TransparentBitmap

 // 创建反转的目标屏蔽码

   BitBlt(hBack, 0, 0, ptSize.x, ptSize.y, hObject, 0, 0, NOTSRCCOPY);

   // 拷贝主DC的背景到目标DC

   BitBlt(hMem, 0, 0, ptSize.x, ptSize.y, hdc, xStart, yStart, SRCCOPY);

   // 屏蔽位图的显示区

   BitBlt(hMem, 0, 0, ptSize.x, ptSize.y, hObject, 0, 0, SRCAND);

   // 屏蔽位图中的透明色

   BitBlt(hTemp, 0, 0, ptSize.x, ptSize.y, hBack, 0, 0, SRCAND);

   // 将位图与目标DC的背景左异或操作

   BitBlt(hMem, 0, 0, ptSize.x, ptSize.y, hTemp, 0, 0, SRCPAINT);

   // 拷贝目标到屏幕上

   StretchBlt(hdc, xStart, yStart, ptSize.x+xadd, ptSize.y+yadd, hMem, 0, 0, ptSize.x, ptSize.y,SRCCOPY);

   // 恢复原始位图

   BitBlt(hTemp, 0, 0, ptSize.x, ptSize.y, hSave, 0, 0, SRCCOPY);

 

   // 删除临时内存位图

   DeleteObject(SelectObject(hBack, OldbmBack));

   DeleteObject(SelectObject(hObject, OldbmObject));

   DeleteObject(SelectObject(hMem, OldbmMem));

   DeleteObject(SelectObject(hSave, OldbmSave));

 

   // 删除临时内存DC

   DeleteDC(hMem);

   DeleteDC(hBack);

   DeleteDC(hObject);

   DeleteDC(hSave);

   DeleteDC(hTemp);

}