I am trying to get a UIView to clip to subviews but not entirely. I mean like an alpha change, outside the bounds
Edit:
I want this to be like the keynote mask feature for an image in the iPad.
You aren't going to be able to change alpha outside the bounds of a view, as you indicate. But a better solution would be:
Create a new view that extends the entire area. Set the alpha of this view to the desired value. Add another view inside this view, set clipsToBounds = YES on this view.
You can achieve this by using 2 views, but I don't think you can with 1.
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I have an app that allows a user to drag views onto the screen in multiple orientations. So lets say i'm in portrait mode and my superview is 768x1024. Lets say I drag 10 different items onto that superview. These items are scaled, rotated, etc. Then I rotate the device and my superview shrinks down to 576x768. How do I get all of my subviews to maintain their position and transform relative to the new smaller size? So in essence my superview and all of its subviews should look exactly as they did while in portrait, except everything has been scaled down.
And also, what if im in landscape and everything is "shrunk" down and then I drag another view on and shrink it down to fit well. I would need that new view to scale up in proper place and size when the device is rotated back into portrait
The easiest thing to do here is to use the transform property of your view. In this case, you'd prevent the view from auto-resizing on rotation, and use something like your view controller's willAnimateRotationToInterfaceOrientation:duration: method to set a transform on your superview. You can create a transform with CGAffineTransformMakeScale that will scale up or down all of your content; you'll probably want one for landscape and just use a nil transform for portrait (or vice-versa).
This will complicate dragging new views into your superview, since it's transformed, but once you've got views in there, they should behave correctly when resizing. For new views, you'll have to compute (perhaps using convertRect:fromView: method of UIView) what a rect will be once you add a new subview.
You can also override your view's layoutSubviews() directly and assign your subview's transforms based on your view's dimension. This way, you can still get the benefits of using Auto Layout with your view and potentially other sibling UI items, while you customize subview's frames and/or transforms manually without Auto Layout.
I am displaying a big image in CATiledLAyer.
Now i want to draw a line between two points where the user touches on that image.
Would that be possible ?? , if so can you outline me the way to accomplish it ??
Thanks,
Ratna
I did something similar for an app a while back. The strategy I used was to place another view on top of the view with the tiles. Then set your self up as a UIScrollViewDelegate and everytime the tiled view scrolls or zooms, recalculate where the overlayed objects need to be. Just read the contentOffset value and the zoomScale and you should have what you need to correctly figure out where your overlay needs to be positioned. You will also have to make sure that touches are correctly reaching the tile view if they have to pass through your overlay view.
I've learned that the best way to get graceful rotation is to set the auto rotation mask on the view that you want resize or move. This works fine if you're using SDK views like UILabel, but if you have your own custom view that uses the drawRect method it doesn't rotate as gracefully. In fact the only thing that happens is that it stretches whatever you drew in drawRect.
I've tried redrawing both before and after the rotation, but it doesn't give me that smooth rotation.
I looked at a UITextField auto rotating (flexible width) in slow motion and it follows the edge perfectly during the rotation. That is what I want my view to do, so how do I do that? My views jump to the right position either before or after the rotation.
The following line will make your UIView stretch the middle pixel only. If this is not your desired behavior I suggest you read the documentation for contentStretch to learn how to manipulate the values of the CGRect.
[self setContentStretch:CGRectMake(0.5, 0.5, 0.0, 0.0)];
I would guess that the UITextField you're looking at has at least three subviews, one displaying the left cap of the field's border, one displaying the right cap, and one displaying the middle, with autoresizing masks of "flexible right margin", "flexible left margin", and "flexible width", respectively. If you set up your custom view something like that, and make sure its autoresizesSubviews property is set to YES, then you should get the same smooth resize that the text field does.
so I have a UIImageView in a UIView but when I run it in the iPhone Simulator, the image goes beyond the boundaries of the UIView. What's wrong...?
Have a look at the clipsToBounds property of UIView. If you set this to YES on your view the UIImageView shouldn't extend outside of that view any more.
You may also benefit from using the Content Mode property in which you can specify how the content is drawn to fit the view. You can set it to fill, fit-to-scale, etc.
I created a UIView xib in Interface Builder and tried everything I could to indicate that the UIView should center itself, anchor itself at center, orient itself in central coordinates, etc. etc.
But whenever I add it as a subview in code, I also have to programmatically set its frame up with CGRectMake() or else it will always add to the top-left of its parent. The math to reframe it is pointless and ugly, so I presume I'm just not twiddling a bit in the IB inspector correctly.
Can anyone confirm this is possible, and if so, what I need to do in IB to accomplish this?
Why don't you just set .center of the subview just added, to be the point created by halving the width and height of the superview?
Either that or define the rectangle that view is going into with IB (I'm imagining a container view) and simply set the frame of the view you are adding to containerView.bounds (bounds is a position independent value and so x,y will be 0 while size will equal the container size.
Centering but maintaining size isn't possible in IB. Centering but maintaining margins to its superview is though.
You will have to override the layoutSubviews message or simply keep the calculation code you wrote.