Function reversePolygon

docs/app/js/sanddance-app.js:101655–101668

(points, options)

    if (!isClosedEx) visitor(points[endPointIndex], points[endPointIndex + 1], points[start], points[start + 1], numPoints - 1, 0);
}
function reversePolygon(points, options) {
    const { start =0 , end =points.length , size =2  } = options;
    const numPoints = (end - start) / size;
    const numSwaps = Math.floor(numPoints / 2);
    for(let i = 0; i < numSwaps; ++i){
        const b1 = start + i * size;
        const b2 = start + (numPoints - 1 - i) * size;
        for(let j = 0; j < size; ++j){
            const tmp = points[b1 + j];
            points[b1 + j] = points[b2 + j];
            points[b2 + j] = tmp;
        }
    }
}
function modifyPolygonWindingDirectionPoints(points, direction, options = {}) {
    const currentDirection = getPolygonWindingDirectionPoints(points, options);
    if (currentDirection !== direction) {