MFC GDI开发 异型窗口 和 抠图

//MemroyCD.h
class CMemoryDC :public CDC
{
  CSize m_size;
public:
  int GetWidth() const
  {
    return m_size.cx;
  }
  int GetHeight()const
  {
    return m_size.cy;
  }
  CSize GetSize()const
  {
    return m_size;
  }
  //根据透明图生成区域
  void MakeRgn(CRgn& r)
  {
    r.CreateRectRgn(0, 0, 0, 0);//产生句柄
    int j = 80;
    while (j--)
    {
      int i = 70;
      while (i--)
      {
        COLORREF c = GetPixel(i, j);
        if (c != 0xFF00FF)
        {
          CRgn r1;
          r1.CreateRectRgn(i, j, i + 1, j + 1);
          r.CombineRgn(&r, &r1, RGN_OR);
        }
      }
    }

  }
  void BitTrans(
    int nXDest,   // 目标起点X
    int nYDest,   // 目标起点Y
    int nWidthDest, // 目标宽度
    int nHeightDest,// 目标高度
    CDC* pDC,   // 目标DC
    int nXSrc,    // 来源起点X
    int nYSrc,    // 来源起点Y
    COLORREF crTrans// 透明色
  )
  {
    CMemoryDC dcImage(nWidthDest, nHeightDest, pDC);//临时DC
    CBitmap bmpMask;
    bmpMask.CreateBitmap(nWidthDest, nHeightDest, 1, 1, NULL);            // 创建单色掩码位图
    CDC dcMask;//掩码DC 
    dcMask.CreateCompatibleDC(pDC);
    dcMask.SelectObject(bmpMask);
    //将载入位图的内存DC中的位图，拷贝到临时DC中
    dcImage.BitBlt(0, 0, nWidthDest, nHeightDest, this, nXSrc, nYSrc, SRCCOPY);

    // 设置临时DC的透明色
    dcImage.SetBkColor(crTrans);
    //掩码DC的透明区域为白色其它区域为黑色
    dcMask.BitBlt(0, 0, nWidthDest, nHeightDest, &dcImage, 0, 0, SRCCOPY);

    //临时DC透明区域为黑色，其它区域保持不变
    dcImage.SetBkColor(RGB(0, 0, 0));
    dcImage.SetTextColor(RGB(255, 255, 255));
    dcImage.BitBlt(0, 0, nWidthDest, nHeightDest, &dcMask, 0, 0, SRCAND);

    // 目标DC透明部分保持屏幕不变，其它部分变成黑色
    pDC->SetBkColor(RGB(255, 255, 255));
    pDC->SetTextColor(RGB(0, 0, 0));
    pDC->BitBlt(nXDest, nYDest, nWidthDest, nHeightDest, &dcMask, 0, 0, SRCAND);
    pDC->BitBlt(nXDest, nYDest, nWidthDest, nHeightDest, &dcImage, 0, 0, SRCPAINT);
  }
  void StretchTrans(
    int nXDest,     // 目标起点X
    int nYDest,     // 目标起点Y
    int nWidthDest,     // 目标宽度
    int nHeightDest,    // 目标高度
    CDC* pDC,     // 目标DC
    int nXSrc,      // 来源起点X
    int nYSrc,      // 来源起点Y
    int nWidthSrc,    // 来源宽度
    int nHeightSrc,   // 来源高度
    COLORREF crTrans  // 透明色
  )
  {
    CMemoryDC dcImage(nWidthDest, nHeightDest, pDC);//临时DC
    CBitmap bmpMask;
    // 创建单色掩码位图
    bmpMask.CreateBitmap(nWidthDest, nHeightDest, 1, 1, NULL);
    CDC dcMask;
    dcMask.CreateCompatibleDC(pDC);
    dcMask.SelectObject(bmpMask);

    // 将载入位图的内存DC中的位图，拷贝到临时DC中
    if (nWidthDest == nWidthSrc && nHeightDest == nHeightSrc)
      dcImage.BitBlt(0, 0, nWidthDest, nHeightDest, this, nXSrc, nYSrc, SRCCOPY);
    else
      dcImage.StretchBlt(0, 0, nWidthDest, nHeightDest,
        this, nXSrc, nYSrc, nWidthSrc, nHeightSrc, SRCCOPY);

    // 设置临时DC的透明色
    dcImage.SetBkColor(crTrans);
    //掩码DC的透明区域为白色其它区域为黑色
    dcMask.BitBlt(0, 0, nWidthDest, nHeightDest, &dcImage, 0, 0, SRCCOPY);

    //临时DC透明区域为黑色，其它区域保持不变
    dcImage.SetBkColor(RGB(0, 0, 0));
    dcImage.SetTextColor(RGB(255, 255, 255));
    dcImage.BitBlt(0, 0, nWidthDest, nHeightDest, &dcMask, 0, 0, SRCAND);

