ChartCtrl源码剖析之——CChartTitle类

CChartTitle类顾名思义，该类用来绘制波形控件的标题，它处于该控件的区域，如下图所示：

CChartTitle类的头文件。

#if !defined(AFX_CHARTTITLE_H__49972787_6D28_4F81_A12F_420947456913__INCLUDED_)

#define AFX_CHARTTITLE_H__49972787_6D28_4F81_A12F_420947456913__INCLUDED_

#if _MSC_VER > 1000

#pragma once

#endif // _MSC_VER > 1000

#include "ChartObject.h"

#include <vector>

#include "ChartString.h"

class CChartTitle : public CChartObject

{

    friend CChartCtrl;

public:

    size_t GetStringCount() const;

    TChartString GetString(size_t Index) const;

    void AddString(const TChartString& NewString);

    void RemoveAll();

    void SetFont(int iPointSize, const TChartString& strFaceName);

    CChartTitle(CChartCtrl* pParent);

    virtual ~CChartTitle();

private:

    CSize GetSize(CDC* pDC);

    void Draw(CDC *pDC);

    std::vector<TChartString> m_StringArray;

    TChartString m_strFontName;

    int          m_iFontSize;

};

#endif // !defined(AFX_CHARTTITLE_H__49972787_6D28_4F81_A12F_420947456913__INCLUDED_)

其中，ChartString.h头文件。

#pragma once

#include <string>

#if defined _UNICODE || defined UNICODE

    typedef std::wstring TChartString;

#else

    typedef std::string TChartString;

#endif

CChartTitle类的源文件。

#include "stdafx.h"

#include "ChartTitle.h"

#include "ChartCtrl.h"

#include "Math.h"

using namespace std;

#ifdef _DEBUG

#undef THIS_FILE

static char THIS_FILE[]=__FILE__;

#define new DEBUG_NEW

#endif

//////////////////////////////////////////////////////////////////////

// Construction/Destruction

//////////////////////////////////////////////////////////////////////

CChartTitle::CChartTitle(CChartCtrl* pParent) : CChartObject(pParent)

{

    m_ObjectColor = RGB(,,);

    m_iFontSize = ;

    m_strFontName = _T("Microsoft Sans Serif");

}

CChartTitle::~CChartTitle()

{

}

void CChartTitle::SetFont(int iPointSize, const TChartString& strFaceName)

{

    m_iFontSize = iPointSize;

    m_strFontName = strFaceName;

    m_pParent->RefreshCtrl();

}

void CChartTitle::AddString(const TChartString& NewString)

{

    m_StringArray.push_back(NewString);

    m_pParent->RefreshCtrl();

}

size_t CChartTitle::GetStringCount() const

{

    return m_StringArray.size();

}

TChartString CChartTitle::GetString(size_t Index) const

{

    if ( (Index<) || (Index>=m_StringArray.size()) )

        return _T("");

    return m_StringArray[Index];

}

void CChartTitle::RemoveAll()

{

    m_StringArray.clear();

    m_pParent->RefreshCtrl();

}

void CChartTitle::Draw(CDC *pDC)

{

    if (!pDC->GetSafeHdc())

        return;

    if (!m_bIsVisible)

        return;

    CFont* pOldFont;

    CFont NewFont;

    NewFont.CreatePointFont(m_iFontSize,m_strFontName.c_str(),pDC);

    COLORREF OldColor = pDC->SetTextColor(m_ObjectColor);

    pOldFont = pDC->SelectObject(&NewFont);

    int iPrevMode = pDC->SetBkMode(TRANSPARENT);

    //Draw all entries

    int YPos = ;

    size_t TitleCount = m_StringArray.size();

    for (size_t i=;i<TitleCount;i++)

    {

        //Draw Text

        int TextWidth = pDC->GetTextExtent(m_StringArray[i].c_str()).cx;

        int TextHeigh = pDC->GetTextExtent(m_StringArray[i].c_str()).cy;

        int XPos = m_ObjectRect.left + (int)fabs((m_ObjectRect.left-m_ObjectRect.right)/2.0) - TextWidth/;

        if (m_bShadow)

        {

            pDC->SetTextColor(m_ShadowColor);

            pDC->ExtTextOut(XPos+m_iShadowDepth,m_ObjectRect.top+YPos+m_iShadowDepth,

                            ETO_CLIPPED,NULL,m_StringArray[i].c_str(),NULL);

            pDC->SetTextColor(m_ObjectColor);

        }

        pDC->ExtTextOut(XPos,m_ObjectRect.top+YPos,ETO_CLIPPED,NULL,m_StringArray[i].c_str(),NULL);

        YPos += TextHeigh + ;

    }

    pDC->SelectObject(pOldFont);

    DeleteObject(NewFont);

    pDC->SetTextColor(OldColor);

    pDC->SetBkMode(iPrevMode);

}

CSize CChartTitle::GetSize(CDC *pDC)

{

    CSize TitleSize;

    if (!m_bIsVisible)

    {

        TitleSize.cx = TitleSize.cy = ;

        return TitleSize;

    }

    int Height = ;        //Upper space

    CSize TextSize = ;

    int MaxTextWidth = ;

    size_t TitleCount = m_StringArray.size();

    if (TitleCount==)

    {

        TitleSize.cx = TitleSize.cy = ;

        return TitleSize;

    }

    CFont* pOldFont;

    CFont NewFont;

    NewFont.CreatePointFont(m_iFontSize,m_strFontName.c_str(),pDC);

    pOldFont = pDC->SelectObject(&NewFont);

    for (size_t i=;i<TitleCount;i++)

    {

        TextSize = pDC->GetTextExtent(m_StringArray[i].c_str());

        Height += TextSize.cy + ;

        if (TextSize.cx > MaxTextWidth)

            MaxTextWidth = TextSize.cx;

    }

    TitleSize.cx = MaxTextWidth + ;

    TitleSize.cy = Height;

    m_ObjectRect.bottom = m_ObjectRect.top + Height;

    pDC->SelectObject(pOldFont);

    DeleteObject(NewFont);

    return TitleSize;

}

GetSize函数用来获取标题文字的长度和宽度，Draw函数用来在指定位置绘制标题文字。在初次阅读这份源码的时候在如何确定m_ObjectRect大小的时候纠结了很长时间，现在读的时候感觉无比顺畅，真是应了那句古话，书读百遍其义自现，代码读个三五遍，一开始读不懂的统统全部拿下，感觉特别Happy。