How to allow UIScrollView to scroll below content offset 0?
<p>I'm using <code>UIScrollView</code> to create recording timeline just like Voice Memo app. This is horizontal <code>scrollview's</code> frame at the beginning. I use <code>CAShapeLayer</code> to draw bars.</p>

<pre><code> scrlViewBars.frame = CGRectMake(0, scrlViewBars.frame.origin.y, SCREEN_WIDTH, 100);
    ....
 [shapeLayer setPath:[[UIBezierPath bezierPathWithRoundedRect:CGRectMake(0, 0, barWidth, barHeight) cornerRadius:2] CGPath]];
 [scrlViewBars.layer addSublayer:shapeLayer];
</code></pre>

<p>Recording starts and draws wave bars from beginning i.e wave bars are created from zero X position of <code>UIScrollView</code>. When bars will reach to the half of the screen, I start moving <code>UIScrollView</code> back by giving <code>contentSize</code> and <code>contentOffset</code>. So bars then will remain in centre after that just like Voice Memo app.</p>

<p>Everything works great except proper <code>UIScrollView</code> timeline. If the recording is small, <code>contentSize</code> will not be larger than screen width. So is it possible to <code>UIScrollView</code> to go below 0 <code>contentOffSet</code>? Because after recording is stopped, user can scroll timeline and starting content of recording should go till centre of the screen because there is a scrub bar at the centre which will not move and shows current recording time.</p>