CODEWITHSUNDEEP
iosxcodeswiftgeometry
Eliko
Eliko

Reputation: 1137

Using UIBeizerPath on Circle

I want to make a circle which can be cut by percent, for example, 0.25 is 1/4 of the circle.

This is my code so far:

let circlePath = UIBezierPath(arcCenter: CGPoint(x: 100,y: 300), radius: CGFloat(20), startAngle: CGFloat(M_PI + M_PI_2), endAngle:CGFloat(90 * M_PI / 180, clockwise: true)

        let shapeLayer = CAShapeLayer()
        shapeLayer.path = circlePath.CGPath

        //change the fill color
        shapeLayer.fillColor = UIColor.clearColor().CGColor
        //you can change the stroke color
        shapeLayer.strokeColor = UIColor.redColor().CGColor
        //you can change the line width
        shapeLayer.lineWidth = 3.0

        view.layer.addSublayer(shapeLayer)

In startAngle I wrote CGFloat(M_PI + M_PI_2) because the start of the circle doesnt start in 0 but as in this picture:

enter image description here

In the endAngle line I wrote CGFloat(90 * M_PI / 180) because the formula from degrees to radians is: degrees*pi/180 .

BUT! In the view I get half of the circle and not quarter of the circle:

enter image description here

Does my endAngle formula is wrong?

Upvotes: 0

Views: 264

Answers (2)

Eliko
Eliko

Reputation: 1137

Because in iOS the top of the circle starts at 270 degrees, the startAngle is: 

startAngle: CGFloat(M_PI + M_PI_2)

And the endAngle is:

endAngle:CGFloat((360 * 0.25 - 90)

Instead of 0.25, you can change it to any number between 0 to 1 (for example: if you want half of the circle to be full, change it to 0.5)

Upvotes: 0

Ethan
Ethan

Reputation: 1567

I think what you want is for your start angle to be 0 and your end angle to be 90 * PI/180

What you have now is a curve that starts at the bottom 270, aka M_PI + M_PI/2 and goes to 90 (90 * M_PI / 180)

//Possibly what you want is for your endAngle = (90 * M_PI/180) + startAngle , aka a quarter more than where you started, i'm not sure which quarter of the circle you want

Upvotes: 2

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