Core Graphics - Shadow not seen - ios

Question

I wrote a simple drawRect with a intention of drawing a circle, drop a shadow and fill it with blue. I have successfully achieved drawing a circle and filling it in blue but my shadow is not in effect. Instead of fill if I stroke my circle, i see the shadow is inside the circle and during fill it is drawn over by fill colour
rect to my drawRect has dimension [[CustomButton alloc]initWithFrame:CGRectMake(0, 0, 50, 50)];
#implementation CustomButton
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self)
{
[self setBackgroundColor:[UIColor clearColor]];
}
return self;
}
- (void)drawRect:(CGRect)rect
{
CGContextRef context = UIGraphicsGetCurrentContext();
CGColorRef colorRef = [[UIColor blueColor] CGColor];
CGContextSetStrokeColorWithColor(context, colorRef);
CGContextSetFillColorWithColor(context, [[UIColor blueColor] CGColor]);
CGRect buttonRect = CGRectInset(rect, 3, 3);
CGPoint centerPoint = CGPointMake(CGRectGetMidX(buttonRect ), CGRectGetMidY(buttonRect));
CGFloat radius = CGRectGetWidth(buttonRect) / 2;
CGContextSaveGState(context);
CGContextSetShadow(context, CGSizeMake(15.0, 20.0), 1.0);
CGContextAddArc(context, centerPoint.x, centerPoint.y, radius, 0, 2*M_PI, 1);
CGContextClip(context);
CGContextFillRect(context, buttonRect);
CGContextRestoreGState(context);
CGColorRelease(colorRef);
}
#end
Thank you

Answer 1

Try this:
- (void)drawRect:(CGRect)rect
{
CGContextRef context = UIGraphicsGetCurrentContext();
CGColorRef colorRef = [[UIColor blueColor] CGColor];
CGContextSetStrokeColorWithColor(context, colorRef);
CGContextSetFillColorWithColor(context, [[UIColor blueColor] CGColor]);
CGRect buttonRect = CGRectInset(rect, 3, 3);
CGPoint centerPoint = CGPointMake(CGRectGetMidX(buttonRect ), CGRectGetMidY(buttonRect));
CGFloat radius = CGRectGetWidth(buttonRect) / 2;
CGContextSaveGState(context);
CGContextSetShadow(context, CGSizeMake(2.0, 2.0), 2.0);
CGContextAddArc(context, centerPoint.x, centerPoint.y, radius, 0, 2*M_PI, 1);
//CGContextClip(context);
CGContextFillPath(context);
CGContextRestoreGState(context);
CGColorRelease(colorRef);
}
Your shadow was rectangular and that is why it was not seen under the circle. I changed the call CGContextFillRect to CGContextFillPath, the path which you already create using CGContextAddArc.
Is this what you were going for?
EDIT
You can find a project here: https://bitbucket.org/reydan/so_circleshadow