    // 目标DC透明部分保持屏幕不变，其它部分变成黑色
    pDC->SetBkColor(RGB(255, 255, 255));
    pDC->SetTextColor(RGB(0, 0, 0));
    pDC->BitBlt(nXDest, nYDest, nWidthDest, nHeightDest, &dcMask, 0, 0, SRCAND);
    pDC->BitBlt(nXDest, nYDest, nWidthDest, nHeightDest, &dcImage, 0, 0, SRCPAINT);
  }
  //从资源中加载位图
  BOOL LoadBitmap(UINT nBitmapID, CDC* pDC = NULL)
  {
    CBitmap bitmap;
    bitmap.LoadBitmap(nBitmapID);
    BITMAP bm;
    bitmap.GetBitmap(&bm);
    m_size.cx = bm.bmWidth;
    m_size.cy = bm.bmHeight;
    CreateCompatibleDC(pDC);
    SelectObject(bitmap);
    return TRUE;
  }
  //创建一张空白内存画布
  BOOL Create(int cx, int cy, CDC* pDC = NULL)
  {
    CreateCompatibleDC(pDC);
    CBitmap bitmap;
    if (pDC)
      bitmap.CreateCompatibleBitmap(pDC, cx, cy);
    else
      bitmap.CreateCompatibleBitmap(&CClientDC(NULL), cx, cy);
    m_size.cx = cx;
    m_size.cy = cy;
    SelectObject(bitmap);
    return TRUE;
  }
  explicit CMemoryDC(int cx, int cy, CDC* pDC = NULL)
  {
    Create(cx, cy, pDC);
  }
  explicit CMemoryDC(UINT nBitmapID, CDC* pDC = NULL)
  {
    LoadBitmap(nBitmapID, pDC);
  }
  CMemoryDC() :m_size(0, 0)
  {

  }
};

//Dlg.h
#include "MemroyCD.h"
class CDlg : public CDialogEx
{
// 构造
  enum { FLY_COUNT = 7 };
  CRgn m_rs[FLY_COUNT];
  CMemoryDC m_dc[FLY_COUNT]{};
  int m_nIndex{ 0 };
  CPoint m_pos, m_dir{5,5};
  CSize m_size;
}

//Dlg.cpp
BOOL CDlg::OnInitDialog()
{
  CDialogEx::OnInitDialog();
  int i = _countof(m_dc);
  while (i--)
  {
    m_dc[i].LoadBitmap(IDB_BITMAP1 + i);
    m_dc[i].MakeRgn(m_rs[i]);
  }
  if (rand() % 2)
    m_dir.x *= -1;
  if(rand()%2)
    m_dir.y *= -1;
  m_size.cx = GetSystemMetrics(SM_CXSCREEN) - m_dc->GetWidth();
  m_size.cy = GetSystemMetrics(SM_CYSCREEN) - m_dc->GetHeight();
  m_pos.x = rand() % m_size.cx;
  m_pos.y = rand() % m_size.cy;

  MoveWindow(m_pos.x, m_pos.y, m_dc->GetWidth(), m_dc->GetHeight(), false);
  SetTimer(1, 32, 0);
  if (++m_nIndex > _countof(m_rs))
    m_nIndex = 0;
  return TRUE;  // 除非将焦点设置到控件，否则返回 TRUE
}

void CDlg::OnPaint()
{
  CPaintDC dc(this); // 用于绘制的设备上下文
  CRgn r;
  r.CreateRectRgn(0, 0, 0, 0);
  r.CopyRgn(&m_rs[m_nIndex]);
  SetWindowRgn(r, false);
  m_dc[m_nIndex].BitTrans(0, 0, m_dc->GetWidth(), m_dc->GetHeight(), &dc, 0, 0, 0xff00ff);
}


void CDlg::OnTimer(UINT_PTR nIDEvent)
{
  
  //CPaintDC dc(this); 
  CClientDC dc(this);
  CRgn r;
  r.CreateRectRgn(0, 0, 0, 0);
  r.CopyRgn(&m_rs[m_nIndex]);
  MoveWindow(CRect{ m_pos,m_dc->GetSize() }, FALSE);
  SetWindowRgn(r, false);
  dc.BitBlt(0, 0, m_dc->GetWidth(), m_dc->GetHeight(), &m_dc[m_nIndex], 0, 0, SRCCOPY);
  if (++m_nIndex >= _countof(m_rs))
    m_nIndex = 0;

  m_pos.Offset(m_dir);

  if (m_pos.y > m_size.cy || m_pos.y < 0)
    m_dir.y *= -1;
  if (m_pos.x > m_size.cx || m_pos.x < 0)
    m_dir.x *= -1;

  CDialogEx::OnTimer(nIDEvent);
}

粉色RGB值为0xFF00FF为要扣掉的区域