#define ASKCOLOR RGB(255, 128, 128)
#define BIDCOLOR RGB(128, 255, 128)
#define POSDELTACOLOR RGB(32, 255, 32)
#define NEGDELTACOLOR RGB(255, 32, 32)


SCSFExport scsf_DeltaMomentum(SCStudyGraphRef sc) 
{ 
	SCSubgraphRef askVol 			= sc.Subgraph[0];
	SCSubgraphRef bidVol 			= sc.Subgraph[1];
	SCSubgraphRef deltaVol 			= sc.Subgraph[2];
	SCSubgraphRef deltaMomentum 	= sc.Subgraph[3];


	if (sc.SetDefaults) {
		sc.GraphName = "DeltaMomentum"; 
		sc.GraphRegion = 1; 
		sc.ScaleRangeType = SCALE_AUTO;
		sc.StudyDescription = "DeltaMomentum"; 


		sc.FreeDLL = 0; 

		sc.AutoLoop = 0; // Manual looping 

		askVol.Name = "Ask Volume";
		askVol.PrimaryColor = ASKCOLOR;
		askVol.DrawStyle = DRAWSTYLE_IGNORE;

		bidVol.Name = "Bid Volume";
		bidVol.PrimaryColor = BIDCOLOR;
		bidVol.DrawStyle = DRAWSTYLE_IGNORE;

		deltaVol.Name = "Delta";
		deltaVol.DrawStyle = DRAWSTYLE_IGNORE;


		deltaMomentum.Name = "Delta Momentum";
		deltaMomentum.PrimaryColor = POSDELTACOLOR;
		deltaMomentum.SecondaryColor = NEGDELTACOLOR;
		deltaMomentum.LineWidth = 2;
		deltaMomentum.DrawStyle = DRAWSTYLE_BAR;
		deltaMomentum.AutoColoring = AUTOCOLOR_POSNEG;
		return; 
	} 
	int ind = sc.UpdateStartIndex;	
	if (ind == 0)
	{
		askVol[ind] 	= sc.BaseDataIn[SC_ASKVOL][ind];
		bidVol[ind] 	= -sc.BaseDataIn[SC_BIDVOL][ind];
		deltaVol[ind]	= askVol[ind] + bidVol[ind];
		deltaMomentum[ind] = deltaVol[ind];
		++ind;
	}	
	for (; ind < sc.ArraySize; ++ind)
	{
		askVol[ind] 	= sc.BaseDataIn[SC_ASKVOL][ind];
		bidVol[ind] 	= -sc.BaseDataIn[SC_BIDVOL][ind];
		deltaVol[ind]	= askVol[ind] + bidVol[ind];
		if (deltaVol[ind] > 0) 
		{
			if (deltaMomentum[ind-1] >= 0)
			{
				deltaMomentum[ind] = deltaMomentum[ind-1] + deltaVol[ind];
			}
			else
			{
				deltaMomentum[ind] = deltaVol[ind];
			}
		}
		else if (deltaVol[ind] < 0)
		{
			if (deltaMomentum[ind-1] <= 0)
			{
				deltaMomentum[ind] = deltaMomentum[ind-1] + deltaVol[ind];
			}
			else
			{
				deltaMomentum[ind] = deltaVol[ind];
			}
		}
		else 
		{
			deltaMomentum[ind] = deltaMomentum[ind-1]; 
		}
	}
}