iPhone iOS: How to dynamically move around/resize images on top of an image background?

I am interested in developing an app that allows a user to do the following:

1. Set a background image
2. Add images on top of the background image
3. Allow user to move the images around by touching and dragging
4. Allow use开发者_开发技巧r to rotate/scale these images

Specifically, I am interested in knowing how to detect a touch in one of the images that get added on top of the background image, how to detect which image is being touched so that it can be manipulated, maintain z-order, etc.

What's the best way to go about doing this? Any sample code out there?

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I suggest you tackle this in bite-sized chunks:

1. Display a single image on the screen.
2. Move it with one finger.
3. Zoom it with two fingers (use a gesture recogniser).
4. Rotate it with two fingers.
5. Add a second image.

It should be quite easy to find tutorials for each of these elements. It's your job to put it all together.

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You can find the view which touched like

//backgroundImageView should be declared in header file 
if([touch view] != backgroundImageView && [[touch view] isKindOfClass:[UIImageView class]]) {
    //You have touched imageView on top of background imageview
}

I hope now you have got an "IDEA".

Also search on google and stackoverflow you will find many samples about it.