getPointOnArc function
get point coordinate/first derivative at parameter t on an arc
Implementation
Offset getPointOnArc(Rect rect, double t) {
double xc = rect.center.dx,
yc = rect.center.dy,
rx = rect.width / 2,
ry = rect.height / 2;
return Offset(xc + rx * cos(t), yc + ry * sin(t));
}