content size of UIScrollView

问题:

I have a UIScrollView in which I've set the contentSize to the size of the screen initially. So does this mean that if I have an UIImageView inside the scroll view then it can't zoom bigger than the contentSize I've set?

Because I initially have a UIScrollView with a contentSize of the phone's dimension and when I zoom into an image, it does it just fine (I can see the contentSize grows bigger as I zoom in) but when I adjust it manually it can't. Why is this?

I think when I initially initialize the UIScrollView frame, the content size will be set to the frame's size, however it can grow dynamically as I zoom in. However when I try to set the contentSize, it seems that now it's fixed. The reason why I am asking this is because I have a UIImageView inside a UIScrollView, when I zoom in on the image and I rotate the image, I want the contentSize to reset. Question is how do I reset this?

回答1:

The zoom level is set by the zoomScale property of the UIScrollView. Its maximum and minimum is set by maximumZoomScale and minimumZoomScale respectively.

If you're trying to set the zoom by setting the contentSize then you're doing it wrong. The contentSize should be set as if the zoom scale was 1.0 and then you'd just set the zoomScale property to be what you wanted so for example 2.0 if you wanted it zoomed in to 200%.

You're probably seeing contentSize change as you zoom because I think the scroll view reports it scaled to the current zoom scale.