@Override
    public boolean canScrollHorizontally(int direction) {
        if (getZoomLevel() <= 1.0) {
            return false;
        }
        final Viewport currentViewport = getCurrentViewport();
        final Viewport maximumViewport = getMaximumViewport();
        if (direction < 0) {
            return currentViewport.left > maximumViewport.left;
        } else {
            return currentViewport.right < maximumViewport.right;
        }
    }
When embedded in a ViewPager, this will be called in order to know if we can scroll.
If this returns true, the ViewPager will ignore the drag so that we can scroll our content.
If this return false, the ViewPager will assume we won't be able to scroll and will consume the drag

@param direction Amount of pixels being scrolled (x axis)
@return true if the chart can be scrolled (ie. zoomed and not against the edge of the chart)
hellocharts-library/src/lecho/lib/hellocharts/view/AbstractChartView.java