QGraphicsItemAnimation ¶

QGraphicsItemAnimation class provides simple animation support for QGraphicsItem . 更多 …

概要 ¶

函数 ¶

def clear ()
def horizontalScaleAt (step)
def horizontalShearAt (step)
def item ()
def matrixAt (step)
def posAt (step)
def posList ()
def rotationAt (step)
def rotationList ()
def scaleList ()
def setItem (item)
def setPosAt (step, pos)
def setRotationAt (step, angle)
def setScaleAt (step, sx, sy)
def setShearAt (step, sh, sv)
def setTimeLine (timeLine)
def setTranslationAt (step, dx, dy)
def shearList ()
def timeLine ()
def transformAt (step)
def translationList ()
def verticalScaleAt (step)
def verticalShearAt (step)
def xTranslationAt (step)
def yTranslationAt (step)

虚函数 ¶

def afterAnimationStep (step)
def beforeAnimationStep (step)

槽 ¶

def reset ()
def setStep (x)

详细描述 ¶

QGraphicsItemAnimation class animates a QGraphicsItem . You can schedule changes to the item’s transformation matrix at specified steps. The QGraphicsItemAnimation class has a current step value. When this value changes the transformations scheduled at that step are performed. The current step of the animation is set with the setStep() 函数。

QGraphicsItemAnimation will do a simple linear interpolation between the nearest adjacent scheduled changes to calculate the matrix. For instance, if you set the position of an item at values 0.0 and 1.0, the animation will show the item moving in a straight line between these positions. The same is true for scaling and rotation.

It is usual to use the class with a QTimeLine . The timeline’s valueChanged() signal is then connected to the setStep() slot. For example, you can set up an item for rotation by calling setRotationAt() for different step values. The animations timeline is set with the setTimeLine() 函数。

An example animation with a timeline follows:
QGraphicsItem *ball = new QGraphicsEllipseItem(0, 0, 20, 20);
QTimeLine *timer = new QTimeLine(5000);
timer->setFrameRange(0, 100);
QGraphicsItemAnimation *animation = new QGraphicsItemAnimation;
animation->setItem(ball);
animation->setTimeLine(timer);
for (int i = 0; i < 200; ++i)
    animation->setPosAt(i / 200.0, QPointF(i, i));
QGraphicsScene *scene = new QGraphicsScene;
scene->setSceneRect(0, 0, 250, 250);
scene->addItem(ball);
QGraphicsView *view = new QGraphicsView(scene);
view->show();
timer->start();
											
Note that steps lie between 0.0 and 1.0. It may be necessary to use setUpdateInterval() . The default update interval is 40 ms. A scheduled transformation cannot be removed when set, so scheduling several transformations of the same kind (e.g., rotations) at the same step is not recommended.

另请参阅

QTimeLine 图形视图框架

class QGraphicsItemAnimation ( [ parent=None ] ) ¶

param parent

QObject

Constructs an animation object with the given parent .

PySide2.QtWidgets.QGraphicsItemAnimation. afterAnimationStep ( step ) ¶

参数: step – qreal

This method is meant to be overridden in subclasses that need to execute additional code after a new step has taken place. The animation step is provided for use in cases where the action depends on its value.

PySide2.QtWidgets.QGraphicsItemAnimation. beforeAnimationStep ( step ) ¶

参数: step – qreal

This method is meant to be overridden by subclassed that needs to execute additional code before a new step takes place. The animation step is provided for use in cases where the action depends on its value.

PySide2.QtWidgets.QGraphicsItemAnimation. clear ( ) ¶: Clears the scheduled transformations used for the animation, but retains the item and timeline.

PySide2.QtWidgets.QGraphicsItemAnimation. horizontalScaleAt ( step ) ¶