C++ 透明位图

在开发界面及棋牌游戏过程中，需要很多镂空的图片,而且图片形式一般比较固定.
所以封装了几种常见的镂空方法.

1. 用于没有掩码图,只有指定透明色,不进行伸缩
void DrawTransBitmap( HDC hdcDest,             // 目标DC
                      int nXOriginDest,        // 目标X偏移
                      int nYOriginDest,        // 目标Y偏移
                      int nWidthDest,          // 目标宽度
                      int nHeightDest,         // 目标高度
                      HDC hdcSrc,              // 源DC
                      int nXOriginSrc,         // 源X起点
                      int nYOriginSrc,         // 源Y起点
                      COLORREF crTransparent   // 透明色,COLORREF类型
                    );

2. 用于没有掩码图,只有指定透明色,可以进行伸缩
 void DrawTransBitmap( HDC hdcDest,       // 目标DC
                                             int nXOriginDest,   // 目标X偏移
                                             int nYOriginDest,   // 目标Y偏移
                                             int nWidthDest,      // 目标宽度
                                             int nHeightDest,    // 目标高度
                                             HDC hdcSrc,          // 源DC
                                             int nXOriginSrc,     // 源X起点
                                             int nYOriginSrc,     // 源Y起点
                                             int nWidthSrc,        // 源宽度
                                             int nHeightSrc,      // 源高度
                                             COLORREF crTransparent  // 透明色,COLORREF类型
      );

3.指定掩码图,和掩码图属于不同图片
 void DrawTransBitmap( HDC hdcDest,        // 目标DC
                                             int nXOriginDest,    // 目标X偏移
                                             int nYOriginDest,    // 目标Y偏移
                                             int nWidthDest,       // 目标宽度
                                             int nHeightDest,     // 目标高度
                                             HDC hdcSrc,          // 源DC
                                             HDC hdcMask,       //掩码DC
                                             int nXOriginSrc,     // 源X起点
                                             int nYOriginSrc,     // 源Y起点
                                            COLORREF crTransparent  // 透明色,COLORREF类型
                                          );

4.指定图片和掩码图同属于一张图片
void DrawTransBitmap(HDC hDC, 
                                           int nPosX, 
                                           int nPosY,
                                           int nCX, 
                                           int nCY, 
                                           HBITMAP hObj
                                           );

5.得到位图HRGN
   HRGN CreateBitmapRgn(int nWidth,int nHeight,HBITMAP hbmp,COLORREF cTrans);

以下是完整代码
//用于没有掩码图,只有指定透明色,不进行伸缩
//方法一：
void DrawTransBitmap( HDC hdcDest,      // 目标DC
                    int nXOriginDest,   // 目标X偏移
                    int nYOriginDest,   // 目标Y偏移
                    int nWidthDest,     // 目标宽度
                    int nHeightDest,    // 目标高度
                    HDC hdcSrc,         // 源DC
                    int nXOriginSrc,    // 源X起点
                    int nYOriginSrc,    // 源Y起点
                    COLORREF crTransparent  // 透明色,COLORREF类型
                    )
{
    HBITMAP hOldImageBMP, hImageBMP = CreateCompatibleBitmap(hdcDest, nWidthDest, nHeightDest);    // 创建兼容位图
    HBITMAP hOldMaskBMP, hMaskBMP = CreateBitmap(nWidthDest, nHeightDest, 1, 1, NULL);            // 创建单色掩码位图
    HDC        hImageDC = CreateCompatibleDC(hdcDest);//临时DC 
    HDC        hMaskDC = CreateCompatibleDC(hdcDest);//临时掩码DC 
    hOldImageBMP = (HBITMAP)SelectObject(hImageDC, hImageBMP);
    hOldMaskBMP = (HBITMAP)SelectObject(hMaskDC, hMaskBMP);

    // 将源DC中的位图拷贝到临时DC中,源DC已经载入位图
     BitBlt(hImageDC, 0, 0, nWidthDest, nHeightDest, hdcSrc, nXOriginSrc, nYOriginSrc, SRCCOPY);
 
    // 设置临时DC的透明色
    SetBkColor(hImageDC, crTransparent);

    // 生成透明区域为白色，其它区域为黑色的临时掩码DC的掩码位图
    // 位图来自临时DC
    BitBlt(hMaskDC, 0, 0, nWidthDest, nHeightDest, hImageDC, 0, 0, SRCCOPY);

