android - How to create a resizable circle with user touch events? -

i trying create circle shape resized on ontouchevent.

i have followed resizable rectangle post, think due lack of mathematics knowledge, not getting how create resizeable circle.

i have tried changing

canvas.drawrect(     left + colorballs.get(0).getwidthofball() / 2,     top + colorballs.get(0).getwidthofball() / 2,      right + colorballs.get(2).getwidthofball() / 2,      bottom + colorballs.get(2).getwidthofball() / 2, paint); 

to canvas.drawcircle(); creates circle not quite wanted.

can please tell me there thing implemented or points should follow convert rectangle example resizable circle.

so, center of circle be:

float cx = (left + right) / 2f;  float cy = (top + bottom) / 2f;  

-- quite obvious. radius can calculated using math.hypot():

float radius = math.hypot(top - bottom, right - left) / 2f; 

thus, have center , radius draw circle:

drawcircle(cx, cy, radius, paint);