Define CGPoint having angle and diameter
core-graphics, ios, iphone
Solution
A point on a circle with radius `r` at angle `a` (where `a` is measured from the rightmost point of the circle has the following coordinates:
x = r*cos(a) + center.x
y = r*sin(a) + center.y
Problem
I believe for some could be very simple to answer and help me. I have a circle defined in drawRect and wrote a code to define arc of the circle. ``` CGFloat width = rect.size.width-rect.origin.x; CGFloat height = rect.size.height-rect.origin.y; CGFloat xPos = rect.origin.x; CGFloat yPos = rect.origin.y; CGFloat arcStake = (width * 2) * 0.25; CGFloat radius = height/2; CGPoint centre = CGPointMake(xPos+width/2, yPos+height/2); CGFloat angle = acos(arcStake/(2*radius)); CGFloat startAng = radians(180) + angle; CGFloat endAng = radians(360) - angle; // Define 2 CGPoints of arc CGMutablePathRef path = CGPathCreateMutable(); CGPathAddArc(path, NULL, centre.x, centre.y, radius, startAng, endAng, 0); CGPathAddLineToPoint(path, NULL, xPos+width/2, yPos+height/2); CGPathCloseSubpath(path); ``` What I want is to define 2 CGPoints of arc. Here is the image to make it clearer.