ChartCtrl源码剖析之——CChartAxisLabel类

CChartAxisLabel类用来绘制轴标签，上、下、左、右都可以根据实际需要设置对应的轴标签。它处于该控件的区域，如下图所示：

CChartAxisLabel类的头文件。

#if !defined(AFX_CHARTAXISLABEL_H__0E5519C8_A2F4_4CED_9681_32A56B25D0C5__INCLUDED_)
#define AFX_CHARTAXISLABEL_H__0E5519C8_A2F4_4CED_9681_32A56B25D0C5__INCLUDED_
#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000
#include "ChartObject.h"
#include "ChartString.h"
class CChartAxis;
class CChartAxisLabel : public CChartObject  
{
    friend CChartAxis;
public:
    void SetText(const TChartString& NewText);
    TChartString GetText() const        { return m_strLabelText;    }
    void SetFont(int nPointSize, const TChartString& strFaceName);
    CChartAxisLabel(CChartCtrl* pParent, bool bHorizontal);
    virtual ~CChartAxisLabel();
private:
    void SetPosition(int LeftBorder, int TopBorder, CDC *pDC);
    void Draw(CDC* pDC);
    CSize GetSize(CDC* pDC) const;
    bool m_bIsHorizontal;      // Specifies if the axis is horizontal or not
    int  m_iFontSize;
    TChartString m_strFontName;
    TChartString m_strLabelText;
};
#endif // !defined(AFX_CHARTAXISLABEL_H__0E5519C8_A2F4_4CED_9681_32A56B25D0C5__INCLUDED_)

CChartAxisLabel类的源文件。

#include "stdafx.h"
#include "ChartAxisLabel.h"
#include "ChartCtrl.h"
#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif
//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////
CChartAxisLabel::CChartAxisLabel(CChartCtrl* pParent, bool bHorizontal):CChartObject(pParent)
{
    m_bIsHorizontal = bHorizontal;
    m_iFontSize = 100;
    m_strFontName = _T("Microsoft Sans Serif");
    m_strLabelText = _T("");
}
CChartAxisLabel::~CChartAxisLabel()
{
}
void CChartAxisLabel::SetText(const TChartString& NewText)  
{
    m_strLabelText = NewText;
    m_pParent->RefreshCtrl();
}
void CChartAxisLabel::SetFont(int nPointSize, const TChartString& strFaceName)
{
    m_iFontSize = nPointSize;
    m_strFontName = strFaceName;
    m_pParent->RefreshCtrl();
}
CSize CChartAxisLabel::GetSize(CDC *pDC) const
{
    CSize LabelSize;
    LabelSize.cx = 0;
    LabelSize.cy = 0;
    if (!m_bIsVisible)
        return LabelSize;
    if (!pDC->GetSafeHdc())
        return LabelSize;
    if (m_strLabelText == _T(""))
        return LabelSize;
    CFont NewFont;
    CFont* pOldFont;
    NewFont.CreatePointFont(m_iFontSize,m_strFontName.c_str(),pDC);
    pOldFont = pDC->SelectObject(&NewFont);
    LabelSize = pDC->GetTextExtent(m_strLabelText.c_str());
    LabelSize.cx += 4;
    LabelSize.cy += 4;
    if (!m_bIsHorizontal)
    {
        int Width = LabelSize.cy;
        int Height = LabelSize.cx;
        LabelSize.cx = Width;
        LabelSize.cy = Height;
    }
    pDC->SelectObject(pOldFont);
    DeleteObject(NewFont);
    return LabelSize;
}
void CChartAxisLabel::Draw(CDC *pDC)
{
    if (!m_bIsVisible)
        return;
    if (!pDC->GetSafeHdc())
        return;
    if (m_strLabelText == _T(""))
        return;
    int iPrevMode = pDC->SetBkMode(TRANSPARENT);
    COLORREF OldColor = pDC->SetTextColor(m_ObjectColor);
    CFont NewFont;
    NewFont.CreatePointFont(m_iFontSize,m_strFontName.c_str(),pDC);
    CFont* pOldFont;
    if (!m_bIsHorizontal)
    {
        LOGFONT LogFont;
        NewFont.GetLogFont(&LogFont);
        LogFont.lfOrientation = 900;
        LogFont.lfEscapement = 900;
        CFont VertFont;
        VertFont.CreateFontIndirect(&LogFont);
        pOldFont = pDC->SelectObject(&VertFont);
        pDC->ExtTextOut(m_ObjectRect.left + 2,m_ObjectRect.top,
                    ETO_CLIPPED,NULL,m_strLabelText.c_str(),NULL);
        pDC->SelectObject(pOldFont);
        DeleteObject(VertFont);
        DeleteObject(NewFont);
    }
    else
    {        
        pOldFont = pDC->SelectObject(&NewFont);
        pDC->ExtTextOut(m_ObjectRect.left,m_ObjectRect.top + 2,
                    ETO_CLIPPED,NULL,m_strLabelText.c_str(),NULL);
        pDC->SelectObject(pOldFont);
        DeleteObject(NewFont);
    }
    pDC->SetBkMode(iPrevMode);
    pDC->SetTextColor(OldColor);
}
void CChartAxisLabel::SetPosition(int LeftBorder, int TopBorder, CDC *pDC)
{
    CSize NewSize = GetSize(pDC);
    CRect NewRect;
    NewRect.top = TopBorder;
    NewRect.bottom = TopBorder + NewSize.cy;
    NewRect.left = LeftBorder;
    NewRect.right = LeftBorder + NewSize.cx;
    CChartObject::SetRect(NewRect);
}

CChartAxisLabel类在CChartAxis类中设定最终绘制的位置。