apply method
convert offset in topleft to others
Implementation
Offset apply(
Offset o, {
required double width,
required double height,
}) {
var v = this.toInt();
if (v == null) return o;
var dx = o.dx;
var dy = o.dy;
var halfWidth = width / 2;
var halfHeight = height / 2;
// calcute the x: & 0000 1111 = 15
// 3 1 5 => -1 0 1 => 0 1 2
// dx += ((v&15) / 2) * halfWidth;
// if (v&15 == 1) {
// dx += halfWidth;
// } else if (v&15 == 2) {
// dx += width;
// }
// // calcute the y: & 1111 0000 = 240
// // 48 16 80 => 0 1 2
// dy += ((v&240) / 2) * halfHeight;
return Offset(dx, dy);
}