Zoom out on large UIImageView within an UIScrollView

Case: I have a simple piece of code for displaying/zooming/scrolling a large image in an UIImageView->UIScrollView. In this UIScrollView content I want to place buttons to create clickable areas.

Issue: When I zoom in the quality remains proper but, when I zoom out to the highest posible level than the image is getting dotted and some lines aren't visible anymore.

Tried:开发者_StackOverflow I tried to regenerate the UIImage with Interpolation Quality on kCGInterpolationHigh and tried to change the size of the image after every zoom change. As you might aspect, no results jet.

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I suggest you use a CATiledLayer as the backing layer, as demonstrated by Apple's PhotoScroller sample app. This allows you to prebuild the scaled versions, meaning you can precisely control the interpolation quality with Photoshop/ImageMagick/GIMP etc, rather than relying on UIScrollView's built-in scaling.