Scale a UIView automatically on orientation change to scale proportionaltely to fit in parent view

Question

A UIImage view set to "Aspect Fit" will automatically dynamically scale it's image to fit within the current bounds of the UIUmageView, while maintaining the image's proportions. A UIView set to "Aspect Fit" does not seem to have this same effect on it's sub-views.

I have tried to set the parent view via code, with the code below, and tried several variations on the auto-resizing mask ( I am not using auto layout). Am I missing something obvious, or do I need to write a little code to compute the right scale for my sub-view based on the current size of the parent view?

[self.view setContentMode:UIViewContentModeScaleAspectFit];

score 6 · Answer 1 · answered Jan 01 '13 at 15:01

From the documentation:

The content mode specifies how the cached bitmap of the view’s layer is adjusted when the view’s bounds change.

For an image view, this is talking about the image. For a view that draws its content, this is talking about the drawn content. It does not affect the layout of subviews.

You need to look at the autoresizing masks in place on the subviews. Content mode is a red herring here. If you can't achieve the layout you need using autoresizing masks, then you need to implement layoutSubviews and calculate the subview positions and frames manually.

yeah thanks, I think I will have to do it manually then. Seems like not such a big thing, but also it get's a bit complicated, as I have been working on it for a bit now. I just wanted to make sure I wasn't missing a method or other class that would assist. — OWolf, Jan 01 '13 at 15:36

score 2 · Answer 2 · edited May 23 '17 at 11:59

2

Content modes do not affect the subviews of the view.
You would use auto-resizing masks to determine how the subviews are laid out.
If that is not sufficient, you may want to implement layoutSubviews

Referenced from: https://stackoverflow.com/a/14111480/1374512

Other useful info on layoutSubviews: https://stackoverflow.com/a/5330162/1374512

edited May 23 '17 at 11:59

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answered Mar 28 '13 at 06:33

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score 1 · Answer 3 · edited May 23 '17 at 12:15

How about this :

 self.autoresizingMask = UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth;

Or you can try this :

// horizontal 
   childView.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin |  UIViewAutoresizingFlexibleRightMargin;

// vertical 
   childView.autoresizingMask = UIViewAutoresizingFlexibleTopMargin | UIViewAutoresizingFlexibleBottomMargin;

// both 
   childView.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleRightMargin | UIViewAutoresizingFlexibleTopMargin | UIViewAutoresizingFlexibleBottomMargin;

If you want any further Reference, I think these are two beautiful Questions :

1) Autoresizing masks programmatically

2) UIView and AutoresizingMask ignored

thanks a lot! but from trying these, seems that none of these options scales the sub-view to fit the bounds of the parent view while maintaining the proportionality of the sub-view. — OWolf, Jan 01 '13 at 14:15

score 0 · Accepted Answer · answered Jan 01 '13 at 16:40

I've been playing around with it. This is incomplete, just handles the portrait subview scaling, but works ok so far.

if (self.view.bounds.size.width < self.view.bounds.size.height) {
    NSLog(@"view is portrait");
    if (_sview.frame.size.width < _sview.frame.size.height) {
        NSLog(@"subview is portrait");
        [UIView animateWithDuration:0.1
                         animations:^{
                             _sview.transform = CGAffineTransformScale(CGAffineTransformIdentity, 1.0, 1.0);
                         }];
    } else {
        NSLog(@"subview is landscape");
    }
} else {
    NSLog(@"landscape");
    if (_sview.frame.size.width < _sview.frame.size.height) {
        [UIView animateWithDuration:0.1
                         animations:^{
                             _sview.transform = CGAffineTransformScale(CGAffineTransformIdentity, 0.65, 0.65);
                         }];
    } else {
        NSLog(@"subview is landscape");
    }

}

Scale a UIView automatically on orientation change to scale proportionaltely to fit in parent view

4 Answers4