Reposition/resize UIBezierPath

Soc picture Soc · Dec 5, 2013 · Viewed 12k times · Source

I have a draggable view that has a mask layer on it. The mask layer has a UIBezierPath on it which makes an area on the view see-through/transparent(the effect that i want). My end goal is to change the position and size of the path(not the mask layer!) by passing a CGRect that is calculated based on the intersection of my view and another rectangle(Basically I want to hide the area that intersects).

1)How I create my mask and path(creates a see-through rectangle on my view):

self.maskLayer = [CAShapeLayer layer];
self.maskLayer.frame = self.contentView.bounds;

//default path rect
CGRect const rect = CGRectMake(CGRectGetMidX(self.contentView.bounds) ,
                                     CGRectGetMidY(self.contentView.bounds),
                                     50,50);


path = [UIBezierPath bezierPathWithRect:rect];

[path appendPath:[UIBezierPath bezierPathWithRect:self.contentView.frame]];

self.maskLayer.path = path.CGPath;

self.maskLayer.fillRule = kCAFillRuleEvenOdd;

self.contentView.layer.mask = self.maskLayer;

2) My problem is that I couldn't find a way to resize/reposition just the path. I searched online but couldn't find any solution.

This code is not working but is what I could think of:

//runs while the view is being dragged(using UIPanGestureRecognizer)
-(void)move{
 CGRect intersectedRect = CGRectIntersection(self.frame, self.productView.frame);
 path = [UIBezierPath bezierPathWithRect:intersectedRect];
[path appendPath:[UIBezierPath bezierPathWithRect:intersectedRect]];
[self.maskLayer setNeedsDisplay];
 }

How can I manipulate just the path of the masklayer in my move function? Thank you!

Answer

hfossli picture hfossli · Dec 5, 2013
// 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;