Qt Animation Framework

With the advent of Qt 4.6, the implementation of animation in the project has been simplified to a minimum.

In the event that animation of component properties is needed, Qt 4.6 suggests using the QPropertyAnimation class . Here is an example widget resize animation:

1. #include
2. #include
3. #include
4.  
5. class MyWidget : public QWidget {
6. public:
7.   MyWidget(QObject* parent = 0);
8.   // MyWidget fields and methods
9. public slots:
10.   void startAnimation();
11. private:
12.   QPropertyAnimation* _propertyAnimation;
13. };

* This source code was highlighted with Source Code Highlighter.

1. MyWidget::MyWidget(QObject *parent) : QWidget(parent) {
2.   // Widget initialization
3.   _propertyAnimation = new QPropertyAnimation(this,"geometry");
4.   _propertyAnimation->setDuration(1000);
5.   _propertyAnimation->setEasingCurve(QEasingCurve::OutCubic);
6. }
7.  
8. void MyWidget::startAnimation() {
9.   QRectF firstPosition;
10.   QRectF endPosition;
11.   // Initializing first and end values
12.   _propertyAnimation->setFirstValue(firstPosition);
13.   _propertyAnimation->setEndValue(endPosition);
14.   _propertyAnimation->start();
15. }

* This source code was highlighted with Source Code Highlighter.

Using the setDuration (int) method, the duration of the animation is set, and using the setEasingCurve (const QEasingCurve &) method, the curve of the value changes over time. In this example, the OutQuad curve is selected.


Actually, 6 lines and all.

To animate a non-property value, you can inherit from QVariantAnimation and override the void updateCurrentValue (const QVariant &) method . In this method, it is necessary to describe the logic of what should happen when the value changes.

QVariantAnimation supports the following types: Int, Double, Float, QLine, QLineF, QPoint, QSize, QSizeF, QRect, QRectF. If the type of the value being changed does not belong to any of the above, you need to redefine the interpolation method virtual QVariant interpolated (const QVariant & from, const QVariant & to, qreal progress) const

Here is an example of what happened: