Delay function

saivineeth

Hi
I was creating a sine wave by using canvas how to add delay function
Can someone help me to solve it how to add how to us

import QtQuick 2.9
import QtQuick.Window 2.15

Window {

    function timer() {
        return Qt.createQmlObject("import QtQuick 2.0; Timer {}", root);
    }

    id:screen
    visible:true
    height: 1080
    width: 1920
    title: qsTr("SineWave")
    Rectangle{
        height:parent.height
        width:parent.width
        Timer {
            id: timer
        }

        function delay(delayTime, cb) {
            timer.interval = delayTime;
            timer.repeat = false;
            timer.triggered.connect(cb);
            timer.start();
        }
        Canvas{
            id:canvas
            anchors.fill:parent
            onPaint: {
                var ctx = getContext("2d");
                var cw = parent.width;
                var ch = parent.height;
                var  cx = cw, cy = ch/2;
                var w= width;
                var h= height;
                ctx.lineWidth= 4;
                ctx.clearRect(0, 0, cw, ch);
                ctx.beginPath();
                ctx.moveTo(0, cy);

                for(var x=0;x<1921;x++){
                    var y = Math.sin(x/305);
                    ctx.lineTo(x, cy+(y*400));//now you add delay of 1sec
                    console.log(y)
                }//from here the sine wave is plotted from left to right clean the screen with small from left to right


                ctx.stroke();
                showMaximized(Window)
            }
        }
    }
}

sierdzio

What kind of delay? Is Qt.callLater() enough?

saivineeth

@sierdzio no i am creating wave in qml

sierdzio

OK and you want to delay the painting?

Or you ask how to mathematically delay the sine so it starts at a different value?

saivineeth

@sierdzio once check the code and tell me how to solve it i add timer where i need to call it
I don't know about timmer i was trying it can u help me out
I need output like i need a delay 1 millisecond between 1 plotting to another plotting

sierdzio

Just throw in await sleep(1); at the end of your JS code, then.