QML Animation with both "velocity" and infinite "loops" - qt

Question

I'm trying to put together an animation in which I get to specify the velocity (rather than the duration) and which loops forever. I came up with two non-working examples:
FirstTry.qml
import Qt 4.7
Rectangle {
width: 100; height: 100
Text {
text: "hello"
NumberAnimation on x {
to: 50;
loops: Animation.Infinite;
duration: 50 * Math.abs(to - from)
}
}
}
I get the following runtime warning while hello goes nuts on the screen (fair enough).
QDeclarativeExpression: Expression "(function() { return 50 * Math.abs(to - from) })" depends on non-NOTIFYable properties:
QDeclarativeNumberAnimation::to
QDeclarativeNumberAnimation::from
SecondTry.qml
import Qt 4.7
Rectangle {
width: 100; height: 100
Text {
text: "hello"
SmoothedAnimation on x {
to: 50;
loops: Animation.Infinite;
velocity: 50
}
}
}
This is more of a mistery -- SmoothedAnimation simply refuses to loop! The Animation runs once and then that's it.
So I have the following questions:
Is there a legal way to specify the velocity in the first example? I understand SmoothedAnimation is derived from NumberAnimation, so maybe it's possible in QML, not just in C++.
Is there a way to make SmoothedAnimation loop? Is the second example not working a bug or am I missing something?
Is there any other way to achieve these two behaviours at the same time?

Answer 1

just add "from" parameter explicitly:
import Qt 4.7
Rectangle {
width: 100; height: 100
Text {
text: "hello"
NumberAnimation on x {
from: 0;
to: 50;
loops: Animation.Infinite;
duration: 50 * Math.abs(to - from)
}
}
}

Answer 2

This is what I did as a temporary solution, I'm not sure if it's adequate, but it seem to be doing just what I needed.
SmoothedAnimation on x {
to: 50;
//loops: Animation.Infinite;
velocity: 50
onComplete: { restart (); }
}
I'm still interested in the answers to the questions, though.

Answer 3

Even if SmoothedAnimation doesn't accept loops parameter, you can place it inside SequentialAnimation and apply loops to this external cover. As an effect your smoothed animation will be played continuosly.