Spirala Ulama

// main.cpp
#include <QGuiApplication>
#include <QQmlApplicationEngine>

int main(int argc, char *argv[])
{
    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);

    QGuiApplication app(argc, argv);

    QQmlApplicationEngine engine;
    engine.load(QUrl(QStringLiteral("main.qml")));
    if (engine.rootObjects().isEmpty())
        return -1;

    return app.exec();
}

// main.qml
import QtQuick 2.9
import QtQuick.Window 2.2

Window {
    id: mainwindow
    visible: true
    width: 1200
    height: 1000
    title: qsTr("Hello World")
    property variant punkty: [];

    Component.onCompleted: {
        spirala()
    }

    function isPrime(n) {
        var sn = Math.sqrt(n);
        for (var i = 2; i <= sn; i++) {
            if (!(n%i)) return false;
        }
        return true;
    }

    function liczbaPol(n) {
        var res = 9;
        var tmp = 16;
        for (var i = 2; i <= n; i++) {
            res += tmp;
            tmp += 8;
        }

        return res;
    }

    function spirala() {
        var x = 590;
        var y = 490;

        var ds = 20;
        var dx = 1;
        var dy = -1;

        var mx = true;
        var su = 0;
        var m = 1;
        var kl = 2, ki = 0, km = 0;
        var suma = 1;
        var lp = liczbaPol(20);
        var cp = 1, clp = 0;

        for (var j = 1, k = 0; j <= lp; j++) {
            punkty.push(Qt.createQmlObject('Rect { x: ' + x + '; y: ' + y + '; number: ' + j + ' }', mainwindow));

            if (ki >= kl) {
                cp++;
                if (isPrime(j)) {
                    punkty[j-1].textColor = "red";
                    clp++;
                }

                suma += j;
                ki = 0;
                km++;
            }
            ki++;

            if (km >= 4) {
                kl += 2;
                km = 0;
            }

            if (mx) x += dx*ds;
            else y += dy*ds;
            k++;
            if (k == m) {
                mx = !mx;
                su++;
                k = 0;
            }
            if (su == 2) {
                m++;
                dx *= -1;
                dy *= -1;
                su = 0;
            }
        }

        console.log(clp, '/', cp, ' ', Math.round((clp/cp)*100), '%');
    }
}

// Rect.qml
import QtQuick 2.0

Rectangle {
    id: root

    property int number
    property color borderColor: "transparent"
    property color textColor: "black"
    property int size: 20

    width: size;
    height: size;
    border.width: 1;
    border.color: borderColor;
    color: "transparent";

    Text {
        font.pointSize: 5
        color: textColor
        x: root.width/2 - width/2
        y: root.height/2 - height/2
        text: number
    }
}