    // 生成透明区域为黑色，其它区域保持不变的位图
    SetBkColor(hImageDC, RGB(0,0,0));
    SetTextColor(hImageDC, RGB(255,255,255));
    BitBlt(hImageDC, 0, 0, nWidthDest, nHeightDest, hMaskDC, 0, 0, SRCAND);

    // 透明部分保持屏幕不变，其它部分变成黑色
    SetBkColor(hdcDest,RGB(255,255,255));
    SetTextColor(hdcDest,RGB(0,0,0));
     BitBlt(hdcDest, nXOriginDest, nYOriginDest, nWidthDest, nHeightDest, hMaskDC, 0, 0, SRCAND);

    // "或"运算,生成最终效果
    BitBlt(hdcDest, nXOriginDest, nYOriginDest, nWidthDest, nHeightDest, hImageDC, 0, 0, SRCPAINT);

    // 清理、恢复    
    SelectObject(hImageDC, hOldImageBMP);
    DeleteDC(hImageDC);
    SelectObject(hMaskDC, hOldMaskBMP);
    DeleteDC(hMaskDC);
    DeleteObject(hImageBMP);
    DeleteObject(hMaskBMP);
}

//用于没有掩码图,只有指定透明色,不进行伸缩
//方法二：
void DrawTransBitmap( HDC hdcDest,      // 目标DC
                    int nXOriginDest,   // 目标X偏移
                    int nYOriginDest,   // 目标Y偏移
                    int nWidthDest,     // 目标宽度
                    int nHeightDest,    // 目标高度
                    HDC hdcSrc,         // 源DC
                    int nXOriginSrc,    // 源X起点
                    int nYOriginSrc,    // 源Y起点
                    COLORREF crTransparent  // 透明色,COLORREF类型
                    )
{
    HBITMAP hOldImageBMP, hImageBMP = CreateCompatibleBitmap(hdcDest, nWidthDest, nHeightDest);    // 创建兼容位图
    HBITMAP hOldMaskBMP, hMaskBMP = CreateBitmap(nWidthDest, nHeightDest, 1, 1, NULL);            // 创建单色掩码位图
    HDC        hImageDC = CreateCompatibleDC(hdcDest);//临时DC 
    HDC        hMaskDC = CreateCompatibleDC(hdcDest);//临时掩码DC 
    hOldImageBMP = (HBITMAP)SelectObject(hImageDC, hImageBMP);
    hOldMaskBMP = (HBITMAP)SelectObject(hMaskDC, hMaskBMP);

    // 将源DC中的位图拷贝到临时DC中,源DC已经载入位图
     BitBlt(hImageDC, 0, 0, nWidthDest, nHeightDest, hdcSrc, nXOriginSrc, nYOriginSrc, SRCCOPY);
 
    // 设置临时DC的透明色
    SetBkColor(hImageDC, crTransparent);

    // 生成透明区域为白色，其它区域为黑色的临时掩码DC的掩码位图
    // 位图来自临时DC
    BitBlt(hMaskDC, 0, 0, nWidthDest, nHeightDest, hImageDC, 0, 0, SRCCOPY);

            
    BitBlt(hdcDest, nXOriginDest, nYOriginDest, nWidthDest, nHeightDest, hImageDC, 0, 0, SRCINVERT);
         
    BitBlt(hdcDest, nXOriginDest, nYOriginDest, nWidthDest, nHeightDest, hMaskDC, 0, 0, SRCAND);

    BitBlt(hdcDest, nXOriginDest, nYOriginDest, nWidthDest, nHeightDest, hImageDC, 0, 0, SRCINVERT);
    // 清理、恢复    
    SelectObject(hImageDC, hOldImageBMP);
    DeleteDC(hImageDC);
    SelectObject(hMaskDC, hOldMaskBMP);
    DeleteDC(hMaskDC);
    DeleteObject(hImageBMP);
    DeleteObject(hMaskBMP);
}

