getDistance

Code

var bg = new Path.Rectangle({
    size: view.size,
    fillColor: 'black'
})

    
var path = new Path.Circle({
    radius: 100,
    strokeColor: 'lightGreen',
    strokeWidth: 5,
    center: view.center,
    applyMatrix: false
})

var cursor = new Path.Circle({
    radius: 20,
    fillColor: '#C39C98',
    center: view.center
})

cursor.onMouseDrag = function(event){
    cursor.position += event.delta
    var distance = 1/(view.size.width/path.position.getDistance(cursor.getNearestPoint(cursor.position)))
    updateCircle(distance)
}

function updateCircle(distance){
    path.scaling = distance
}