MFC内存绘图设备封装类

#ifndef MEMDC_H
#define MEMDC_H

class CMemoryDC :public CDC
{
CSize m_size;
public:
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);}CMemoryDC(){    m_size.cx = m_size.cy = 0;}//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;}CMemoryDC(UINT nBitmapID, CDC* pDC = NULL){    LoadBitmap(nBitmapID, pDC);}//从.bmp文件中加载位图BOOL LoadBitmap(LPCTSTR szBitmapFile, CDC* pDC = NULL){    HBITMAP hBitmap = (HBITMAP)LoadImage(AfxGetInstanceHandle(),        szBitmapFile, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);    BITMAP bm;    GetObject(hBitmap, sizeof(bm), &bm);    m_size.cx = bm.bmWidth;    m_size.cy = bm.bmHeight;    CreateCompatibleDC(pDC);    SelectObject(hBitmap);    return TRUE;}CMemoryDC(LPCTSTR szBitmapFile, CDC* pDC = NULL){    LoadBitmap(szBitmapFile, pDC);}//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;}CMemoryDC(int cx, int cy, CDC* pDC = NULL){    Create(cx, cy, pDC);}//摧毁BOOL DeleteDC(){    if (!GetSafeHdc())        return TRUE;    CBitmap * pBitmap = GetCurrentBitmap();    pBitmap->DeleteObject();    return CDC::DeleteDC();}~CMemoryDC(){    DeleteDC();}inline int Width() { return m_size.cx; }inline int Height() { return m_size.cy; }void CMemoryDC::BitRgn(CRgn &rgn,/*目标区域*/COLORREF crTrans/*透明色*/){    //根据当前位图和透明色生成一个不规则区域    int i = 0, j = 0;    rgn.CreateRectRgn(0, 0, 0, 0);    while (i < m_size.cx)    {        j = 0;        while (j < m_size.cy)        {            if (GetPixel(i, j) - crTrans)            {                //如果不是透明色就在区域内增加一个点                CRgn r;                r.CreateRectRgn(i, j, i + 1, j + 1);                rgn.CombineRgn(&rgn, &r, RGN_OR);            }            ++j;        }        ++i;    }}

};

#endif //MEMDC_H