iOS Draw Circle

/* ADD an arc of a circle to the context's path, possibly preceded by a

Straight line segment. ' (x, y) ' is the center of the arc; ' Radius ' is its

Radius ' StartAngle ' is the angle to the first endpoint of the arc;

' Endangle ' is the angle to the second endpoint of the arc; and

' Clockwise ' is 1 if the arc was to be drawn clockwise, 0 otherwise.

' StartAngle ' and ' endangle ' is measured in radians. */

　 " (x, y)" is the center of the arc, and "radius" is its radius; StartAngle "is the end point of the first angular arc; Arc Angle of the second endpoint of "Endangle";

"Clockwise" = = 1 arc is clockwise, otherwise 0.

The radian of "startangle" and "Endangle measurement".

Cg_extern void Cgcontextaddarc (Cgcontextref C, CGFloat x, CGFloat y,

CGFloat radius, cgfloat startangle, cgfloat endangle, int clockwise)

Cg_available_starting (__mac_10_0, __iphone_2_0);

Cgcontextaddarc (context, x, Y, 3, 0, 2*PI, 0); Add a circle with a radius of 3 (x, y) with a circumference of 2*pi,

iOS Draw Circle