CALayer content goes out of bounds - iOS

Question

I am trying to implement camera zoom using CGAffinetransform. Transform is fine, but when I scale it to a bigger size, it goes out of the frame I have assigned to the AVCaptureVideoPreviewLayer. I tried setting masksToBounds property to YES but it didn't help.

Can I contain it within its frame?

Edit:
What I want is that I can specify a specific area for the camera preview layer, if I apply scaling transform to it, (i.e., frame of preview layer gets expanded), the part of the layer outside of the specified area gets clipped.

Solution 1

You should put the layer you are scaling inside of another layer and mask that one instead (the superlayer). The same thing works with views.

I.e. You have two views / layers: clippingView and scalingView where scalingView is the subview of clippingView and clippingView is the view that actually clips to it's bounds.

[clippingView addSubview:scalingView];
clippingView.clipsToBounds = YES;

or using layers

[clippingLayer addSublayer:scalingLayer];
clippingLayer.masksToBounds = YES;

Solution 2

You guys are all partially right I found but I wanted to clarify.

Lets say we added something like AVCaptureVideoPreviewLayer to the view via [self.view.layer addSublayer:previewLayer]

1. [self clipsToBounds] does NOTHING until you are telling its primary layer to mask to bounds. [self.view.layer masksToBounds];

2. Just because your view has a frame and so does its layers DOES NOT MEAN IT HAS BOUNDS. If it doesnt have bounds then there is nothing to mask to. So do this self.view.layer.bounds = self.view.frame;

So heres it all together..keep in mind I did this in my own UIView class so I dont need to call self.view.

previewLayer.bounds = self.frame;
self.layer.bounds = self.frame;

self.layer.masksToBounds = YES;
previewLayer.masksToBounds = YES;

[self setBounds:self.frame];
[self clipsToBounds];

Comments

[neeraj]

I tried adding a separate view, (UIImageView because of some reason, but that shouldn't matter I suppose) and added a sublayer as the previewLayer which I was setting as the subLayer of self.view.layer. I set masksToBounds' as YES` but still it goes out of bounds

[neeraj]

What I did was, I made a view, with the frame that I wanted the preview layer to be in. and i set its property clipsToBounds to YES. That was all. Doc says that all the content of the view will lie inside the specified frame if this property is set to Yes. Actually I never came across the property before now.

[David Rönnqvist]

Any reason in particular for changing the accepted answer? You are basically saying the same thing as I am.

[neeraj]

1) Your answer was not the accepted answer before this, probably because I didn't understand it at that time. Confused between layers and views. 2) Yesterday I looked at my answer, and saw that there was no accepted answer, so I accepted my own...

[neeraj]

But now I see that yours was accepted. So, a mistake has been done.

[Nathan Kellert]

So is that all you had to change. Im having the exact same problem. the layer gets larger than the frame itself. I setup a NSLog to verify that the views fram itself wasnt getting larger. even though I have clipsToBounds on the view set to yes, and maskstobounds set to yes on the preview layer...the preview layer is still going outside.

[Kunal Shrivastava]

This is exactly what I was looking for. Even I have a custom UIView and I want to show a camera using AVFoundation. Thanks!