QPropertyAnimation use so much system resource when using to create a simple Indeterminate Progressbar

saeid0034

hi, Im creating a simple progress bar for my program, I also need it to support an Indeterminate mode, so what I did for it is using QPropertyAnimation to create a offset in infinite loop, and then draw the progress bar based of that
here is a code snippet from what I have

class QProgressDelegate(QObject):
    def __init__(self, _parent):
        super().__init__()
        self.m_progress = _parent
        self.m_offset = 0

    def get_offset(self):
        return self.m_offset

    def set_offset(self, value:float):
        self.m_offset = value
        self.m_progress.update()

    offset = Property(float, get_offset, set_offset)

# and then use it like this
    self.delegate = QProgressDelegate(self)

    self.animation = QPropertyAnimation(self)
    self.animation.setPropertyName(b"offset")
    self.animation.setTargetObject(self.delegate)
    self.animation.setStartValue(0)
    self.animation.setEndValue(1)
    self.animation.setDuration(1000)
    self.animation.setLoopCount(-1)

# in paint event
    ...
    painter.drawRect(self.delegate.offset*self.width()*2-self.width(), 0, self.width(), self.height())
    ...

but the problem is, its use like 10% of cpu when running, and I think its too much... so Im thinking maybe I'm doing it wrong? if yes can anyone point me to a better way?

SGaist

Hi,

Why not just use the standard QProgressBar procedure for "infinite bar" ?

As the doc says, set both minimum and maximum to 0 and voila, you have a busy indicator.

saeid0034

@SGaist because I can make it more beautiful in this way, and also it can suit my needs a little better
Progress Bar
I'm not sure if I can achieve something like this with stylesheet...

SimonSchroeder

@saeid0034 said in QPropertyAnimation use so much system resource when using to create a simple Indeterminate Progressbar:

but the problem is, its use like 10% of cpu when running, and I think its too much... so Im thinking maybe I'm doing it wrong?

In general, I expect QPropertyAnimation to be used for short animations. It is likely that it will just run whenever the event queue is idle to make animations as smooth as possible. If you don't have anything else running, it might use up a whole core (is 10% of a single core or all cores together?).

If this is actually the problem then I would suggest to use a QTimer with 10ms or 50ms resolution and drop the QPropertyAnimation altogether. (Remember 60Hz is about 16ms and even 30Hz is probably smooth enough.)

saeid0034

@SimonSchroeder thank you for reply
I tried to create a custom progress bar with stylesheet, but result was not what I after...
about QTimer, tbh I dont know how can I use it instead of QPropertyAnimation...
I mean can I used like how I use QPropertyAnimation? I mean use it to set the QProperty?

SimonSchroeder

@saeid0034 said in QPropertyAnimation use so much system resource when using to create a simple Indeterminate Progressbar:

I mean can I used like how I use QPropertyAnimation? I mean use it to set the QProperty?

Yes, that is exactly right that when the QTimer times out you compute the offset based on the elapsed time and then set the QProperty accordingly.