rotatePoint function
Rotates point around center by degrees.
Implementation
Offset rotatePoint(Offset point, Offset center, double degrees) {
final radians = degrees * math.pi / 180.0;
final cosA = math.cos(radians);
final sinA = math.sin(radians);
final translated = point - center;
final rotated = Offset(
translated.dx * cosA - translated.dy * sinA,
translated.dx * sinA + translated.dy * cosA,
);
return rotated + center;
}