Progress bar is not smooth

Witc

I use progress bar (QML/Pyside), although I decrease the Value (by one) of progress bar every 20 ms (does not matter it is same for 1 and 100 ms), it looks like the Progress bar jumps from 100->80->60->40->20->0. There are not smooth progress 100,99,98,97,96.... What am I doing wrong?

Timer{
        id:timProgress
        interval: 20
        running: true
        repeat: true
        onTriggered: {
            if(prgVal1>0){
                   prgVal1 = prgVal1-0.1
            }      
        }
}

ProgressBar{
                    id: progressBar1
                    visible: true
                    width: 60
                    height: 20                  
                    value: prgVal1
                    from:0
                    to: 100
                              
                }

You can see GIF here: https://ibb.co/Wk4w2bn
Can anyone help me please?

ndias

@Witc

I was able to reproduce the problem on my side. I have tested it using Qt6 on Windows OS.

If no one provides feedback on how to resolve the issue, maybee you can open a new ticket on bug report system providing a description and a minimal script reproducing the issue.

Regards

dan1973

"repeat: true" should be "repeat: false"

i think the timer function onTriggered: is repeated continuously to make the prgVal1 reach from100 to 80 and 80 to 60...

Please check

Witc

@dan1973 said in Progress bar is not smooth:

"repeat: true" should be "repeat: false"

i think the timer function onTriggered: is repeated continuously to make the prgVal1 reach from100 to 80 and 80 to 60...

Please check

Do you think to set timer repeate to false?: When I do, the callback is called only once. When I added at the end of callback timer.start() - it still do the same - it "jumps" 100/80/...

dan1973

@Witc said in Progress bar is not smooth:

Do you think to set timer repeate to false?: When I do, the callback is called only once. When I added at the end of callback timer.start() - it still do the same - it "jumps" 100/80/..

I tried using cpp and h files rather in Qml below it works smoothly. Maybe you should do some settings in Qml to make it fire at 20ms and set value of Progressbar each time by 1 unit.

.h file

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QProgressBar>
#include <QTimer>

QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE

class Widget : public QWidget
{
    Q_OBJECT

public:
    Widget(QWidget *parent = nullptr);
    ~Widget();
    int iTick;

private slots:
    void MySlot();
    void vcPgb1(int);

private:
    Ui::Widget *ui;

    QProgressBar* pgb1;
    QTimer* tmr1;
};
#endif // WIDGET_H

.cpp file

#include "widget.h"
#include "ui_widget.h"
#include <QDebug>

Widget::Widget(QWidget *parent) : QWidget(parent), ui(new Ui::Widget) {
    ui->setupUi(this);

    iTick = 0;
    pgb1 = new QProgressBar(this);
    pgb1->setRange(0, 1000);
    pgb1->setGeometry(20, 100, 600, 30);
    connect(pgb1, SIGNAL(valueChanged(int)), this, SLOT(vcPgb1(int)));

    tmr1 = new QTimer(this);
    connect(tmr1, SIGNAL(timeout()), this, SLOT(MySlot()));
    tmr1->start(20);
}

Widget::~Widget() {
    tmr1->stop();
    delete ui;    
}

void Widget::MySlot() {
    iTick++;
    pgb1->setValue(iTick);
}

void Widget::vcPgb1(int iVal) {
    qDebug() << "pgb1 Value: " << iVal;
}

Witc

I tried using cpp and h files rather in Qml below it works smoothly. Maybe you should do some settings in Qml to make it fire at 20ms and set value of Progressbar each time by 1 unit.

.h file
#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QProgressBar>
#include <QTimer>

QT_BEGIN_NAMESPACE

Also do not undesratnd well. But maybe? I tried this:

import QtQuick 
import QtQuick.Controls 6.3

ApplicationWindow {
    id: root
    visible: true
    minimumWidth: 840
    minimumHeight: 600

    property real prgVal1:100

    function updateProgress(){
            if(prgVal1>0){
                prgVal1 -= 0.1
            }
            else{
                prgVal1 = 100
            }
            progressBar1.value = prgVal1
    }
         

    Timer{
        id:timProgress
        interval: 10
        running: true
        repeat: true
        onTriggered: {
            updateProgress()
        }
    }

    
    ProgressBar{
        id: progressBar1
        visible: true
        width: 100
        height: 40
        x: 20
        y: 50
        value: 66
        from:0
        to: 100
    }

}


/*##^##
Designer {
    D{i:0;autoSize:true;height:480;width:640}D{i:2}D{i:3}D{i:4}D{i:5}D{i:6}D{i:1}
}
##^##*/

It also does not work to me.

dan1973

Try this in xml

import QtQuick 2.15
import QtQuick.Controls 2.15

ApplicationWindow {
    id: root
    visible: true
    minimumWidth: 840
    minimumHeight: 600

    property real prgVal1:100

    function updateProgress(){
            if(prgVal1>0){
                prgVal1 -= 0.1
            }
            else{
                prgVal1 = 100
            }
            progressBar1.value = prgVal1
            console.log("prgVal1 = ", prgVal1);
    }


    Timer{
        id:timProgress
        interval: 10
        running: true
        repeat: true
        onTriggered: {
            updateProgress()
        }
    }


    ProgressBar{
        id: progressBar1
        visible: true
        width: 600
        height: 60
        x: 20
        y: 50
        value: 100
        from: 0
        to: 100
    }

}

Witc

@dan1973 said in Progress bar is not smooth:

import QtQuick 2.15
import QtQuick.Controls 2.15

It Still "jumps"... In console the prgVal is correct: 100/99,9/99,8/99,7/99,6....

dan1973

@Witc said in Progress bar is not smooth:

It Still "jumps"...

what is the System configuration of yours: RAM, Processor and OS?

dan1973

I checked it is moving smoothly without breaks or jagging

Witc

@dan1973 said in Progress bar is not smooth:

@Witc said in Progress bar is not smooth:

It Still "jumps"...

what is the System configuration of yours: RAM, Processor and OS?

Now I tried the same app on my friends PC (Ubuntu)- and it works great.
On my Windows 10, Dell, intel i7, 16GB RAM it is jagging

dan1973

@Witc said in Progress bar is not smooth:

On my Windows 10, Dell, intel i7, 16GB RAM it is jagging

your config above is Good Enough. Normally Qt requires min 4GB and 16GB will be enough to run any graphics. when you say intel i7 what's the processor speed.

You should check if any background process keeps windows busy in providing priority to your app. normally windows OS guarantees for more than 20ms.

if its over please mark solved. or any questions you can ask?

Witc

@dan1973 said in Progress bar is not smooth:

if its over please mark solved. or any questions you can ask?

unfortunatelly I have no idea how to solve it on my Computer, @ndias has the same problem as me, so ther is probably some bug in some verision of Qt? Python?....

dan1973

@Witc said in Progress bar is not smooth:

probably some bug in some verision of Qt?

which Qt version r u using? and which compiler?

Witc

@dan1973 said in Progress bar is not smooth:

@Witc said in Progress bar is not smooth:

probably some bug in some verision of Qt?

which Qt version r u using? and which compiler?

QT 6.3.1:

jsulm

@Witc This does not answer the question which compiler you're using as you installed Qt for ARM64, MSVC2019, WebAssembly, Android and MinGW...

Witc

@jsulm said in Progress bar is not smooth:

@Witc This does not answer the question which compiler you're using as you installed Qt for ARM64, MSVC2019, WebAssembly, Android and MinGW...

I am using Qt along with python 3.10 + Pyside6. No any line of my code is written in C/C++ ...

Marko Stanke

Tried it on Qt 5.15, and it works perfectly