Visible Min and Max Value Demo for Amibroker (AFL)

_SECTION_BEGIN("Visible Max and Min Value Demo");
// Demo of 2 fuctions I wrote, which will find the Maximum and Minimum value in the visible horizontal chart area.
// Can be used for many different reasons and this is only an example. Inpiration came from several different codes
// I have seen, but can't at this moment find out who created them. Thanks anyway!!!
// I an new to AFL programming and this could probably be achieved in an easier way AND if so, please let me know.

Plot( C, "Close", ParamColor("Color", colorBlack ), styleNoTitle |
ParamStyle("Style") | GetPriceStyle() ); 

function VisibleMaxValue(Value)
{
 BI	= BarIndex();
 FirstVisibleBarIndex = Status("FirstvisiblebarIndex");
 FirstVisibleBar = FirstVisibleBarIndex == BI;
 HighestVisibleValue = HighestSince(FirstVisibleBar, Value);
 LastVisibleBarIndex = Status("LastvisiblebarIndex");
 BlankBars	= SelectedValue(LastVisibleBarIndex - BI);
 LastVisibleBar = LastVisibleBarIndex == BI + BlankBars;
 MaxValue 	= LastValue(ValueWhen(Lastvisiblebar, HighestVisibleValue));
 return MaxValue;
}

function VisibleMinValue(Value)
{
 BI	= BarIndex();
 FirstVisibleBarIndex = Status("FirstvisiblebarIndex");
 FirstVisibleBar = FirstVisibleBarIndex == BI;
 LowestVisibleValue	= LowestSince(FirstVisibleBar, Value);
 LastVisibleBarIndex	= Status("LastvisiblebarIndex");
 BlankBars	= SelectedValue(LastVisibleBarIndex - BI);
 LastVisibleBar = LastVisibleBarIndex == BI + BlankBars;
 MinValue 	= LastValue(ValueWhen(Lastvisiblebar, LowestVisibleValue));
 return MinValue;
}

Plot(VisibleMaxValue(High), "", colorGreen, 0);
Plot(VisibleMinValue(Low), "", colorRed, 0);

_SECTION_END();