Make specifying minimal size for "unknown" XRC controls work.

At least since the changes of r44456 (see #8378), minimal size specified in
the XRC for unknown controls didn't have any effect as it was set on
wxUnknownControlContainer itself and was overridden by the subsequent call to
SetSizerAndFit() which reset the minimal size to the best size of the control
contained in it, meaning that it was impossible to make this contained control
bigger by specifying min size greater than its best size in the XRC.

Fix this by honouring both the min size of the container and of the control
contained in it (and do the same thing for the max size for good measure).
To avoid not totally obvious interaction of overriding GetMinSize() and
DoGetBestClientSize() with sizer code, also position the child control
manually instead of using a sizer for it, it's an overkill for such a simple
case anyhow.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78359 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/xrc/xh_unkwn.cpp

@@ -22,7 +22,6 @@
     #include "wx/log.h"
     #include "wx/window.h"
     #include "wx/panel.h"
-    #include "wx/sizer.h"
 #endif
 
 
@@ -39,7 +38,8 @@ public:
         // from the XRC if anything.
         : wxPanel(parent, id, pos, size, style | wxTAB_TRAVERSAL | wxNO_BORDER,
                   controlName + wxT("_container")),
-          m_controlName(controlName), m_controlAdded(false)
+          m_controlName(controlName),
+          m_control(NULL)
     {
         m_bg = GetBackgroundColour();
         SetBackgroundColour(wxColour(255, 0, 255));
@@ -48,33 +48,77 @@ public:
     virtual void AddChild(wxWindowBase *child) wxOVERRIDE;
     virtual void RemoveChild(wxWindowBase *child) wxOVERRIDE;
 
+
+    // Ensure that setting the min or max size both for this window itself (as
+    // happens when the XRC contains the corresponding elements) or for the
+    // control contained in it works as expected, i.e. the larger/smaller of
+    // the sizes is used to satisfy both windows invariants.
+
+    virtual wxSize GetMinSize() const wxOVERRIDE
+    {
+        wxSize size = wxPanel::GetMinSize();
+        if ( m_control )
+            size.IncTo(m_control->GetMinSize());
+
+        return size;
+    }
+
+    virtual wxSize GetMaxSize() const wxOVERRIDE
+    {
+        wxSize size = wxPanel::GetMaxSize();
+        if ( m_control )
+            size.DecToIfSpecified(m_control->GetMaxSize());
+
+        return size;
+    }
+
 protected:
+    virtual wxSize DoGetBestClientSize() const wxOVERRIDE
+    {
+        // We don't have any natural best size when we're empty, so just return
+        // the minimal valid size in this case.
+        return m_control ? m_control->GetBestSize() : wxSize(1, 1);
+    }
+
+private:
+    void OnSize(wxSizeEvent& event)
+    {
+        if ( m_control )
+            m_control->SetSize(wxRect(event.GetSize()));
+    }
+
     wxString m_controlName;
-    bool m_controlAdded;
+    wxWindowBase *m_control;
     wxColour m_bg;
+
+    wxDECLARE_EVENT_TABLE();
 };
 
+wxBEGIN_EVENT_TABLE(wxUnknownControlContainer, wxPanel)
+    EVT_SIZE(wxUnknownControlContainer::OnSize)
+wxEND_EVENT_TABLE()
+
 void wxUnknownControlContainer::AddChild(wxWindowBase *child)
 {
-    wxASSERT_MSG( !m_controlAdded, wxT("Couldn't add two unknown controls to the same container!") );
+    wxASSERT_MSG( !m_control, wxT("Couldn't add two unknown controls to the same container!") );
 
     wxPanel::AddChild(child);
 
     SetBackgroundColour(m_bg);
     child->SetName(m_controlName);
     child->SetId(wxXmlResource::GetXRCID(m_controlName));
-    m_controlAdded = true;
+    m_control = child;
 
-    wxSizer *sizer = new wxBoxSizer(wxHORIZONTAL);
-    sizer->Add((wxWindow*)child, 1, wxEXPAND);
-    SetSizerAndFit(sizer);
+    InvalidateBestSize();
+    child->SetSize(wxRect(GetClientSize()));
 }
 
 void wxUnknownControlContainer::RemoveChild(wxWindowBase *child)
 {
     wxPanel::RemoveChild(child);
-    m_controlAdded = false;
-    GetSizer()->Detach((wxWindow*)child);
+    m_control = NULL;
+
+    InvalidateBestSize();
 }