Coreplot - selecting area below line
<p>I am using coreplot to draw a scatter plot like that:
<a href="https://i.stack.imgur.com/EJ13W.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/EJ13W.png" alt="enter image description here"></a></p>

<p>I use 4 different plots (as coloured) and create a "bar like" feeling by adding 0-value points at the beginning/end of each "bar".
I want to determine which bar was selected by the user and then change alphas of other plots.</p>

<p>I've tried using</p>

<pre><code>-(BOOL)plotSpace:(CPTPlotSpace *)space shouldHandlePointingDeviceDownEvent:(id)event atPoint:(CGPoint)point {
    //here I translate the selected point to Data points coordinates 
    //and check which of the plot sources has value &gt;0 (that means bar is visible)
    //and is closest to the selected point
}
</code></pre>

<p>This method works, but when I want to scroll the data, the method above is called as well.</p>

<p>There must be some easier solution to do that. Thanks.</p>