How to scroll and zoom in/out large images on iPhone?

Question

I have a large image, size around 30000 (w) x 6000 (h) pixels. You may consider it's like a big map. I assume I need to crop it up into smaller tiles. Questions:

• what are the right ViewControllers to use?
• (link) what is the tile strategy? (I put this in another question, as it's not iPhone specific)

Requirements:

• whole image (though cropped) can be scrolled up/down/left/right by swipes
• zoom in (up to pixel-to-pixel) out (down to screen-fit-by-height) by the 2-finger operation
• memory efficiency by lazy loading tiles

Bonus requirements:

• automatic scroll, say from left to right slowly and smoothly

Thanks!

Answer 1

Check out part 3 of Apple's ScrollViewSuite sample code for an example of how to do this.