I want to zoom in and out a UIVIew on to specific point something similer effect to focus + zoom in. I don't want to use UISCrollView. What is the right approach to do this if anyone could suggest.
Thanks
The right approach is to use a scroll view. If you don't want to use a scroll view, though, you can use a tiled layer. Bill Dudney has an example of that here: http://bill.dudney.net/roller/objc/entry/tiledlayer_on_the_iphone
Why don't you want to use a scroll view?
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I have a view based application. I have to add features like pinch zoom and double tap to zoom the page(UIView) in the iOS application. Its easy to zoom a UIScrollview.
I should create a framework which has the option to pan and zoom the entire app. How do a achieve to zoom a view based application? I welcome your ideas!
The best way to do it, is to put the entire app components in one scrollview and use the zooming of the control.
The other way which is not as stable as the first one, is to scale all objects inside the UIVIEW larger or smaller depending on the pinch zoom, but keep in mind that scaling will affect the look of the entire application, so you need to adjust the position of each object accordingly.
You can create your own zoom functionalities in a UIView by using UIGestureRecognizer and CALayer transform property. Ex. scaling and change the anchorPoint base on the focus point.
I've seen iOS apps that allow users to scroll around a view that is larger than the screen itself, without seeming to implement a UIScrollView mechanic. So for example, the actual image displayed on the screen is double the width of the screen, and the user can pan left and right to view all the content. Is this just a case of making the ViewController's width twice that of the screen and allowing some kind of panning via gesture recognizers? With what I'm trying to do, it seems like this would be easier that implementing a UIScrollView...
Implementing scrollview is much easier than handling pan gesture, when Apple has given built-in functionality then why you do not want to use it?
You can either use UIPangestureRecognizer or UIscrollview. The Latter option is very simple.
I am creating a graphing calculator application in OpenGL on iOS, and I would like to implement pinch zooming that works like the google maps application or uiscrollview zooming. I'm pretty sure I can't use a uiscrollview because the content of the graph is being generated dynamically.
Implementing zooming where the center of the screen is assumed to be the center of the zoom is easy, but in other cases it is not obvious to me how its being implemented. Can anyone point me in the right direction?
The view that does your custom drawing should be capable of drawing at a certain scale. When your user zooms in or out of the scroll view, send the appropriate zoom factor and let the view redraw itself. The changing bounds is not a problem. The scroll view adjusts its bounds as you pan inside, so its subviews shouldn't have any concern over the bounds of the scroll view.
Of course, you'll probably have to consider performance. For example, it may be too slow to redraw the graph at every frame as a user zooms. Instead, you may only want to redraw when the user stops zooming, which is what Maps.app does.
There are many other considerations for this problem, but that would be where I would start.
EDIT: Ah, I overlooked the OpenGL aspect. Still, with a GL layer-backed view, you still should be able to make the appropriate translations based on both the current zoom factor as well as the scroll view's bounds.
I need to zoom an image in iphone...while the user double clicks on the image it will be zoomed in and on the next click it will be zoomed out....Can anybody direct me to how to do this???
You would probably have to use the size property of UIImage, triggered by UIImageView's touchesBegan method.
You can also use animations if you want the zoom effect to be smooth.
Another option could be to place your UIImageView inside a UIScrollView, or use a UIWebView.
Also, I suggest you take a look at the Three20 project. I think TTPhotoView supports zooming.
If you want to zoom and scroll your view, you need a UIScrollView. Tricking it to do what you want used to be very hard, however the problem of programmatic zooming of UIScrollView is now solved.
I have a described how to do it, created ZoomScrollView class (a drop-in subclass of UIScrollView) to encapsulate the solution and provided a working example at github.com/andreyvit/ScrollingMadness/ (the README contains a long description of two UIScrollView tricks and the reasoning behind them).
I'm working on an iPhone game, and trying to use a UIScrollView to display some icons, which I then want to enable the user to drag off the bar being scrolled, onto another view (basically, dragging them from their hand into play on the game board). The problem is that the UIScrollView clips everything outside it's own bounds.
Here is a picture of what I'm trying to do:
Functionally, it actually works, in that you can drag the icons up to the white board fine...but you can't see them as you are dragging...which is not acceptable.
Does anyone know if you can temporarily disable the clipping that a scroll view does, or is there some way to get around it? Hacky or not, I would really like to make it happen.
Does anyone have any other possible solutions for this? Or maybe any alternate approaches? I've considered if maybe a page view might work, but haven't tried it yet...and it's not at all as good of a solution as the scroll view.
Worst case I can just go back to not having the bar scrollable, but that really puts a damper on some of my game mechanics, and I'm really not too excited about that.
I think you're looking for the clipsToBounds property of UIView. I've used it successfully with UIScrollView:
scrollView.clipsToBounds = NO;
However, the dragging you want to do from the scroll view to the game view may require you to remove the icon view from the scroll view, place it in the superview at a position corresponding to its visible position within the scroll view (calculated using the scroll view's origin and content offset), and have that track the user's finger movements. On a release of the touch, either drop it on the game view at the proper position or return it to the scroll view.
I'm not 100% sure I understand the question but I think you should look into the z order of the scrollview and the whiteboard. It may be that the drag is just going behind the whiteboard.
Failing that, it would be useful to see all the bounds of your view heirarchy.
I also think a better solution allround might be to create a "sprite" to animate underneath the players finger - you could offset the drawpoint of the sprite from the touchlocation so that the player can see what they are dragging.