StackOverflow2013

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copied!<p>Brad Larson pointed me down the right road with his suggestion to put the <code>UIImageView</code> inside a <code>UIScrollView</code>.</p> <p>In the end I put the <code>UIImageView</code> inside of a <code>UIScrollView</code>, and set the scrollView's <code>contentSize</code> <strong>and</strong> the <code>imageView</code>'s bounds to be the same size as the image in the UIImage:</p> <pre><code>UIImage* image = imageView.image; imageView.bounds = CGRectMake(0, 0, image.size.width, image.size.height); scrollView.contentSize = image.size; </code></pre> <p>Then, I can animate the scrollView's <code>contentOffset</code> to achieve a nice panning effect:</p> <pre><code>[UIView beginAnimations:@"pan" context:nil]; [UIView setAnimationDuration:animationDuration]; scrollView.contentOffset = newRect.origin; [UIView commitAnimations]; </code></pre> <p>In my particular case, I'm panning to a random space in the image. In order to find a proper rect to pan <strong>to</strong> and a proper duration to get a nice constant speed, I use the following:</p> <pre><code>UIImage* image = imageView.image; float xNewOrigin = [TCBRandom randomIntLessThan:image.size.width - scrollView.bounds.size.width]; float yNewOrigin = [TCBRandom randomIntLessThan:image.size.height - scrollView.bounds.size.height]; CGRect oldRect = scrollView.bounds; CGRect newRect = CGRectMake( xNewOrigin, yNewOrigin, scrollView.bounds.size.width, scrollView.bounds.size.height); float xDistance = fabs(xNewOrigin - oldRect.origin.x); float yDistance = fabs(yNewOrigin - oldRect.origin.y); float hDistance = sqrtf(powf(xDistance, 2) + powf(yDistance, 2)); float hDistanceInPixels = hDistance; float animationDuration = hDistanceInPixels / speedInPixelsPerSecond; </code></pre> <p>I'm using a <code>speedInPixelsPerSecond</code> of <code>10.0f</code>, but other applications might want to use a different value.</p>

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