Question

I am trying to draw a circle (small like a dot) at the exact point of a UITouch.

The problem is, when I get the touchPoint from the user touch, I have to then draw the Rect in which to place the circle.

To work out an origin for the Rect, to place it such that, a circle drawn within it will have a centre point at the original touchpoint, I have used Pythagorus’ theorem.

However, this approach is not elegant and is not exact.

Is there a better way to do this?

UITouch *touch = obj;
CGPoint touchPoint = [touch locationInView:self.view];

CGContextAddEllipseInRect(context,(CGRectMake ((touchPoint.x - 5.7), (touchPoint.y - 5.7)
                                                   , 9.0, 9.0)));

Answer 1

you can do like below

  CFFloat radius=10;
  UITouch *touch = obj;
  CGPoint touchPoint = [touch locationInView:self.view];

  CGContextAddEllipseInRect(context,(CGRectMake ((touchPoint.x - radius/2), (touchPoint.y 
                                              - radius/2)
                                               , radius, radius)));