Question

this is the formular but i dont know how to implement it. can someone please help

rectangle::rectangle()  //rectangle constructor
{
    bl.real() = 0; //bottom
    bl.imag() = 0; //left

    tr.real() = 1; //top
    tr.imag() = 1; //right
}

complex<double> rectangle::get_bl() const
{
    return bl;
}

complex<double> rectangle::get_tr() const
{
    return tr;
}

void rectangle::rotate(double angle)
{
    //not sure how to do it  tr = tr.real() * cos(angle) + tr.imag() *cos(angle);


}

main

rectangle r;
r.rotate(90);

expected output (not 100% sure)

0 0 -1 1

Answer 1

1. Move your shape to (0, 0) temporarily (formula assumes you are rotating about origin, so move the bottom-left corner to (0, 0)).
2. Apply formula.
3. Move it back.

---

if (tr.real() < bl.real()) {
  float tempX = tr.real() - bl.real();
  float tempY = tr.imag() - bl.imag();
} else {
  float tempX = bl.real() - tr.real();
  float tempY = bl.imag() - tr.imag();
}

tr.real() = tempX * cos(theta) - tempY * sin(theta)
tr.imag() = tempx * sin(theta) + tempY * cos(theta)