透明ToolTip

void CSBoxToolTip::ShowTip(LPCTSTR lpszTipText){if(lpszTipText==NULL) return;CString strTip(lpszTipText);if(m_hTextBitmap)DeleteObject(m_hTextBitmap);CDC *pDC = GetDC(); CDC MemDC;MemDC.CreateCompatibleDC(pDC);MemDC.SetBkMode(TRANSPARENT);MemDC.SetTextColor(m_crText);HGDIOBJ pOldFont = MemDC.SelectObject(&m_fontText);CSize sz = MemDC.GetTextExtent(strTip);int reminder = sz.cx % 4;sz.cx += 4 - reminder;MoveWindow(0,0,sz.cx+8,sz.cy+8);BITMAPINFOHEADER stBmpInfoHeader = { 0 }; int nBytesPerLine = ((sz.cx * 32 + 31) & (~31)) >> 3; //(sz.cx*32+31)/32*4;stBmpInfoHeader.biSize = sizeof(BITMAPINFOHEADER); stBmpInfoHeader.biWidth = sz.cx; stBmpInfoHeader.biHeight = sz.cy; stBmpInfoHeader.biPlanes = 1; stBmpInfoHeader.biBitCount = 32; stBmpInfoHeader.biCompression = BI_RGB; stBmpInfoHeader.biClrUsed = 0; stBmpInfoHeader.biSizeImage = nBytesPerLine * sz.cy; PVOID pvBits = NULL; m_hTextBitmap = ::CreateDIBSection(NULL, (PBITMAPINFO)&stBmpInfoHeader, DIB_RGB_COLORS, &pvBits, NULL, 0);ASSERT(m_hTextBitmap != NULL);memset(pvBits,0,sz.cx*4*sz.cy);HGDIOBJ hbmpOld = MemDC.SelectObject( m_hTextBitmap );MemDC.DrawText(strTip,strTip.GetLength(),CRect(0,0,sz.cx,sz.cy),DT_CENTER);POINT ptSrc = { 0, 0};POINT ptWinPos = { 0, 0};ClientToScreen(&ptWinPos);SIZE szWin = { sz.cx, sz.cy};BYTE SourceConstantAlpha = 255;BLENDFUNCTION stBlend = { AC_SRC_OVER, 0, SourceConstantAlpha, AC_SRC_ALPHA };BOOL b = UpdateLayeredWindow( pDC,&ptWinPos,&szWin,&MemDC,&ptSrc,0,&stBlend,ULW_ALPHA);MemDC.SelectObject(hbmpOld); MemDC.SelectObject(pOldFont);ReleaseDC(&MemDC);ReleaseDC(pDC);}

 

创建窗口

BOOL CSBoxToolTip::Create(const CRect& rect, CWnd* pParentWnd){HWND hParent = NULL;if(pParentWnd)hParent = pParentWnd->m_hWnd;LPCTSTR lpszClassName = AfxRegisterWndClass(CS_VREDRAW | CS_HREDRAW,::LoadCursor(NULL, IDC_ARROW),(HBRUSH) ::GetStockObject(NULL_BRUSH),::LoadIcon(NULL, IDI_APPLICATION));BOOL bRet = CreateEx(WS_EX_TRANSPARENT|WS_EX_LAYERED,lpszClassName,_T("SBoxToolTip"),WS_POPUP,rect.left,rect.top,rect.Width(),rect.Height(),hParent,NULL);return bRet;}