QPropertyAnimation for QGraphicsPolygonItem 不起作用

Question

我有一个类是从QGraphicsPolygonItem派生的。里面有一个负责动画的函数。函数如下所示:

void DrawBase::makeAnimation(){
        /* creating 2 states */
        QState* st1 = new QState();
        QState* st2 = new QState();
        st1->addTransition(this, SIGNAL(clicked()), st2);
        st2->addTransition(this, SIGNAL(clicked()), st1);
        /* adding states to state machine */
        _stateMachine.addState(st1);
        _stateMachine.addState(st2);
        _stateMachine.setInitialState(st1);
        QObject::connect(st1, SIGNAL(entered()), this, SLOT(animate1()));
        QObject::connect(st2, SIGNAL(entered()), this, SLOT(animate2()));
        /* starting machine */
        _stateMachine.start();
}

连接槽animate1()和animate2()如下:

void DrawBase::animate1()
{
    qDebug() << "Animation 1";
    animation = new QPropertyAnimation(this, "polygon");
    animation->setDuration(1000);
    animation->setStartValue(this->polygon());
    QTransform trans;
    trans=trans.scale(0.5,0.5);
    QPolygonF newPoly=trans.map(this->polygon());
    animation->setEndValue(newPoly);
    animation->setEasingCurve(QEasingCurve::OutBounce);
    animation->start();
}

Polygon属性没有被QPropertyAnimation看到，所以我在header中定义了这个属性:

Q_PROPERTY (QPolygonF polygon READ polygonNew WRITE setPolygonNew)PolygonNew和setPolygonNew调用QGraphicsPolygonItem类的polygon()和setPolygon()。

作为结果动画开始但不工作，我不确定它是否应该为多边形项目工作。在动画的开始polygonNew被调用了三次，setPolygonNew根本没有被调用。有人知道我该怎么做吗?

Answer 1

QPolygonF不支持QPropertyAimation的类型。您可以在这里看到支持的类型。

您必须提供自己的插值函数才能使其与QPolygonF一起工作。

下面是Qt文档提供的一个例子:

QVariant myColorInterpolator(const QColor &start, const QColor &end, qreal progress)
{
    ...
    return QColor(...);
}
...
qRegisterAnimationInterpolator<QColor>(myColorInterpolator);

下面是如何使用QPolygonF:

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
    Q_OBJECT
    Q_PROPERTY(QPolygonF polygon READ getPolygon WRITE setPolygon)
public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
    void setPolygon(QPolygonF polygon);
    QPolygonF getPolygon() const;
private:
    Ui::MainWindow *ui;
    QPolygonF poly;
};
#endif // MAINWINDOW_H

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QPropertyAnimation>
QVariant myPolygonInterpolator(const QPolygonF &start, const QPolygonF &end, qreal progress)
{
    if(progress < 1.0)
        return start;
    else
        return end;
}
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    qRegisterAnimationInterpolator<QPolygonF>(myPolygonInterpolator);
    poly << QPoint(10,0);
    QPropertyAnimation *animation = new QPropertyAnimation(this, "polygon");
    animation->setDuration(1000);
    QPolygonF start;
    start << QPoint(0, 0);
    animation->setStartValue(start);
    QPolygonF end;
    end << QPoint(100, 100);
    animation->setEndValue(end);
    animation->start(QAbstractAnimation::DeleteWhenStopped);
}
MainWindow::~MainWindow()
{
    delete ui;
}
void MainWindow::setPolygon(QPolygonF polygon)
{
    poly = polygon;
}
QPolygonF MainWindow::getPolygon() const
{
    return poly;
}