CChartLegend类用来绘制每一个波形的描述信息，它处于该控件的区域，如下图所示： 

CChartLegend类的头文件。

#if !defined(AFX_CHARTLEGEND_H__CD72E5A0_8F52_472A_A611_C588F642080B__INCLUDED_)#define AFX_CHARTLEGEND_H__CD72E5A0_8F52_472A_A611_C588F642080B__INCLUDED_#if _MSC_VER > 1000#pragma once#endif // _MSC_VER > 1000#include "ChartObject.h"#include "ChartCtrl.h"#include "ChartString.h"class CChartSerie;class CChartLegend : public CChartObject  {    friend CChartCtrl;public:    void SetFont(int iPointSize, const TChartString& strFaceName);    CChartLegend(CChartCtrl* pParent);    virtual ~CChartLegend();    enum DockSide    {        dsDockRight,        dsDockLeft,        dsDockTop,        dsDockBottom    };    void DockLegend(DockSide dsSide);    void UndockLegend(int iLeftPos, int iTopPos);    void SetTransparent(bool bTransparent);      void SetHorizontalMode(bool bHorizontal);private:    void Draw(CDC* pDC);    void ClipArea(CRect& rcControl, CDC* pDC);    void UpdatePosition(CDC* pDC, const CRect& rcControl);    TChartString m_strFontName;    int          m_iFontSize;    bool m_bDocked;    // true if the legend is docked    DockSide m_DockSide;    // If the legend is not docked:    int m_iLeftPos;    int m_iTopPos;    bool m_bIsTransparent;    bool m_bIsHorizontal;    CSize m_BitmapSize;};#endif // !defined(AFX_CHARTLEGEND_H__CD72E5A0_8F52_472A_A611_C588F642080B__INCLUDED_)

CChartLegend类的源文件。

#include "stdafx.h"#include "ChartLegend.h"#include "ChartSerie.h"#include "ChartCtrl.h"#ifdef _DEBUG#undef THIS_FILEstatic char THIS_FILE[]=__FILE__;#define new DEBUG_NEW#endif//// Construction/Destruction//CChartLegend::CChartLegend(CChartCtrl* pParent):CChartObject(pParent){    m_ObjectColor = RGB(255,255,255);    m_iFontSize = 100;    m_strFontName = _T("Times New Roman");    m_bIsVisible = false;    m_bDocked = true;    m_DockSide = dsDockRight;    m_iLeftPos = m_iTopPos = 0;    m_bIsTransparent = false;    m_bIsHorizontal = false;    m_bShadow = true;    m_iShadowDepth = 3;    m_BitmapSize.cx = 16;    m_BitmapSize.cy = 16;}CChartLegend::~CChartLegend(){}void CChartLegend::SetFont(int iPointSize, const TChartString& strFaceName){    m_iFontSize = iPointSize;    m_strFontName = strFaceName;    m_pParent->RefreshCtrl();}void CChartLegend::SetTransparent(bool bTransparent){    m_bIsTransparent = bTransparent;    m_pParent->RefreshCtrl();}void CChartLegend::SetHorizontalMode(bool bHorizontal){    m_bIsHorizontal = bHorizontal;    m_pParent->RefreshCtrl();}void CChartLegend::DockLegend(DockSide dsSide){    m_bDocked = true;    m_DockSide = dsSide;    m_pParent->RefreshCtrl();}void CChartLegend::UndockLegend(int iLeftPos, int iTopPos){    m_bDocked = false;    m_iLeftPos = iLeftPos;    m_iTopPos = iTopPos;    m_pParent->RefreshCtrl();}void CChartLegend::ClipArea(CRect& rcControl, CDC* pDC){    UpdatePosition(pDC,rcControl);    if (m_ObjectRect.IsRectEmpty())        return;    if (m_bDocked)    {        switch (m_DockSide)        {        case dsDockRight:            rcControl.right = m_ObjectRect.left + 2;            break;        case dsDockLeft:            rcControl.left = m_ObjectRect.right - 2;            break;        case dsDockTop:            rcControl.top = m_ObjectRect.bottom + 2;            break;        case dsDockBottom:            rcControl.bottom = m_ObjectRect.top - 2;            break;        }    }}void CChartLegend::UpdatePosition(CDC* pDC, const CRect& rcControl){    CRect NewPosition;    NewPosition.SetRectEmpty();    if (!m_bIsVisible)    {        SetRect(NewPosition);        return;    }    CFont* pOldFont;    CFont NewFont;    NewFont.CreatePointFont(m_iFontSize,m_strFontName.c_str(),pDC);    pOldFont = pDC->SelectObject(&NewFont);    int Height = 0;            int Width = 0;            int MaxText = 0;    CSize TextSize;    size_t SeriesCount = m_pParent->GetSeriesCount();    int Drawn = 0;    for (size_t i=0;i
     
