Get end points of circle drawn in ObjectiveC

Question

I am drawing a circle in a UIView using the drawRect method. I am using the following code to draw it.

- (void)drawRect:(CGRect)rect
{
     CGContextRef context = UIGraphicsGetCurrentContext();
     CGContextAddArc(context, 105, 105, 55, [self convertDegreeToRadian:15.0], [self convertDegreeToRadian:345.0], 0);
     CGColorRef black = [[UIColor blackColor] CGColor];
     CGContextSetStrokeColorWithColor(context, black);
     CGContextStrokePath(context);
}

This gives me a curve from 15 degrees to 345 degrees. So, this curve is drawn from one point to another. I need to get the points of the two edges. How do I get it?

if it is a circle means , end point and start point might be same — Milad Rezazadeh, Jul 19 '13 at 06:29
@borrrden Too bad we can't mark questions as dupes of questions on *another sites,* e. g. math.SE in this case. — , Jul 19 '13 at 06:31
@H2CO3 I guess the best would be to throw it over there and have *them* mark it as a duplicate :p — borrrden, Jul 19 '13 at 06:33

Mick MacCallum · Answer 1 · 2014-02-17T12:47:12.183

If you're looking to calculate a point on the circumference of a circle, this function should help. It returns a CGPoint and takes parameters that are pretty self-explanatory; a center point for a the circle, the circle's radius, and the angle of rotation in radians.

- (CGPoint)pointAroundCircumferenceFromCenter:(CGPoint)center withRadius:(CGFloat)radius andAngle:(CGFloat)theta
{
    CGPoint point = CGPointZero;
    point.x = center.x + radius * cos(theta);
    point.y = center.y + radius * sin(theta);

    return point;
}

Get end points of circle drawn in ObjectiveC

1 Answers1