//用于没有掩码图,只有指定透明色，可以进行伸缩
//方法一：
void DrawTransBitmap( HDC hdcDest,      // 目标DC
                     int nXOriginDest,   // 目标X偏移
                     int nYOriginDest,   // 目标Y偏移
                     int nWidthDest,     // 目标宽度
                     int nHeightDest,    // 目标高度
                     HDC hdcSrc,         // 源DC
                     int nXOriginSrc,    // 源X起点
                     int nYOriginSrc,    // 源Y起点
                     int nWidthSrc,      // 源宽度
                     int nHeightSrc,     // 源高度
                     COLORREF crTransparent  // 透明色,COLORREF类型
                     )
{
    HBITMAP hOldImageBMP, hImageBMP = CreateCompatibleBitmap(hdcDest, nWidthDest, nHeightDest);    // 创建兼容位图
    HBITMAP hOldMaskBMP, hMaskBMP = CreateBitmap(nWidthDest, nHeightDest, 1, 1, NULL);            // 创建单色掩码位图
    HDC        hImageDC = CreateCompatibleDC(hdcDest);
    HDC        hMaskDC = CreateCompatibleDC(hdcDest);
    hOldImageBMP = (HBITMAP)SelectObject(hImageDC, hImageBMP);
    hOldMaskBMP = (HBITMAP)SelectObject(hMaskDC, hMaskBMP);
    
    // 将源DC中的位图拷贝到临时DC中
    if (nWidthDest == nWidthSrc && nHeightDest == nHeightSrc)
    {
        BitBlt(hImageDC, 0, 0, nWidthDest, nHeightDest, hdcSrc, nXOriginSrc, nYOriginSrc, SRCCOPY);
    }
    else
    {
        StretchBlt(hImageDC, 0, 0, nWidthDest, nHeightDest, 
        hdcSrc, nXOriginSrc, nYOriginSrc, nWidthSrc, nHeightSrc, SRCCOPY);
    }
    
    // 设置透明色
    SetBkColor(hImageDC, crTransparent);

    // 生成透明区域为白色，其它区域为黑色的掩码位图
    BitBlt(hMaskDC, 0, 0, nWidthDest, nHeightDest, hImageDC, 0, 0, SRCCOPY);
    
    // 生成透明区域为黑色，其它区域保持不变的位图
    SetBkColor(hImageDC, RGB(0,0,0));
    SetTextColor(hImageDC, RGB(255,255,255));
    BitBlt(hImageDC, 0, 0, nWidthDest, nHeightDest, hMaskDC, 0, 0, SRCAND);

    // 透明部分保持屏幕不变，其它部分变成黑色
    SetBkColor(hdcDest,RGB(0xff,0xff,0xff));
    SetTextColor(hdcDest,RGB(0,0,0));
    BitBlt(hdcDest, nXOriginDest, nYOriginDest, nWidthDest, nHeightDest, hMaskDC, 0, 0, SRCAND);
    
    // "或"运算,生成最终效果
    BitBlt(hdcDest, nXOriginDest, nYOriginDest, nWidthDest, nHeightDest, hImageDC, 0, 0, SRCPAINT);
    
    SelectObject(hImageDC, hOldImageBMP);
    DeleteDC(hImageDC);
    SelectObject(hMaskDC, hOldMaskBMP);
    DeleteDC(hMaskDC);
    DeleteObject(hImageBMP);
    DeleteObject(hMaskBMP);
    
}

//用于没有掩码图,只有指定透明色，可以进行伸缩
  //方法二：
void DrawTransBitmap( HDC hdcDest,      // 目标DC
                     int nXOriginDest,   // 目标X偏移
                     int nYOriginDest,   // 目标Y偏移
                     int nWidthDest,     // 目标宽度
                     int nHeightDest,    // 目标高度
                     HDC hdcSrc,         // 源DC
                     int nXOriginSrc,    // 源X起点
                     int nYOriginSrc,    // 源Y起点
                     int nWidthSrc,      // 源宽度
                     int nHeightSrc,     // 源高度
                     COLORREF crTransparent  // 透明色,COLORREF类型
                     )
{
  
      if (nWidthDest < 1) return false;
      if (nWidthSrc < 1) return false;
      if (nHeightDest < 1) return false;
      if (nHeightSrc < 1) return false;
      HDC dc = CreateCompatibleDC(NULL);
      HBITMAP bitmap = CreateBitmap(nWidthSrc, nHeightSrc, 1, GetDeviceCaps(dc,
      BITSPIXEL), NULL);
      if (bitmap == NULL)
       {
                DeleteDC(dc);    
                return false;
        }
     