      GetSerie(i);        if ( (pSerie->GetName() == _T("")) || !pSerie->IsVisible() )            continue;        Drawn++;        TextSize = pDC->GetTextExtent(pSerie->GetName().c_str());        if (!m_bIsHorizontal)        {            if (TextSize.cy>m_BitmapSize.cy)                Height += TextSize.cy + 2;            else                Height += m_BitmapSize.cy + 2;            if (TextSize.cx > MaxText)                MaxText = TextSize.cx;        }        else        {            Width += TextSize.cx + 4 + m_BitmapSize.cx + 10;            if (TextSize.cy > MaxText)                MaxText = TextSize.cy;        }    }    pDC->SelectObject(pOldFont);    DeleteObject(NewFont);    if (!Drawn)    {        SetRect(NewPosition);        return;    }    if (!m_bIsHorizontal)    {        Width += MaxText + m_BitmapSize.cx + 12;        Height += 4 + 4 - 2;    // Top and bottom margins. -2 because space counted once too much    }    else    {        Width += 2 + 2 - 10;        Height = 4 + max(m_BitmapSize.cy,MaxText) + 4;    }        if (!m_bDocked)    {        NewPosition.top = m_iTopPos;        NewPosition.left = m_iLeftPos;        NewPosition.bottom = m_iTopPos + Height + 2;        NewPosition.right = m_iLeftPos + Width;    }    else    {        switch (m_DockSide)        {        case dsDockRight:            NewPosition.top = ((rcControl.bottom-rcControl.top)/2) - ((Height + 2)/2);            NewPosition.left = rcControl.right - (Width + 6);            NewPosition.bottom = NewPosition.top + Height;            NewPosition.right = NewPosition.left + Width;            break;        case dsDockLeft:            NewPosition.top = ((rcControl.bottom-rcControl.top)/2) - ((Height + 2)/2);            NewPosition.left = rcControl.left + 3;            NewPosition.bottom = NewPosition.top + Height;            NewPosition.right = NewPosition.left + Width;            break;        case dsDockTop:            NewPosition.top = rcControl.top + 3;  //((rcControl.bottom-rcControl.top)/2) - ((Height + 2)/2);            NewPosition.left = ((rcControl.right-rcControl.left)/2) - (Width/2);  // rcControl.left + 3;            NewPosition.bottom = NewPosition.top + Height;            NewPosition.right = NewPosition.left + Width;            break;        case dsDockBottom:            NewPosition.top = rcControl.bottom - (Height + 2);  //((rcControl.bottom-rcControl.top)/2) - ((Height + 2)/2);            NewPosition.left = ((rcControl.right-rcControl.left)/2) - (Width/2);  // rcControl.left + 3;            NewPosition.bottom = NewPosition.top + Height;            NewPosition.right = NewPosition.left + Width;            break;        }    }    SetRect(NewPosition);}void CChartLegend::Draw(CDC *pDC){    if (!pDC->GetSafeHdc())        return;    if (!m_bIsVisible)        return;    if (m_ObjectRect.IsRectEmpty())        return;    CPen SolidPen(PS_SOLID,0,RGB(0,0,0));    CPen* pOldPen;    CFont* pOldFont;    CFont NewFont;    NewFont.CreatePointFont(m_iFontSize,m_strFontName.c_str(),pDC);    // Draw the shadow    if (m_bShadow)    {        CRect ShadowRect = m_ObjectRect;        ShadowRect.OffsetRect(m_iShadowDepth,m_iShadowDepth);        CBrush BrushShadow;        BrushShadow.CreateSolidBrush(m_ShadowColor) ;        pDC->FillRect(ShadowRect,&BrushShadow);    }    if (!m_bIsTransparent)    {        //Fill back color        CBrush BrushBack;        BrushBack.CreateSolidBrush(m_ObjectColor) ;        pDC->FillRect(m_ObjectRect,&BrushBack);    }    pOldFont = pDC->SelectObject(&NewFont);    pOldPen = pDC->SelectObject(&SolidPen);    //Draw rectangle:    pDC->MoveTo(m_ObjectRect.left,m_ObjectRect.top);    pDC->LineTo(m_ObjectRect.right,m_ObjectRect.top);    pDC->LineTo(m_ObjectRect.right,m_ObjectRect.bottom);    pDC->LineTo(m_ObjectRect.left,m_ObjectRect.bottom);    pDC->LineTo(m_ObjectRect.left,m_ObjectRect.top);    int iPrevMode = pDC->SetBkMode(TRANSPARENT);    CRect rectBitmap(m_ObjectRect.left+2,m_ObjectRect.top+5,                     m_ObjectRect.left+2+m_BitmapSize.cx,                     m_ObjectRect.top+6+m_BitmapSize.cy);    int SeriesCount = m_pParent->GetSeriesCount();    for (int i=0;i
      
