[Effective WX] 理解wxWindow与wxSizer的关系

wxWindow与wxSizer
每个wxWindow都有一个m_contaningSizer（包含这个wxWindow窗口），还有一个m_windowSizer（这个窗口所包含的顶层wxSizer）。

设置包含这个window的sizer

void wxWindowBase::SetContainingSizer(wxSizer* sizer){// adding a window to a sizer twice is going to result in fatal and// hard to debug problems later because when deleting the second// associated wxSizerItem we're going to dereference a dangling// pointer; so try to detect this as early as possiblewxASSERT_MSG( !sizer || m_containingSizer != sizer,_T("Adding a window to the same sizer twice?") );m_containingSizer = sizer;}

设置这个窗口包含的顶层sizer

void wxWindowBase::SetSizer(wxSizer *sizer, bool deleteOld){if ( sizer == m_windowSizer)return;</em>if ( m_windowSizer ){m_windowSizer->SetContainingWindow(NULL);if ( deleteOld )delete m_windowSizer;}m_windowSizer = sizer;if ( m_windowSizer ){m_windowSizer->SetContainingWindow((wxWindow *)this);}SetAutoLayout(m_windowSizer != NULL);}

窗口的Layout函数
layout这个窗口时，如果存在顶层sizer，就会调用这个sizer的Layout(in SetDimension函数中）。

bool wxWindowBase::Layout(){// If there is a sizer, use it instead of the constraintsif ( GetSizer() ){int w = 0, h = 0;GetVirtualSize(&w, &h);GetSizer()->SetDimension( 0, 0, w, h );}#if wxUSE_CONSTRAINTSelse{SatisfyConstraints(); // Find the right constraints valuesSetConstraintSizes(); // Recursively set the real window sizes}#endifreturn true;}

window的virtual size是client sizer和virtual Size变量的较大值。一般的window都是client size和virtual size变量一样大，除了scroll window类似的窗口。

wxSize wxWindowBase::DoGetVirtualSize() const{// we should use the entire client area so if it is greater than our// virtual size, expand it to fit (otherwise if the window is big enough we// wouldn't be using parts of it)wxSize size = GetClientSize();if ( m_virtualSize.x > size.x )size.x = m_virtualSize.x;if ( m_virtualSize.y >= size.y )size.y = m_virtualSize.y;return size;}