C / C++ / MFC

#include <windows.h>

#pragma comment(lib,"user32.lib")

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR pszCmdLine, int cmdShow)
{
    // create a virtual dc to draw elements.
    HDC		hdcScreen     = CreateDC("DISPLAY", NULL, NULL, NULL); 
    HDC		hdcCompatible = CreateCompatibleDC(hdcScreen);
    CString     m_strText = _T("Hello");
    SIZE        m_sz;
    
    if(hdcCompatible == NULL)
    {
        MessageBox(NULL,_T("CreateCompatibleDC Failed !"),NULL,NULL);
        return -1;
    }
    
    // then set the text color is black,the back color is white.
    SetBkColor(hdcCompatible,RGB(255,255,255));
    SetTextColor(hdcCompatible,RGB(0,0,0));
    
    // draw the text int a virtual dc.
    TextOut(hdcCompatible,0,0,m_strText,m_strText.GetLength());
	
    // get the text width and height.
    GetTextExtentPoint32(hdcCompatible,m_strText,m_strText.GetLength(),&m_sz);
    
    // get the pixel infomation.
    for(int i=0; i<m_sz.cx; i++)
    {
        for(int j=0; j<m_sz.cy; j++)
        {
            COLORREF color = GetPixel(hdcCompatible,i,j);
            if(color == RGB(255,255,255)
            {
                // do something.
            }
            else
            {
                // do something.
            }
        }
    }
}

  class Manager ;
  class IManager
{
public :
    virtual void __stdcall fun(Manager* ptr)=0 ;
};

#include "interface.h"
     class Manager
   {
   public :
       Manager () ;
       ~Manager () ;
       IManager* GetMyManager () ;
               IManager* _VarManager ;
       };