Getting Center and Radius of Irregural Object

Question

I have drawn an asteroid object manually , and would like to get its center/radius by a specific equation. I think I can get them by calculated and hard-coded values.

The code to draw the asteroid:

float ratio = (float)app::getWindowWidth()/app::getWindowHeight();
gl::pushMatrices();

gl::translate(m_Pos*ratio);

gl::scale(m_size*ratio,m_size*ratio);
gl::color(ci::Color(1,1,1));

    gl::drawLine(Vec2f(20,0),Vec2f(80,0));
    gl::drawLine(Vec2f(80,0),Vec2f(100,20));
    gl::drawLine(Vec2f(100,20),Vec2f(100,50));
    gl::drawLine(Vec2f(100,50),Vec2f(60,100));
    gl::drawLine(Vec2f(60,100),Vec2f(40,100));
    gl::drawLine(Vec2f(40,100),Vec2f(50,70));
    gl::drawLine(Vec2f(50,70),Vec2f(25,90));
    gl::drawLine(Vec2f(25,90),Vec2f(0,70));
    gl::drawLine(Vec2f(0,70),Vec2f(20,40));
    gl::drawLine(Vec2f(20,40),Vec2f(0,20));
    gl::drawLine(Vec2f(0,20),Vec2f(20,0));

gl::popMatrices();

gl::pushMatrices();

float radius = getRadius();

Vec2f center = Vec2f(m_Pos.x+50, m_Pos.y+50);

gl::drawStrokedCircle(center*ratio, 10);
gl::popMatrices();

}

According to the answer I have written that code to calculate the radius, is it correct or not ?

cinder::Vec2f Asteroid::getCenter()
{
    return ci::Vec2f(m_Pos.x, m_Pos.y);
}

double Asteroid::getRadius()
{
    ci::Vec2f  _vec = (getCenter()- Vec2f(15,5));
    return _vec.length()*0.3f; 
}

Answer 1

To get the center of the extents, take the max and min of both the x and y values, add them together and divide by two.

In your trivial example:

XMin = -15
XMax = 15
YMin = -5
YMax = 5

-15 + 15 = 0, 0/2 = 0
-5 + 5 = = 0, 0/2 = 0

So obviously the center is at (0,0)

The radius of the bounding circle is the largest distance from the center to a point that makes up the shape.