math_rotate – Rotate a point around origin https://codescreens.com

math_rotate.html

<!-- Rotate a point around origin -->
<!-- https://codepen.io/vbarbarosh/pen/joXEyR -->

<svg>
    <circle id="origin" cx="200" cy="150" r="10" />
    <circle id="point" cx="175" cy="125" r="5" />
</svg>  

<style>
svg {
    width: 400px;
    height: 300px;
    border: 1px dashed;
}
</style>

<script>
(function () {
    // http://stackoverflow.com/a/13208761/1478566
    function rotate(x, y, ox, oy, deg)
    {
        const rad = deg * Math.PI / 180.0;
        return {
            x: Math.cos(rad) * (x-ox) - Math.sin(rad) * (y-oy) + ox,
            y: Math.sin(rad) * (x-ox) + Math.cos(rad) * (y-oy) + oy
        };
    }

    let deg = 0;
    setInterval(function () {
        const {x, y} = rotate(175, 125, 200, 150, deg++);
        point.setAttribute('cx', x);
        point.setAttribute('cy', y);  
    }, 10);
})();
</script>