cgdi.shtml

来自「mfc资源大全包含MFC编程各个方面的源码」· SHTML 代码 · 共 284 行

SHTML
284 行
字号 
<HTML>

<!-- Header information-->
<HEAD>
   <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
   <META NAME="Author" CONTENT="Michael S. Scherotter">
   <TITLE>CGDI - Simple GDI Set And Reset</TITLE>
</HEAD>

<!-- Set background properties -->
<body background="/fancyhome/back.gif" bgcolor="#FFFFFF">

<!-- A word from our sponsors... -->
<table WIDTH="100%">
<tr WIDTH="100%"><td align=center><!--#exec cgi="/cgi/ads.cgi"--><td></tr>
</table>


<CENTER><H3><FONT COLOR="#AOAO99">
<!-- Article Title -->
CGDI - Simple GDI Set And Reset
</FONT></H3></CENTER>
<HR>

<!-- Author and contact details -->
This article was contributed by <A HREF="mailto:mss@tartus.com">Michael S. Scherotter</A>.

<!-- The article... -->

<p>In MFC, GDI Objects need to be selected and then destroyed. CGDI and its derived classes
take care of this by selecting the object in the constructor and deselecting it in the destructor.
CGDIObject is a template class which takes as its parameter the CGdiObject-derived class.  This
class library only accounts for a few of the set/get function pairs.  This could be extended by 
creating classes for each of the CDC Set/Get functions.

Examples:
<FONT COLOR="#990000"><TT><PRE>

// Example to draw a line using the BLACK_PEN stock object
void DrawLine(CDC* pDC)
{
    CStockObject theObject(pDC, BLACK_PEN);

    pDC->LineTo(100, 100);
}

// Example to draw a line using a custom pen
void DrawLinesWithPen(CDC* pDC)
{                                                         // Current Pen Selected
    CPen thePen(PS_SOLID, 3, RGB(100, 200, 2));

    CGDIObject&ltCPen&gt theObject(pDC, &thePen);                  // thePen Selected

    pDC->LineTo(100, 100);

    // Use brackets to nest calls
    {
        CPen theOtherPen(PS_SOLID, 3, RGB(200, 10, 2));         

        CGDIObject&ltCPen&gt theOtherObject(pDC, &theOtherPen);    // theOtherPen Selected

        pDC->LineTo(200, 200);
    }                                                     // thePen Selected

    pDC->LineTo(300, 300);
}                                                         // Current Pen Selected




// helper template function for unused parameters
template &ltclass T&gt
void Unused(T rT)
{
    static_cast&ltvoid&gt(rT);
};


class CGDI
{
protected:
    CDC* m_pDC;

    CGDI(CDC* pDC) : 
      m_pDC(pDC)
    {
    }

    virtual ~CGDI()
    {
        m_pDC = NULL;
    }
};

// Class to select a stock object
class CGDIStockObject : public CGDI
{
    CGdiObject* m_pLastObject;

public:
    CGDIStockObject(CDC* pDC, int nIndex) : CGDI(pDC),
      m_pLastObject(NULL)
    {
        m_pLastObject = m_pDC->SelectStockObject(nIndex);
    }

    virtual ~CGDIStockObject()
    {
        if (m_pLastObject)
        {
            Unused(m_pDC->SelectObject(m_pLastObject));

            m_pLastObject = NULL;
        }
    }
};


class CGDITextColor : public CGDI
{
    COLORREF m_LastColor;

public:
    CGDITextColor(CDC* pDC, COLORREF theColor) : CGDI(pDC),
      m_LastColor(RGB(0,0,0))
    {
        m_LastColor = m_pDC->SetTextColor(theColor);
    }

    virtual ~CGDITextColor()
    {
        Unused(m_pDC->SetTextColor(m_LastColor));
    }

};

class CGDIBackColor : public CGDI
{
    COLORREF m_LastColor;

public:
    CGDIBackColor(CDC* pDC, COLORREF theColor) : CGDI(pDC),
      m_LastColor(RGB(0,0,0))
    {
        m_LastColor = m_pDC->SetBkColor(theColor);
    }

    virtual ~CGDIBackColor()
    {
        Unused(m_pDC->SetBkColor(m_LastColor));
    }

