Added always-unsplittable style option (wxSP_PERMIT_UNSPLIT)

Added visual feedback on limits for sash-drag
(Fix of previous broken behaviour: now unplits only if min pane size == 0 or
 if always-unsplittable style flag is used.)


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@2552 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/generic/splitter.h

@@ -181,12 +181,14 @@ public:
 protected:
     // our event handlers
     void OnSashPosChanged(wxSplitterEvent& event);
+    void OnSashPosChanging(wxSplitterEvent& event);
     void OnDoubleClick(wxSplitterEvent& event);
     void OnUnsplitEvent(wxSplitterEvent& event);
 
     void SendUnsplitEvent(wxWindow *winRemoved);
 
     int         m_splitMode;
+    bool        m_permitUnsplitAlways;
     wxWindow*   m_windowOne;
     wxWindow*   m_windowTwo;
     int         m_dragMode;
@@ -237,14 +239,16 @@ public:
     // all
     void SetSashPosition(int pos)
     {
-        wxASSERT( GetEventType() == wxEVT_COMMAND_SPLITTER_SASH_POS_CHANGED );
+        wxASSERT( GetEventType() == wxEVT_COMMAND_SPLITTER_SASH_POS_CHANGED
+                || GetEventType() == wxEVT_COMMAND_SPLITTER_SASH_POS_CHANGING);
 
         m_data.pos = pos;
     }
 
     int GetSashPosition() const
     {
-        wxASSERT( GetEventType() == wxEVT_COMMAND_SPLITTER_SASH_POS_CHANGED );
+        wxASSERT( GetEventType() == wxEVT_COMMAND_SPLITTER_SASH_POS_CHANGED
+                || GetEventType() == wxEVT_COMMAND_SPLITTER_SASH_POS_CHANGING);
 
         return m_data.pos;
     }
@@ -300,9 +304,18 @@ typedef void (wxEvtHandler::*wxSplitterEventFunction)(wxSplitterEvent&);
     NULL                                                                    \
   },
 
-#define EVT_SPLITTER_DCLICK(id, fn)                                   \
+#define EVT_SPLITTER_SASH_POS_CHANGING(id, fn)                              \
   {                                                                         \
-    wxEVT_COMMAND_SPLITTER_DOUBLECLICKED,                                    \
+    wxEVT_COMMAND_SPLITTER_SASH_POS_CHANGING,                               \
+    id,                                                                     \
+    -1,                                                                     \
+    (wxObjectEventFunction)(wxEventFunction)(wxSplitterEventFunction) &fn,  \
+    NULL                                                                    \
+  },
+
+#define EVT_SPLITTER_DCLICK(id, fn)                                         \
+  {                                                                         \
+    wxEVT_COMMAND_SPLITTER_DOUBLECLICKED,                                   \
     id,                                                                     \
     -1,                                                                     \
     (wxObjectEventFunction)(wxEventFunction)(wxSplitterEventFunction) &fn,  \

src/generic/splitter.cpp

@@ -40,6 +40,9 @@ BEGIN_EVENT_TABLE(wxSplitterWindow, wxWindow)
     EVT_MOUSE_EVENTS(wxSplitterWindow::OnMouseEvent)
 
     EVT_SPLITTER_SASH_POS_CHANGED(-1, wxSplitterWindow::OnSashPosChanged)
+    // NB: we borrow OnSashPosChanged for purposes of
+    // EVT_SPLITTER_SASH_POS_CHANGING since default implementation is identical
+    EVT_SPLITTER_SASH_POS_CHANGING(-1, wxSplitterWindow::OnSashPosChanged)
     EVT_SPLITTER_DCLICK(-1,           wxSplitterWindow::OnDoubleClick)
     EVT_SPLITTER_UNSPLIT(-1,          wxSplitterWindow::OnUnsplitEvent)
 END_EVENT_TABLE()
@@ -48,6 +51,7 @@ END_EVENT_TABLE()
 wxSplitterWindow::wxSplitterWindow()
 {
     m_splitMode = wxSPLIT_VERTICAL;
+    m_permitUnsplitAlways = FALSE;
     m_windowOne = (wxWindow *) NULL;
     m_windowTwo = (wxWindow *) NULL;
     m_dragMode = wxSPLIT_DRAG_NONE;
@@ -78,6 +82,7 @@ wxSplitterWindow::wxSplitterWindow(wxWindow *parent, wxWindowID id,
                 : wxWindow(parent, id, pos, size, style, name)
 {
     m_splitMode = wxSPLIT_VERTICAL;
+    m_permitUnsplitAlways = (style & wxSP_PERMIT_UNSPLIT) != 0;
     m_windowOne = (wxWindow *) NULL;
     m_windowTwo = (wxWindow *) NULL;
     m_dragMode = wxSPLIT_DRAG_NONE;
@@ -212,22 +217,31 @@ void wxSplitterWindow::OnMouseEvent(wxMouseEvent& event)
             }
         }
 
