An MFC Curve Control

• Download source files - 14.3 Kb
• Download demo project - 45.2 Kb

Introduction

• Derived from CWnd, easy to use
• Fits width and height of drawing rect
• Zooming in and out
• Mouse coordinates tracing
• Single/multiple selected by clicking mouse button
• Cross-line tracing mouse
• Add or delete a point of a curve by clicking mouse button
• Edit vertical value of a point of a curve by moving mouse with button down
• Easy to move, shift or mirror one curve
• Notify control�s owner when curve changing
• Owner determines whether to modify curve data by return values of message handle functions
• Unicode support
• Compiles under Windows 2000, VC 6.0 with warning level 4

Background

Recently, I wanted to visualize data in one of my applications. I had searched from Internet and downloaded some curve controls. Most of them are beautiful and work well, but none works as I want it to be. After reading source code of some controls, I decided to develop one curve control which would meet my application�s requirements.

Classes

CCurve

CCurve class, derived from CObject is used to store data and curve properties. It does not perform data adding or deleting.

• void ShowCurve(BOOL bShow = TRUE);
• BOOL IsVisible();

  Sets/gets visualization.

• void Select(BOOL bSelect = TRUE);
• BOOL IsSelected

  Sets/gets selected.

• BOOL SetCurveName(CString& strName);
• CString GetCurveName();

  Sets/gets curve name.

• void SetCurveColor(COLORREF color);
• COLORREF GetCurveColor();

  Sets/gets curve line color.

• void SetCurveStyle(int iStyle);
• int GetCurveStyle();

  Sets/gets curve line style.

• void SetCurveWidth(int nWidth);
• int GetCurveWidth();

  Sets/gets curve line width.

• float Distance(const CPoint& pt1, const CPoint& pt2);

  Gets distance between two points.

• BOOL IsPointNearCurve(const CPoint& point, int& iIndex);

  Whether the point is near the curve.

CCurveCtrl

• BOOL Create(const RECT& rect, CWnd* parent, UINT nID,DWORD dwStyle = WS_CHILD | WS_BORDER | WS_TABSTOP | WS_VISIBLE);

  Creates control, where rect is the dimensions. Refer to MSDN.

• int AddCurve(const CString& strName, COLORREF color = RGB(0, 0, 0), int iStyle = PS_SOLID, int nWidth = 1);

  Adds one curve to control.

• BOOL AddData(const CString& strName, float fHori, float fVert);
• BOOL AddData(CCurve* pCurve, float fHori, float fVert);

  Adds data to a curve by index or object pointer.

• BOOL AddCurveData(const CString& strName, const CArray< float, float >& ArrHori, const CArray< float, float >& ArrVert);

  Adds one curve and data at the same time.

• CCurve* GetCurve(int iIndex);
• CCurve* GetCurve(const CString& strName);

  Gets a curve object�s pointer by its index in CCurveCtrl or its name.

• int GetIndex(const CCurve* pCurve);

  Gets a curve�s index in CCurveCtrl by pointer.

• BOOL Remove(int index);
• BOOL Remove(const CString& strName);
• void RemoveAll();

  Removes a curve or all of the curves in CCurveCtrl.

• int GetCurveCount();

  Gets total count of curves.

• int GetSelectedCount();

  Gets count of selected curves.

• void Move(BOOL bLeft);
• void MovePage(BOOL bLeft);

  Moves all curves and coordinate scales left or right (will not modify data).

• void CurveLeft(CCurve* pCurve, float fLen); void CurveRight(CCurve* pCurve, float fLen);

  Shifts a curve left or right (will modify data of the curve).

• void MirrorHori(CCurve* pCurve, float fMid);

  Mirrors a curve in horizontal.

• void MirrorVert(CCurve* pCurve, float fMid);

  Mirrors a curve in vertical.

• void Restore();

  Shows all points of all curves.

• BOOL Zoom(BOOL bIn);

  Zooms in (bIn: TRUE) or zooms out (bIn: FALSE).

• void SetHoriLabel(CString& str);
• CString GetHoriLabel();

  Sets/gets horizontal label.

• void SetVertLabel(CString& str);
• CString GetVertLabel();

  Sets/gets vertical label.

• void ShowCross(BOOL bShow);
• BOOL IsShowCross();

  Whether to show cross lines.

