How to draw a full circle with image - iphone

Question

I'm pretty new with core graphics. I need to draw a full circle. How do I go about it? I currently have a masked circle.
I referred to this example.
//Use the draw rect to draw the Background, the Circle and the Handle
-(void)drawRect:(CGRect)rect{
[super drawRect:rect];
CGContextRef ctx = UIGraphicsGetCurrentContext();
/** Draw the Background **/
//Create the path
CGContextAddArc(ctx, self.frame.size.width/2, self.frame.size.height/2, radius, 0, M_PI *2, 0);
// CGContextFillEllipseInRect(ctx, CGRectMake(self.frame.size.height/2, self.frame.size.width/2, 100, 100));
// CGContextSetRGBFillColor(ctx, 0.5, 0.5, 0.5, 1.0);
//Set the stroke color to black
[[UIColor greenColor]setStroke];
//Define line width and cap
CGContextSetLineWidth(ctx, TB_BACKGROUND_WIDTH);
CGContextSetLineCap(ctx, kCGLineCapButt);
CGContextDrawPath(ctx, kCGPathStroke);
UIGraphicsBeginImageContext(CGSizeMake(TB_SLIDER_SIZE,TB_SLIDER_SIZE));
CGContextRef imageCtx = UIGraphicsGetCurrentContext();
CGContextAddArc(imageCtx, self.frame.size.width/2 , self.frame.size.height/2, radius, 0, ToRad(self.self.startAngle), 0);
[[UIColor redColor]set];
CGContextSetLineWidth(imageCtx, TB_LINE_WIDTH);
CGContextDrawPath(imageCtx, kCGPathStroke);
//save the context content into the image mask
CGImageRef mask = CGBitmapContextCreateImage(UIGraphicsGetCurrentContext());
UIGraphicsEndImageContext();
CGContextSaveGState(ctx);
CGContextClipToMask(ctx, self.bounds, mask);
CGImageRelease(mask);
//list of components
CGFloat components[8] = {
0.0, 0.0, 1.0, 1.0, // Start color - Blue
1.0, 1.0, 1.0, 1.0 }; // End color - Violet
CGColorSpaceRef baseSpace = CGColorSpaceCreateDeviceRGB();
CGGradientRef gradient = CGGradientCreateWithColorComponents(baseSpace, components, NULL, 2);
CGColorSpaceRelease(baseSpace), baseSpace = NULL;
//Gradient direction
CGPoint startPoint = CGPointMake(CGRectGetMidX(rect), CGRectGetMinY(rect));
CGPoint endPoint = CGPointMake(CGRectGetMidX(rect), CGRectGetMaxY(rect));
//Draw the gradient
CGContextDrawLinearGradient(ctx, gradient, startPoint, endPoint, 0);
CGGradientRelease(gradient), gradient = NULL;
CGContextRestoreGState(ctx);
/** Draw the handle **/
[self drawTheHandle:ctx];
}

Answer 1

CGContextDrawPath(imageCtx, kCGPathFill);

Answer 2

make the backgroup width and line width to 140 and it works!!
#define TB_BACKGROUND_WIDTH 140 //The width of the dark background
#define TB_LINE_WIDTH 140 //The width of the active area (the gradient) and the width of the handle