I have coded as below for half circle in iOS using UIBezierPath and CAShapeLayer.
clockWiseLayer = [[CAShapeLayer alloc] init];
CGFloat startAngle = -M_PI_2;
CGFloat endAngle = M_PI + M_PI_2;
CGFloat width = CGRectGetWidth(imageView.frame)/2.0f + 30;
CGFloat height = CGRectGetHeight(imageView.frame)/2.0f +50;
CGPoint centerPoint = CGPointMake(width, height);
float radius = CGRectGetWidth(imageView.frame)/2+10;
clockWiseLayer.path = [UIBezierPath bezierPathWithArcCenter:centerPoint
radius:radius
startAngle:startAngle
endAngle:endAngle
clockwise:YES].CGPath;
clockWiseLayer.fillColor = [UIColor clearColor].CGColor;
clockWiseLayer.strokeColor = [UIColor blueColor].CGColor;
clockWiseLayer.borderColor = [UIColor greenColor].CGColor;
clockWiseLayer.backgroundColor = [UIColor redColor].CGColor;
clockWiseLayer.strokeStart = 0.0f;
clockWiseLayer.strokeEnd = 0.5f;
clockWiseLayer.lineWidth = 2.0f;
clockWiseLayer.borderWidth = 5.0f;
clockWiseLayer.shouldRasterize = NO;
[self.layer addSublayer:clockWiseLayer];
This results as below.
I want this blue half circle on the opposite side of the World Globe.
It is half Circle, but I want it on the other side, also CounterClockWise.
I am unable to set start and end angle for that, while clockwise:NO.
Thanks.
Check documentation for coordinates: http://i.stack.imgur.com/1yJo6.png
Y-Axis is reversed compared to standard coordinate system in mathematics.
You should draw from 1/2*PI (bottom anchor) to 3/2*PI (top anchor) and then you set strokeStart to 0.0f and strokeEnd to 1.0f (so it fills whole path).
Working code using iOS constants:
CGFloat startAngle = M_PI_2;
CGFloat endAngle = startAngle + M_PI;
CGFloat width = CGRectGetWidth(imageView.frame)/2.0f;
CGFloat height = CGRectGetHeight(imageView.frame)/2.0f;
CGPoint centerPoint = CGPointMake(width, height);
float radius = CGRectGetWidth(imageView.frame)/2+10;
CAShapeLayer* clockWiseLayer = [[CAShapeLayer alloc] init];
clockWiseLayer.path = [UIBezierPath bezierPathWithArcCenter:centerPoint
radius:radius
startAngle:startAngle
endAngle:endAngle
clockwise:YES].CGPath;
clockWiseLayer.fillColor = [UIColor clearColor].CGColor;
clockWiseLayer.strokeColor = [UIColor blueColor].CGColor;
clockWiseLayer.borderColor = [UIColor greenColor].CGColor;
clockWiseLayer.backgroundColor = [UIColor redColor].CGColor;
clockWiseLayer.strokeStart = 0.0f;
clockWiseLayer.strokeEnd = 1.0f;
clockWiseLayer.lineWidth = 2.0f;
clockWiseLayer.borderWidth = 5.0f;
[self.layer addSublayer:clockWiseLayer];