BCGControlBar Pro for MFC
CBCGPChartData CBCGPChartVisualObject::ChartDataFromScreenPoint ( const CBCGPPoint pt,
CBCGPChartAxis::RoundType  roundType,
BOOL  bUseSelectionTypeForReturn = FALSE,
BOOL  bIsStart = TRUE 
) const

Given a screen point returns a chart data.

You can use this method to convert screen coordinates (the point should be given in client coordinates of parent control) to Chart coordinates (values on related axes).

Alternatively, call CBCGPChartAxis::ValueFromPoint.

ptA point in client coordinates.
roundTypeType of the rounding operation. Can be one of the: RT_EXACT, RT_FLOOR, RT_CEIL or RT_ROUND
bUseSelectionTypeForReturnTRUE to use selection type for return.
bIsStartSpecifies how to round the returned value; TRUE - use "floor" to round the value; FALSE - use "ceil" to round the value.
A CBCGPChartData object, whose components are set according to values on axes, which contain the specified point ("contain" means that the point lays within a rectangle formed by axes). The values are placed in the internal array at indexes corresponding to axes IDs.