       GetSerie(i);        if ( (pSerie->GetName() == _T("")) || !pSerie->IsVisible() )            continue;        int MaxHeight = 0;        CSize TextSize = pDC->GetTextExtent(pSerie->GetName().c_str());        if (TextSize.cy > m_BitmapSize.cy)        {            pDC->ExtTextOut(rectBitmap.right+4,rectBitmap.top,ETO_CLIPPED,NULL,pSerie->GetName().c_str(),NULL);            CRect rectTemp(rectBitmap);            int YOffset = TextSize.cy/2 - rectBitmap.Height()/2;            rectTemp.OffsetRect(0,YOffset);            pSerie->DrawLegend(pDC,rectTemp);            MaxHeight = TextSize.cy;        }        else        {            int YOffset = rectBitmap.CenterPoint().y - TextSize.cy/2;            pDC->ExtTextOut(rectBitmap.right+4,YOffset,ETO_CLIPPED,NULL,pSerie->GetName().c_str(),NULL);            MaxHeight = m_BitmapSize.cy;            pSerie->DrawLegend(pDC,rectBitmap);        }                if (!m_bIsHorizontal)            rectBitmap.OffsetRect(0,MaxHeight+2);        else            rectBitmap.OffsetRect(m_BitmapSize.cx+4+TextSize.cx+10,0);    }    pDC->SetBkMode(iPrevMode);    pDC->SelectObject(pOldFont);    DeleteObject(NewFont);    pDC->SelectObject(pOldPen);    DeleteObject(SolidPen);}
      
     

ClipArea函数的作用是将ChartLegend与波形绘制区域分离开，其中rcControl表示的是绘制波形的区域，m_ObjectRect表示的是绘制ChartLegend的区域。UpdatePosition函数用来在当前绘制区域里面计算ChartLegend所处的位置并记录下该位置。Draw函数用来绘制ChartLegend控件，调用CChartSeries类的DrawLegend用来绘制ChartLegend里面的波形图像信息。