I have an array that makes a rectangle using X and Y coordinates like this:

* Top Left
aShapeArray[1,1] = 10
aShapeArray[1,2] = 10

* Top Right
aShapeArray[2,1] = 20
aShapeArray[2,2] = 10

* Bottom Right
aShapeArray[3,1] = 20
aShapeArray[3,2] = 20

* Bottom Left
aShapeArray[4,1] = 10
aShapeArray[4,2] = 20

* Top Left again to close the shape
aShapeArray[5,1] = 10
aShapeArray[5,2] = 10

What loop/math can I use to create a rounded corner shape?

For example, if I add four more points to the array (ignore the actual subscripts, the are just at the four corners):

aShapeArray[1,1] = 25
aShapeArray[1,2] = 5

aShapeArray[1,1] = 25
aShapeArray[1,2] = 15

aShapeArray[1,1] = 5
aShapeArray[1,2] = 15

aShapeArray[1,1] = 5
aShapeArray[1,2] = 5

This will create an octagon. If I kept adding various points, I could end up with a circle. There must be a way to calculate that using another value, like 100 for a circle (or ellipse) and 0 for a square (or rectangle) and create the array used to create the shape.

Or if someone knows a resource that would help me do this.

These array points were not actually tested, but the idea hopefully is clear.