@protocol SChartCrosshair <NSObject>
The chart’s crosshair interface - the chart will push ‘show’, ‘move’ and ‘hide’ events onto the crosshair, which should respond appropriately.
Instructs the crosshair to show itself in the chart at
pointInChart, which is in the chart’s coordinate space.
This method is called each time the chart wishes to make the crosshair visible, and is paired with a -hide call.
Instructs the crosshair to move itself in chart to the position
pointInChart, in the chart’s coordinate space.
This method is called every for frame of the crosshair’s movement, when the chart wishes to update the crosshair.
Instructs the crosshair to hide itself from view (and usually to removeFromSuperview)
This method is called by the chart when the crosshair should be dismissed, paired with the showAtPoint:inChart: call.
Returns a BOOL representing whether the crosshair is hidden.
func isHidden() -> Bool