transparent CStatic

// Method 1:class CTransparentStatic : public CStatic{DECLARE_DYNAMIC(CTransparentStatic)public:CTransparentStatic();virtual ~CTransparentStatic();protected: afx_msg LRESULT OnSetText(WPARAM,LPARAM); afx_msg HBRUSH CtlColor(CDC* /*pDC*/, UINT /*nCtlColor*/); DECLARE_MESSAGE_MAP()};#include "TransparentStatic.h"// CTransparentStaticIMPLEMENT_DYNAMIC(CTransparentStatic, CStatic)CTransparentStatic::CTransparentStatic(){}CTransparentStatic::~CTransparentStatic(){}BEGIN_MESSAGE_MAP(CTransparentStatic, CStatic) ON_MESSAGE(WM_SETTEXT,OnSetText) ON_WM_CTLCOLOR_REFLECT()END_MESSAGE_MAP()// CTransparentStatic message handlersLRESULT CTransparentStatic::OnSetText(WPARAM wParam,LPARAM lParam){ LRESULT Result = Default(); CRect Rect; GetWindowRect(&Rect); GetParent()->ScreenToClient(&Rect); GetParent()->InvalidateRect(&Rect); //GetParent()->UpdateWindow(); return Result;}HBRUSH CTransparentStatic::CtlColor(CDC* pDC, UINT /*nCtlColor*/){ pDC->SetBkMode(TRANSPARENT); return (HBRUSH)GetStockObject(NULL_BRUSH);}

 

// Method 2:class CTransparentStatic2 : public CStatic{DECLARE_DYNAMIC(CTransparentStatic2)public:CTransparentStatic2();virtual ~CTransparentStatic2();protected: afx_msg LRESULT OnSetText(WPARAM,LPARAM); afx_msg HBRUSH CtlColor(CDC* /*pDC*/, UINT /*nCtlColor*/); afx_msg BOOL OnEraseBkgnd(CDC* pDC);DECLARE_MESSAGE_MAP()private: CBitmap m_Bmp;};#include "TransparentStatic2.h"// CTransparentStatic2IMPLEMENT_DYNAMIC(CTransparentStatic2, CStatic)CTransparentStatic2::CTransparentStatic2(){}CTransparentStatic2::~CTransparentStatic2(){}BEGIN_MESSAGE_MAP(CTransparentStatic2, CStatic) ON_MESSAGE(WM_SETTEXT,OnSetText) ON_WM_CTLCOLOR_REFLECT() ON_WM_ERASEBKGND()END_MESSAGE_MAP()// CTransparentStatic2 message handlersLRESULT CTransparentStatic2::OnSetText(WPARAM wParam,LPARAM lParam){ LRESULT Result = Default(); //call default base function. Invalidate(); //UpdateWindow(); return Result;}HBRUSH CTransparentStatic2::CtlColor(CDC* pDC, UINT /*nCtlColor*/){ pDC->SetBkMode(TRANSPARENT); return (HBRUSH)GetStockObject(NULL_BRUSH);}BOOL CTransparentStatic2::OnEraseBkgnd(CDC* pDC){ if (m_Bmp.GetSafeHandle() == NULL) { CRect Rect; GetWindowRect(&Rect); CWnd *pParent = GetParent(); ASSERT(pParent); pParent->ScreenToClient(&Rect); //convert our corrdinates to our parents // copy what's on the parents at this point // This DC is not the same with the pDC in the function parameter. CDC *pDC = pParent->GetDC(); CDC MemDC; MemDC.CreateCompatibleDC(pDC); m_Bmp.CreateCompatibleBitmap(pDC,Rect.Width(),Rect.Height()); CBitmap *pOldBmp = MemDC.SelectObject(&m_Bmp); // BitBlt the bitmap to the memdc, it means that copy the parent's background to the MemDc. // so the MemDC keep the background. MemDC.BitBlt(0,0,Rect.Width(),Rect.Height(),pDC,Rect.left,Rect.top,SRCCOPY); MemDC.SelectObject(pOldBmp); pParent->ReleaseDC(pDC); } else //copy what we copied off the parent the first time back onto the parent { CRect Rect; GetClientRect(Rect); CDC MemDC; MemDC.CreateCompatibleDC(pDC); CBitmap *pOldBmp = MemDC.SelectObject(&m_Bmp); // This pDC is the DC of the control itself(in the function's parameter), not its parent's DC. pDC->BitBlt(0,0,Rect.Width(),Rect.Height(),&MemDC,0,0,SRCCOPY); MemDC.SelectObject(pOldBmp); } return TRUE;}

 

These two methods can both implement a transparent CStatic.

But the second one can redunce flicker and flash.

 

I had added more comments to the secnod one to make it more easy the understand.