Jumping/stuttering during animation QPainter

[ghm]

Hi.

I have a small testproject, where I have painted a roundedrect box, that I want to animate. My problem is that I can't get the animation to run smoothly.

The painted box is animated with a duration of 1000ms, and "stutters" frequently while moving across the dialog.

This is the code for the roundedrect box:



#include "groupbox.h"
#include <QPainter>
#include <QDebug>

GroupBox::GroupBox(QWidget *parent)
: QWidget(parent)
{
}

GroupBox::~GroupBox()
{
}

void GroupBox::paintEvent(QPaintEvent *)
{
QPainter painter;
painter.begin(this);
painter.setRenderHint(QPainter::Antialiasing);
painter.setPen(QPen(QBrush(qRgb(128,128,128)), 5));
painter.setBrush(QBrush(qRgb(46,46,46)));
painter.drawRoundedRect(QRect(35,35,250,150),25,25 );

painter.end();

}


And here is the code for the animation part:


#include "dialog.h"
#include <QDebug>

Dialog::Dialog(QWidget *parent)
: QDialog(parent)
{
resize(1400,600);

m_group = new GroupBox(this);
m_group->resize(310,200);
m_group->show();

m_animation = new QPropertyAnimation(m_group, "pos", this);
m_animation->setDuration(1000);
m_animation->setEasingCurve(QEasingCurve::Linear);

// Continuous animation from startup
m_group->move(10, 0);


animateMove();
connect(m_animation, SIGNAL(finished()), this, SLOT(animateMove()));
}

Dialog::~Dialog()
{
}


void Dialog::animateMove()
{
if (m_group->pos().x() != 10)
{
m_animation->setStartValue(m_group->pos());
m_animation->setEndValue(QPointF(10.0,0.0));
m_animation->start();
}
else
{
m_animation->setStartValue(m_group->pos());
m_animation->setEndValue(QPointF(1000.0,10.0));
m_animation->start();
}

}


This has been tested on Linux and Windows with debug and release having the same result.

Thanks in advance for any help/hints!