Rotation of an image (in a loop) is not smooth although the fps is 60

[Guest]

I tried two different possibilities.

First:

@Image
{
id: media_cover
source: "../images/media_cover.png"
smooth: true
rotation: 0
transformOrigin: Item.Center
}@

@RotationAnimation
{
target: media_cover;
property: "rotation";
loops: Animation.Infinite;
from: 0;
to: 360;
duration: 8000
} @

Second:

@ Image
{
id: media_cover
source: "../images/media_cover.png"
smooth: true

        transform:
            Rotation {
            id: cover_rot
            origin.x: parent.width/2
            origin.y: parent.width/2
            angle: 0
            }

}
@

@NumberAnimation
{
target: cover_rot;
property: "angle";
loops: Animation.Infinite;
from: 0;
to: 360;
duration: 8000
}
@

Both options don't work.

I tried it on windows xp, windows 7, i.MX53 with Qt 4.8 and also with Qt 5 Alpha. Everywhere with the same result.

Is it a known problem of Qt or rather someone knows a solution for this problem.

[sierdzio]

AFAIK, it is a known problem, it was discussed a while ago on dev mailing list. Try porting to QtQuick2 if possible, just to see if it is still a problem there. On the other hand, animations are not smooth with QML2 on Linux... but maybe that was fixed, too.

[andre]

The perceived smoothness has to do with synchronization of the renderings with the updates of the screen by the underlying system (OpenGL, for instance). At least, that is how I understood the issue. See "this post":http://labs.qt.nokia.com/2010/12/02/velvet-and-the-qml-scene-graph/ for example.

[Guest]

Thank You for your answers, I forget to say that i tried it with QtQuick 2.0, too. There is the same Problem.