Bill Dani - 9 months ago 73

iOS Question

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

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.

Answer

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