    HBITMAP oldBitmap = (HBITMAP)SelectObject(dc, bitmap);
    if (!BitBlt(dc, 0, 0, nWidthSrc, nHeightSrc, dcSrc, nXOriginSrc,
                     nYOriginSrc, SRCCOPY))
    {
               SelectObject(dc, oldBitmap); 
               DeleteObject(bitmap);        
         DeleteDC(dc);                
         return false;
    }
       
    HDC maskDC = CreateCompatibleDC(NULL);
     HBITMAP maskBitmap = CreateBitmap(nWidthSrc, nHeightSrc, 1, 1, NULL);
 if (maskBitmap == NULL)
      {
          SelectObject(dc, oldBitmap); 
           DeleteObject(bitmap);        
           DeleteDC(dc);                
           DeleteDC(maskDC);            
           return false;
       }
       HBITMAP oldMask =  (HBITMAP)SelectObject(maskDC, maskBitmap);
       SetBkColor(maskDC, RGB(0,0,0));
       SetTextColor(maskDC, RGB(255,255,255));
  if (!BitBlt(maskDC, 0,0,nWidthSrc,nHeightSrc,NULL,0,0,BLACKNESS))
       {
              SelectObject(maskDC, oldMask); 
              DeleteObject(maskBitmap);      
              DeleteDC(maskDC);              
              SelectObject(dc, oldBitmap);   
              DeleteObject(bitmap);          
              DeleteDC(dc);                  
              return false;
       }
       SetBkColor(dc, crTransparent);
       BitBlt(maskDC, 0,0,nWidthSrc,nHeightSrc,dc,0,0,SRCINVERT);
      SetBkColor(dc, RGB(0,0,0));
       SetTextColor(dc, RGB(255,255,255));
       BitBlt(dc, 0,0,nWidthSrc,nHeightSrc,maskDC,0,0,SRCAND);
       HDC newMaskDC = CreateCompatibleDC(NULL);
       HBITMAP newMask;
       newMask = CreateBitmap(nWidthDest, nHeightDest, 1,
                                                  GetDeviceCaps(newMaskDC, BITSPIXEL), NULL);
  if (newMask == NULL)
       {
              SelectObject(dc, oldBitmap);
              DeleteDC(dc);
              SelectObject(maskDC, oldMask);
              DeleteDC(maskDC);
              DeleteDC(newMaskDC);
              DeleteObject(bitmap);     
              DeleteObject(maskBitmap); 
              return false;
       }
       SetStretchBltMode(newMaskDC, COLORONCOLOR);
       HBITMAP oldNewMask = (HBITMAP) SelectObject(newMaskDC, newMask);
       StretchBlt(newMaskDC, 0, 0, nWidthDest, nHeightDest, maskDC, 0, 0,
                    nWidthSrc, nHeightSrc, SRCCOPY);
       SelectObject(maskDC, oldMask);
       DeleteDC(maskDC);
       DeleteObject(maskBitmap); 
       HDC newImageDC = CreateCompatibleDC(NULL);
       HBITMAP newImage = CreateBitmap(nWidthDest, nHeightDest, 1,
        GetDeviceCaps(newMaskDC, BITSPIXEL), NULL);
  if (newImage == NULL)
       {
              SelectObject(dc, oldBitmap);
              DeleteDC(dc);
              DeleteDC(newMaskDC);
              DeleteObject(bitmap);     
              return false;
       }
       HBITMAP oldNewImage = (HBITMAP)SelectObject(newImageDC, newImage);
       StretchBlt(newImageDC, 0, 0, nWidthDest, nHeightDest, dc, 0, 0, nWidthSrc,
              nHeightSrc, SRCCOPY);
       SelectObject(dc, oldBitmap);
       DeleteDC(dc);
       DeleteObject(bitmap);     
       BitBlt( dcDest, nXOriginDest, nYOriginDest, nWidthDest, nHeightDest,
                          newMaskDC, 0, 0, SRCAND);
       BitBlt( dcDest, nXOriginDest, nYOriginDest, nWidthDest, nHeightDest,
                       newImageDC, 0, 0, SRCPAINT);
       SelectObject(newImageDC, oldNewImage);
       DeleteDC(newImageDC);
       SelectObject(newMaskDC, oldNewMask);
       DeleteDC(newMaskDC);
       DeleteObject(newImage);   
       DeleteObject(newMask);    
       return true;
}

