Reposition/resize UIBezierPath

Swift 3 extension (modify it with factorX, factorY if needed) :

extension UIBezierPath
{
    
    func scaleAroundCenter(factor: CGFloat)
    {
        let beforeCenter = self.bounds.getCenter()
        
        // SCALE path by factor
        let scaleTransform = CGAffineTransform(scaleX: factor, y: factor)
        self.apply(scaleTransform)
        
        let afterCenter = self.bounds.getCenter()
        let diff = CGPoint(
            x: beforeCenter.x - afterCenter.x,
            y: beforeCenter.y - afterCenter.y)
        
        let translateTransform = CGAffineTransform(translationX: diff.x, y: diff.y)
        self.apply(translateTransform)
    }

SWIFT 5 UPDATE

extension UIBezierPath {

    func scaleAroundCenter(factor: CGFloat) {
        let beforeCenter = CGPoint(x: self.bounds.midX, y: self.bounds.midY)

        // SCALE path by factor
        let scaleTransform = CGAffineTransform(scaleX: factor, y: factor)
        self.apply(scaleTransform)

        let afterCenter = CGPoint(x: self.bounds.midX, y: self.bounds.midY)
        let diff = CGPoint( x: beforeCenter.x - afterCenter.x, y: beforeCenter.y - afterCenter.y)

        let translateTransform = CGAffineTransform(translationX: diff.x, y: diff.y)
        self.apply(translateTransform)
    }

}

Swift version

Here is @hfossli's code for Swift:

// example path
let path = UIBezierPath(roundedRect: CGRect(x: 0, y: 0, width: 100, height: 100), cornerRadius: 4)

// scale it
let scale = CGFloat(0.9)
path.applyTransform(CGAffineTransformMakeScale(scale, scale))

// move it
let translation = CGSize(width: 10, height: 5)
path.applyTransform(CGAffineTransformMakeTranslation(translation.width,
    translation.height))

// apply it
self.myLayer.path = path

Update

I've found in actual practice that I just just different initial values when creating a UIBezierPath rather than transforming it later. I guess it would depend on the purpose.

// example path
UIBezierPath *path = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(0, 0, 100, 100) cornerRadius:4];

// scale it
CGFloat scale = 0.9;
[path applyTransform:CGAffineTransformMakeScale(scale, scale)];

// move it
CGSize translation = CGSizeMake(10, 5);
[path applyTransform:CGAffineTransformMakeTranslation(translation.width,
                                                      translation.height)];

// apply it
self.myLayer.path = path;