X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/54753c3d75cce7721667aef855fe30a0f90dcedd..ba0cf6af6d19a7a91ed5087f20bf9b93b7a4f911:/src/msw/window.cpp

diff --git a/src/msw/window.cpp b/src/msw/window.cpp
index c614dca82d..6cef9564b7 100644
--- a/src/msw/window.cpp
+++ b/src/msw/window.cpp
@@ -5109,11 +5109,9 @@ bool wxWindowMSW::HandleExitSizeMove()
     return HandleWindowEvent(event);
 }
 
-bool wxWindowMSW::HandleSize(int WXUNUSED(w), int WXUNUSED(h), WXUINT wParam)
+bool wxWindowMSW::BeginRepositioningChildren()
 {
 #if wxUSE_DEFERRED_SIZING
-    // when we resize this window, its children are probably going to be
-    // repositioned as well, prepare to use DeferWindowPos() for them
     int numChildren = 0;
     for ( HWND child = ::GetWindow(GetHwndOf(this), GW_CHILD);
           child;
@@ -5122,23 +5120,60 @@ bool wxWindowMSW::HandleSize(int WXUNUSED(w), int WXUNUSED(h), WXUINT wParam)
         numChildren ++;
     }
 
+    // Nothing is gained by deferring the repositioning of a single child.
+    if ( numChildren < 2 )
+        return false;
+
     // Protect against valid m_hDWP being overwritten
-    bool useDefer = false;
+    if ( m_hDWP )
+        return false;
 
-    if ( numChildren > 1 )
+    m_hDWP = (WXHANDLE)::BeginDeferWindowPos(numChildren);
+    if ( !m_hDWP )
     {
-        if (!m_hDWP)
-        {
-            m_hDWP = (WXHANDLE)::BeginDeferWindowPos(numChildren);
-            if ( !m_hDWP )
-            {
-                wxLogLastError(wxT("BeginDeferWindowPos"));
-            }
-            if (m_hDWP)
-                useDefer = true;
-        }
+        wxLogLastError(wxT("BeginDeferWindowPos"));
+        return false;
     }
+
+    // Return true to indicate that EndDeferWindowPos() should be called.
+    return true;
 #endif // wxUSE_DEFERRED_SIZING
+}
+
+void wxWindowMSW::EndRepositioningChildren()
+{
+#if wxUSE_DEFERRED_SIZING
+    wxASSERT_MSG( m_hDWP, wxS("Shouldn't be called") );
+
+    // reset m_hDWP to NULL so that child windows don't try to use our
+    // m_hDWP after we call EndDeferWindowPos() on it (this shouldn't
+    // happen anyhow normally but who knows what weird flow of control we
+    // may have depending on what the users EVT_SIZE handler does...)
+    HDWP hDWP = (HDWP)m_hDWP;
+    m_hDWP = NULL;
+
+    // do put all child controls in place at once
+    if ( !::EndDeferWindowPos(hDWP) )
+    {
+        wxLogLastError(wxT("EndDeferWindowPos"));
+    }
+
+    // Reset our children's pending pos/size values.
+    for ( wxWindowList::compatibility_iterator node = GetChildren().GetFirst();
+          node;
+          node = node->GetNext() )
+    {
+        wxWindowMSW * const child = node->GetData();
+        child->MSWEndDeferWindowPos();
+    }
+#endif // wxUSE_DEFERRED_SIZING
+}
+
+bool wxWindowMSW::HandleSize(int WXUNUSED(w), int WXUNUSED(h), WXUINT wParam)
+{
+    // when we resize this window, its children are probably going to be
+    // repositioned as well, prepare to use DeferWindowPos() for them
+    ChildrenRepositioningGuard repositionGuard(this);
 
     // update this window size
     bool processed = false;
@@ -5171,34 +5206,6 @@ bool wxWindowMSW::HandleSize(int WXUNUSED(w), int WXUNUSED(h), WXUINT wParam)
             processed = HandleWindowEvent(event);
     }
 
-#if wxUSE_DEFERRED_SIZING
-    // and finally change the positions of all child windows at once
-    if ( useDefer && m_hDWP )
-    {
-        // reset m_hDWP to NULL so that child windows don't try to use our
-        // m_hDWP after we call EndDeferWindowPos() on it (this shouldn't
-        // happen anyhow normally but who knows what weird flow of control we
-        // may have depending on what the users EVT_SIZE handler does...)
-        HDWP hDWP = (HDWP)m_hDWP;
-        m_hDWP = NULL;
-
-        // do put all child controls in place at once
-        if ( !::EndDeferWindowPos(hDWP) )
-        {
-            wxLogLastError(wxT("EndDeferWindowPos"));
-        }
-
-        // Reset our children's pending pos/size values.
-        for ( wxWindowList::compatibility_iterator node = GetChildren().GetFirst();
-              node;
-              node = node->GetNext() )
-        {
-            wxWindowMSW * const child = node->GetData();
-            child->MSWEndDeferWindowPos();
-        }
-    }
-#endif // wxUSE_DEFERRED_SIZING
-
     return processed;
 }