Graph Animation

Wednesday Feb 27th 2002 by Salick Cogan.
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CGraph is a very simple class for drawing animated graph. The interface includes a several easy to use functions.

Environment: VC6 WIN 9x/2k

For some time I've been wanting to imitate the 'CPU Usage' Graph in win 2k, so I finally did.
CGraph is a very simple class for drawing animated graph. The interface includes a few simply functions:

CGraph(int x, int y, int width, int height);
Constructor which defines the size of the graph.

void SetLineColor(COLORREF cl);
Sets the color of graph line}

void SetLinesColor(COLORREF cl);
Sets the color of the axes

void SetRange(int start, int end);
Sets the range values of the graph}

void SetBK(COLORREF cl);
Sets the background color of the graph}

void DrawGraph(CDC *pDC);
Draws the graph

BOOL AddPoint(CDC *pDC, int y);
Adds a point with value 'y' to the graph and draws it
Returns 'TRUE' if the point is llegal, 'FALSE' if it's not.

int GetRange()
Get the range of values in the graph

//The tested app is a non doc/view MFC App

CGraph *m_Graph;
// m_Graph is a member variable of m_wndView 
// which is a member of CMainFrame

void CMainFrame::OnViewGraph() 
{
  CClientDC dc(m_wndView.FromHandle(m_wndView.GetSafeHwnd()));

  m_wndView.m_Graph = new CGraph(3, 3, 400, 400);

  m_wndView.m_Graph->SetBK(RGB(0,0,0));
  m_wndView.m_Graph->SetRange(0, 100);
  m_wndView.m_Graph->SetLinesColor(RGB(0, 255, 0));
  m_wndView.m_Graph->SetLineColor(RGB(255,0,0));
	
  m_wndView.m_Graph->DrawGraph(&dc);

  m_wndView.m_Graph->AddPoint(&dc, 40);
  m_wndView.m_Graph->AddPoint(&dc, 80);
  m_wndView.m_Graph->AddPoint(&dc, 23);
  m_wndView.m_Graph->AddPoint(&dc, 99);
  m_wndView.m_Graph->AddPoint(&dc, 40);
  m_wndView.m_Graph->AddPoint(&dc, 80);
  m_wndView.m_Graph->AddPoint(&dc, 23);
  m_wndView.m_Graph->AddPoint(&dc, 99);

  m_wndView.m_Graph->AddPoint(&dc, 40);
  m_wndView.m_Graph->AddPoint(&dc, 80);
  m_wndView.m_Graph->AddPoint(&dc, 23);
  m_wndView.m_Graph->AddPoint(&dc, 99);

  m_wndView.m_Graph->AddPoint(&dc, 40);
  m_wndView.m_Graph->AddPoint(&dc, 80);
  m_wndView.m_Graph->AddPoint(&dc, 23);
  m_wndView.m_Graph->AddPoint(&dc, 99);
	
  //Added the exact amount of points to fill the graph

  SetTimer(1, 500, 0);
  //Starts a timer which adds a random point every 500 ms.
}


void CMainFrame::OnTimer(UINT nIDEvent) 
{
  if (nIDEvent == 1)
  {
    CClientDC dc(m_wndView.FromHandle(m_wndView.GetSafeHwnd()));

    int rnd = rand() % m_wndView.m_Graph->GetRange();
    m_wndView.m_Graph->AddPoint(&dc, rnd);
  }
	
  CFrameWnd::OnTimer(nIDEvent);
}

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