指定掩码图,和掩码图属于不同图片
void DrawTransBitmap( HDC hdcDest,      // 目标DC
                    int nXOriginDest,   // 目标X偏移
                    int nYOriginDest,   // 目标Y偏移
                    int nWidthDest,     // 目标宽度
                    int nHeightDest,    // 目标高度
                    HDC hdcSrc,         // 源DC
                    HDC hdcMask,
                    int nXOriginSrc,    // 源X起点
                    int nYOriginSrc,    // 源Y起点
                    COLORREF crTransparent  // 透明色,COLORREF类型
                    )
{

    HBITMAP hOldImageBMP, hImageBMP = CreateCompatibleBitmap(hdcDest, nWidthDest, nHeightDest);    // 创建兼容位图
     HDC        hImageDC = CreateCompatibleDC(hdcDest);//临时DC 
     hOldImageBMP = (HBITMAP)SelectObject(hImageDC, hImageBMP);
 
    // 将源DC中的位图拷贝到临时DC中,源DC已经载入位图
     BitBlt(hImageDC, 0, 0, nWidthDest, nHeightDest, hdcSrc, nXOriginSrc, nYOriginSrc, SRCCOPY);
     // 设置临时DC的透明色
    SetBkColor(hImageDC, crTransparent);
    // 生成透明区域为黑色，其它区域保持不变的位图
    SetBkColor(hImageDC, RGB(0,0,0));
    SetTextColor(hImageDC, RGB(255,255,255));
    BitBlt(hImageDC, 0, 0, nWidthDest, nHeightDest, hdcMask, 0, 0, SRCAND);
    // 透明部分保持屏幕不变，其它部分变成黑色
    SetBkColor(hdcDest,RGB(255,255,255));
    SetTextColor(hdcDest,RGB(0,0,0));
     BitBlt(hdcDest, nXOriginDest, nYOriginDest, nWidthDest, nHeightDest, hdcMask, 0, 0, SRCAND);
     // "或"运算,生成最终效果
    BitBlt(hdcDest, nXOriginDest, nYOriginDest, nWidthDest, nHeightDest, hImageDC, 0, 0, SRCPAINT);
    // 清理、恢复    
    SelectObject(hImageDC, hOldImageBMP);
    DeleteDC(hImageDC);
    DeleteObject(hImageBMP);
}

指定图片和掩码图同属于一张图片
void DrawTransBitmap(HDC hDC, int nPosX, int nPosY, int nCX, int nCY, HBITMAP hObj)
{
    HDC hMemDC= CreateCompatibleDC(hDC);
    HBITMAP hOldBMP=(HBITMAP)::SelectObject(hMemDC,hObj);
      BitBlt(hDC,nPosX,nPosY,nCX,nCY,    hMemDC,nCX,0,SRCAND);
    BitBlt(hDC,nPosX,nPosY,nCX,nCY,    hMemDC,0,0,SRCPAINT);
    SelectObject(hMemDC,hOldBMP);
    DeleteDC(hMemDC);

} 

HRGN CreateBitmapRgn(int nWidth,int nHeight,HBITMAP hbmp, COLORREF TransColor)
{
        HDC  hmemDC;
        //创建与传入DC兼容的临时DC
        hmemDC = ::CreateCompatibleDC(NULL);        
        HBITMAP hOldBmp = (HBITMAP)::SelectObject(hmemDC,hbmp);
                
        //创建总的窗体区域，初始region为0
        HRGN hrgn;
        hrgn = ::CreateRectRgn(0,0,0,0);           
        
        int y;
        for(y=0;y<nHeight ;y++)
        {
            HRGN rgnTemp; //保存临时region
            
            int iX = 0;
            do
            {
                //跳过透明色找到下一个非透明色的点.
                while (iX < nWidth  && ::GetPixel(hmemDC,iX, y) == TransColor)
                    iX++;
                
                //记住这个起始点
                int iLeftX = iX;
                
                //寻找下个透明色的点
                while (iX < nWidth  && ::GetPixel(hmemDC,iX, y) != TransColor)
                    ++iX;
                
                //创建一个包含起点与重点间高为1像素的临时“region”
                rgnTemp=::CreateRectRgn(iLeftX, y, iX, y+1);
                
                //合并到主"region".
                CombineRgn( hrgn,hrgn,rgnTemp, RGN_OR);
                
                //删除临时"region",否则下次创建时和出错
                ::DeleteObject(rgnTemp);
            }while(iX <nWidth );
            iX = 0;
        }
        ::SelectObject(hmemDC,hOldBmp);