Question

For an iPhone application I want to draw a circle, that is only for an x percentage filled.

Something like this:

I have no problems calculating the radius, the degrees or the radians, that is no problem. Also drawing the circle is already done. But how do I get the iPhone SDK to draw the part that is filled.

I can draw a rectangle that size, but not part of a circle.

I just want to draw that on a a normal context.

Hope someone can give me any pointers here.

Answer 1

Use CGContext‘s arc functions:

CGContextAddArc(context,
                centerX,
                centerY,
                radius,
                startAngleRadians,
                endAngleRadians,
                clockwise ? 1 : 0);     

See the documentation for CGContextAddArc().