A 2D Graph Component With Zoom Capability

#pragma once
#include <Atlimage.h>

#define SAFE_DELETE(p) {if(p) delete [] p; p = 0;}
//---------------------------------------------------------------
template <typename DataType>
class CGraphDataSet
{
public:
	CGraphDataSet()
	{
		m_yDataSet.pData = NULL;
		m_xDataSet.pData = NULL;
		m_clr = RGB(0,255,0);
	};
	//divNo: graph divides to divNo slices
	//SubPlot: where new data will be ploted. an integer between 0 and divNo.
	void SetData(DataType* xData, DataType* yData, int nLen)
	{
		//ATLASSERT(xData);
		ATLASSERT(yData);
		DataType yMin = yData[0];
		DataType yMax = yData[0];
		DataType xMin = 0;
		DataType xMax = 0;
		if(xData == NULL)
		{
			xMin = 0; xMax = nLen;
			xData = new DataType[nLen];
			for(int i = 0; i < nLen; i++)
				xData[i] = i;
		}
		else
		{
			xMin = xMax = xData[0];
			for(int i = 1; i < nLen; i++)	
			{
				if(xData[i] > xMax)
					xMax = xData[i];
				else if(xData[i] < xMin)
					xMin = xData[i];
			}
		}
		for(int i = 1; i < nLen; i++)	
		{
			if(yData[i] > yMax)
				yMax = yData[i];
			else if(yData[i] < yMin)
				yMin = yData[i];
		}
		SetData(xData,yData,nLen,xMin,xMax,yMin,yMax);
	}

	void SetData(DataType* xData, DataType* yData, int nLen, 
		DataType xMin, DataType xMax, DataType yMin, DataType yMax)
	{
		if(m_xDataSet.pData)
			SAFE_DELETE(m_xDataSet.pData);
		if(m_yDataSet.pData)
			SAFE_DELETE(m_yDataSet.pData);

		m_xDataSet.pData = new DataType[nLen];
		m_yDataSet.pData = new DataType[nLen];
		
		memcpy(m_yDataSet.pData, yData, nLen*sizeof(DataType));
		m_yDataSet.size = nLen;
		m_yDataSet.Max = yMax;
		m_yDataSet.Min = yMin;

		memcpy(m_xDataSet.pData, xData, nLen*sizeof(DataType));
		m_xDataSet.size = nLen;
		m_xDataSet.Max = xMax;
		m_xDataSet.Min = xMin;
	};

	struct DataSet{
		DataType *pData;
		int size;
		double Max;
		double Min;
	};
	void Draw(HDC hdc, RECT &rc, int nType = 0, int divNo = 1, int SubPlot = 0)
	{
		ATLASSERT(hdc);
		ATLASSERT(divNo > 0);
		ATLASSERT(SubPlot > -1 && SubPlot < divNo);

		int H = rc.bottom- rc.top;
		int W = rc.right- rc.left;

		double dx = (double)W/((m_xDataSet.Max-m_xDataSet.Min) * divNo);

		int X0 = rc.left;
		int Y0 = rc.top;
		int x1 = 0, x2 = 0, y1 = 0, y2 = 0;
		if(nType == 0)//Normal graph
		{
			for(int i = 0; i < m_yDataSet.size-1; i++)
			{
				x1 = X0 + (W/(m_xDataSet.Max - m_xDataSet.Min))*(m_xDataSet.pData[i] - m_xDataSet.Min);
				x2 = X0 + (W/(m_xDataSet.Max - m_xDataSet.Min))*(m_xDataSet.pData[i+1] - m_xDataSet.Min);
				y1 = Y0 + H - (H/(m_yDataSet.Max - m_yDataSet.Min))*(m_yDataSet.pData[i] - m_yDataSet.Min);
				y2 = Y0 + H - (H/(m_yDataSet.Max - m_yDataSet.Min))*(m_yDataSet.pData[i+1] - m_yDataSet.Min);
				MoveToEx(hdc,x1,y1,0);
				LineTo(hdc,x2,y2);
			}
		}
		else if(nType == 1)//dot graph
		{
			for(int i = 0; i < m_yDataSet.size; i++)
			{
				x1 = X0 + (W/(m_xDataSet.Max - m_xDataSet.Min))*(m_xDataSet.pData[i] - m_xDataSet.Min);
				y1 = Y0 + H - (H/(m_yDataSet.Max - m_yDataSet.Min))*(m_yDataSet.pData[i] - m_yDataSet.Min);
				SetPixel(hdc,x1,y1,m_clr);
			}
		}
		else//if nType == 2 BarGraph 
		{
			int Y02 = Y0 + H - (H/(m_yDataSet.Max - m_yDataSet.Min))*(0 - m_yDataSet.Min);
			for(int i = 0; i < m_yDataSet.size; i++)
			{
				x1 = X0 + (W/(m_xDataSet.Max - m_xDataSet.Min))*(m_xDataSet.pData[i] - m_xDataSet.Min);
				y1 = Y0 + H - (H/(m_yDataSet.Max - m_yDataSet.Min))*(m_yDataSet.pData[i] - m_yDataSet.Min);
				MoveToEx(hdc, x1, Y02, 0);
				LineTo(hdc, x1, y1);
			}
		}
		return;
	}

	DataSet m_yDataSet,m_xDataSet;
	COLORREF m_clr;
};