
resume()
updateInterval()
frameChanged()
valueChanged()
-
PySide2.QtCore.QTimeLine.
startFrame
()¶ - Return type
int
Returns the start frame, which is the frame corresponding to the start of the timeline (i.e., the frame for which the current value is 0).
See also
-
PySide2.QtCore.QTimeLine.
state
()¶ - Return type
Returns the state of the timeline.
See also
-
PySide2.QtCore.QTimeLine.
stop
()¶ Stops the timeline, causing
QTimeLine
to enterNotRunning
state.See also
-
PySide2.QtCore.QTimeLine.
toggleDirection
()¶ Toggles the direction of the timeline. If the direction was Forward, it becomes Backward, and vice verca.
See also
-
PySide2.QtCore.QTimeLine.
updateInterval
()¶ - Return type
int
See also
-
PySide2.QtCore.QTimeLine.
valueForTime
(msec)¶ - Parameters
msec –
int
- Return type
qreal
Returns the timeline value for the time
msec
. The returned value, which varies depending on the curve shape, is always between 0 and 1. Ifmsec
is 0, the default implementation always returns 0.Reimplement this function to provide a custom curve shape for your timeline.
See also
CurveShape
frameForTime()
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