• void SetMargin(const CRect& rect);
• CRect GetMargin();

  Sets/gets margin left to show title, etc.

• void EnableEdit(BOOL bEdit);
• BOOL CanEditCurve();

  Whether can edit curve data by using mouse.

• void SetGridLineStyle(int iStyle);
• int GetGridLineStyle();

  Sets/gets style of grid line in background.

Notifications

Following notify messages will be sent to control�s owner window (parent or not) if curve selected/ deselected or data modified by mouse operation:

• CVN_MVALUE_ADD - a point added to curve.
• CVN_MVALUE_CHANG - Y value of a point changing.
• CVN_MVALUE_DELETE - a point deleted.
• CVN_CURVE_SELECTED - a curve is selected.
• CVN_CURVE_CANCELSELECT - a curve is deselected.
• CVN_CURVE_SELECTNONE - deselected all curves.

Struct

typedef struct tagNM_CURVECTRL {
       NMHDR  hdr;      // curve object pointer

       void*  pCurve;   // curve object pointer

       int    iIndex;                                   
       float  fHori;    // horizontal value where cursor is

       float  fVert;    // vertical value where cursor is

} NM_CURVECTRL;

Note the iIndex member: it is the index of the point in the curve if the message sent to owner is CVN_MVALUE_ADD, CVN_MVALUE_CHANGE or CVN_MVALUE_DELETE; it is the index of the curve in CCurveCtrl if the message sent to owner is CVN_CURVE_SELECTED, CVN_CURVE_CANCELSELECT or CVN_CURVE_SELECTNONE.

Usage

Following steps demonstrate how to use CCurveCtrl in a dialog-based application:

1. Add curvectrl.h and curvectrl.cpp into your project;
2. Add a CCurveCtrl pointer member to your CDialog class:

   CCurveCtrl*  m_pCurveCtrl;

   And also add include statement:

   #include �CurveCtrl.h�

3. Set m_pCurveCtrl as NULL in your dialog construction functions:

   m_pCurveCtrl = NULL;

   Add control�s resource ID to your resource.h file, such as:

   #define ID_CURVE_CONTROL   9999

   In your CDialog::OnInitDialog(), add statements as following:

   if (NULL == m_pCurveCtrl)
   {
       m_pCurveCtrl = new CCurveCtrl;
       m_pCurveCtrl->Create(CRect(10, 10, 200, 200),    
                            this, 
                            ID_CURVE_CONTROL);    // resorce ID
   
                            m_pCurveCtrl->SetMargin(CRect(70, 50, 50, 50));
   }

4. Add one curve and data as following:

   CString  strName(TestOne);
   m_pCurveCtrl->AddCurve(strName, RGB(255, 0, 0));
   
   for (float f = 0.0f; f < 6.28f; f += 0.1f)
   {
       m_pCurveCtrl->AddData(strTitle, 
                            (m_nCurveCount) * f, 
                            100.f * float(sin(f)));
   }
   m_pCurveCtrl->Invalidate();

   If you want to add/delete or edit points with mouse operation, you must call:

   m_pCurveCtrl->EnableEdit(TRUE);

   Control�s owner will receive notify message, and if the return values of the messages is not 0 (>0 or <0), the edit or selection /deselection attempts will be rejected.

   For example, to handle the message of CVN_MVALUE_CHANG, add a handler in your dialog source file: 

   BEGIN_MESSAGE_MAP(CTestCurveDlg, CDialog)
            ... ...
   ON_NOTIFY(CVN_MVALUE_CHANG, ID_CURVE_CONTROL, OnCurveMouseModify)
   END_MESSAGE_MAP()
    
   // message handle function
   
   void CTestCurveDlg::OnCurveMouseModify(NMHDR *pNotifyStruct, LRESULT* pResult)
   {
       NM_CURVECTRL* pItem = (NM_CURVECTRL*)pNotifyStruct;
       CCurve* pCurve = (CCurve*)pItem->pCurve;
       CString str;
       str.Format("%s: index: %d, %.1f, %.1f", 
                           pCurve->GetCurveName(), 
                           pItem->iIndex, 
                           pItem->fHori, 
                           pItem->fVert);
       TRACE(str);
       // Uncomment following statement if to reject changing
   
       // *pResult = 1;
   
   }

Refer to sample application TestCurve if you want more information.

History

• V1.0, 19 September 2004

  CCurve, CCurveCtrl first released.