};

class CGDIBackMode : public CGDI
{
    int m_LastMode;

public:
    CGDIBackMode(CDC* pDC, int theMode) : CGDI(pDC),
	  m_LastMode(0)
    {
        m_LastMode = m_pDC->SetBkMode(theMode);
    }

    virtual ~CGDIBackMode()
    {
        Unused(m_pDC->SetBkMode(m_LastMode));
    }

};

// This class can be used like this:
// CGDIObject&ltCFont&gt(pDC, pFont);
// CGDIObject&ltCPen&gt(pDC, pPen);

template &ltclass T&gt
class CGDIObject : public CGDI
{
T* m_pLast;

public:
    CGDIObject(CDC* pDC, T* pObject) : CGDI(pDC), 
	  m_pLast(NULL)
    {
        if (pObject)
        {
            m_pLast = pDC->SelectObject(pObject);
        }
    }

    virtual ~CGDIObject()
    {
        if (m_pLast)
        {
            Unused(m_pDC->SelectObject(m_pLast));

            m_pLast = NULL;
        }
    }
};

class CGDITextAlign : public CGDI
{
UINT m_Last;

public:
    CGDITextAlign(CDC* pDC, UINT nTextAlign) : CGDI(pDC),
	  m_Last(0)
    {
        m_Last = pDC->SetTextAlign(nTextAlign);
    }

    virtual ~CGDITextAlign()
    {
        Unused(m_pDC->SetTextAlign(m_Last));
    }
};


class CGDIROP : public CGDI
{
int m_Last;

public:
    CGDIROP(CDC* pDC, int nROP) : CGDI(pDC),
	  m_Last(0)
    {
        m_Last = pDC->SetROP2(nROP);
    }

    virtual ~CGDIROP()
    {
        Unused(m_pDC->SetROP2(m_Last));
    }
};

class CGDIMapMode : public CGDI
{
int m_Last;

public:
    CGDIMapMode(CDC* pDC, int nMapMode) : CGDI(pDC),
	  m_Last(0)
    {
        m_Last = pDC->SetMapMode(nMapMode);
    }

    virtual ~CGDIMapMode()
    {
        Unused(m_pDC->SetMapMode(m_Last));
    }
};

</tt></PRE></FONT>

<!-- Remember to update this -->
<p>Last updated: 8 June 1998

<P><HR>

<!-- Codeguru contact details -->
<TABLE BORDER=0 WIDTH="100%">
<TR>
<TD WIDTH="33%"><FONT SIZE=-1><A HREF="http://www.codeguru.com">Goto HomePage</A></FONT></TD>

<TD WIDTH="33%">
<CENTER><FONT SIZE=-2>&copy; 1998 Zafir Anjum</FONT>&nbsp;</CENTER>
</TD>

<TD WIDTH="34%">
<DIV ALIGN=right><FONT SIZE=-1>Contact me: <A HREF="mailto:zafir@home.com">zafir@home.com</A>&nbsp;</FONT></DIV>
</TD>
</TR>
</TABLE>

<!-- Counter -->
<CENTER><FONT SIZE=-2><!--#exec cgi="../cgi/counters/counter.cgi"--></FONT></CENTER>


</BODY>
</HTML>

cgdi.shtml - 源码说明

本页面展示了「mfc资源大全包含MFC编程各个方面的源码」中的 cgdi.shtml 源码文件，采用 SHTML 编程语言编写，共 284 行代码。您可以在线阅读完整代码内容，也可以返回资源详情页下载完整源码包进行本地学习和开发。

虫虫下载站收录了大量与mfc相关的技术资源，包括源代码、技术文档、电路图等，是电子工程师和嵌入式开发者的专业学习平台。

⌨️ 快捷键说明

复制代码Ctrl + C
搜索代码Ctrl + F
全屏模式F11
增大字号Ctrl + =
减小字号Ctrl + -
显示快捷键?