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iosuikitcore-graphicsuibezierpath

UIBezierPath circle get specific points

I would like to draw one big circle and place some smaller circles as shown in the image below

circle

I draw the big circe in - (void)drawRect:(CGRect)rect

CGFloat rectX = self.frame.size.width / 2;
CGFloat rectY = self.frame.size.height / 2;

CGFloat width = self.frame.size.width-30;
CGFloat height = self.frame.size.width -30;

CGFloat centerX = rectX - width/2;
CGFloat centerY = rectY - height/2;


UIBezierPath *bezierPath = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(centerX, centerY, width, height)];

[[UIColor blackColor] set];
[bezierPath stroke];

Lets say I want to find 10 equally spaced points on the circle in order to draw 10 smaller red circles. Is there any smart solution? Thank you in advance.

Solution

  • The equation for a circle is:

    x = cx + r * cos(a)
y = cy + r * sin(a)

    where r is the radius, (cx, cy) the origin, and a the angle

    you can draw a circle with 

    (UIBezierPath *)bezierPathWithArcCenter:(CGPoint)center radius:(CGFloat)radius startAngle:(CGFloat)startAngle endAngle:(CGFloat)endAngle clockwise:(BOOL)clockwise

    function by using a CGPoint as centre and some value as the radius. You can give start angle and endangle as 0 and 360 for drawing the circle. Choose appropriate radius for the small circle and find the points using the equation mentioned at start and draw the circle