-        if ( new_sash_position == 0 )
+        if ( m_permitUnsplitAlways
+                || m_minimumPaneSize == 0 )
         {
-            // We remove the first window from the view
+            // Deal with possible unsplit scenarios
-            wxWindow *removedWindow = m_windowOne;
+            if ( new_sash_position == 0 )
-            m_windowOne = m_windowTwo;
+            {
-            m_windowTwo = (wxWindow *) NULL;
+                // We remove the first window from the view
-            SendUnsplitEvent(removedWindow);
+                wxWindow *removedWindow = m_windowOne;
-            m_sashPosition = 0;
+                m_windowOne = m_windowTwo;
-        }
+                m_windowTwo = (wxWindow *) NULL;
-        else if ( new_sash_position == window_size )
+                SendUnsplitEvent(removedWindow);
-        {
+                m_sashPosition = 0;
-            // We remove the second window from the view
+            }
-            wxWindow *removedWindow = m_windowTwo;
+            else if ( new_sash_position == window_size )
-            m_windowTwo = (wxWindow *) NULL;
+            {
-            SendUnsplitEvent(removedWindow);
+                // We remove the second window from the view
-            m_sashPosition = 0;
+                wxWindow *removedWindow = m_windowTwo;
+                m_windowTwo = (wxWindow *) NULL;
+                SendUnsplitEvent(removedWindow);
+                m_sashPosition = 0;
+            }
+            else
+            {
+                m_sashPosition = new_sash_position;
+            }
         }
         else
         {
@@ -260,9 +274,39 @@ void wxSplitterWindow::OnMouseEvent(wxMouseEvent& event)
     }
     else if (event.Dragging() && (m_dragMode == wxSPLIT_DRAG_DRAGGING)) 
     {
+        // Obtain window size. We are only interested in the dimension the sash
+        // splits up
+        int new_sash_position =
+            (int) ( m_splitMode == wxSPLIT_VERTICAL ? x : y );
+
+        wxSplitterEvent eventSplitter(wxEVT_COMMAND_SPLITTER_SASH_POS_CHANGING,
+                                      this);
+        eventSplitter.m_data.pos = new_sash_position;
+        if ( GetEventHandler()->ProcessEvent(eventSplitter) )
+        {
+            new_sash_position = eventSplitter.GetSashPosition();
+            if ( new_sash_position == -1 )
+            {
+                // change not allowed
+                return;
+            }
+        }
+
         // Erase old tracker
         DrawSashTracker(m_oldX, m_oldY);
 
+        if (m_splitMode == wxSPLIT_VERTICAL)
+            x = new_sash_position;
+        else
+            y = new_sash_position;
+
+        if (new_sash_position != -1)
+        {
+            // Only modify if permitted
+            m_oldX = x;
+            m_oldY = y;
+        }
+
 #ifdef __WXMSW__
         // As we captured the mouse, we may get the mouse events from outside
         // our window - for example, negative values in x, y. This has a weird
@@ -270,9 +314,6 @@ void wxSplitterWindow::OnMouseEvent(wxMouseEvent& event)
         // signed ones other times: the coordinates turn as big positive
         // numbers and so the sash is drawn on the *right* side of the window
         // instead of the left (or bottom instead of top). Correct this.
-        m_oldX = x;
-        m_oldY = y;
-
         if ( (short)m_oldX < 0 )
             m_oldX = 0;
         if ( (short)m_oldY < 0 )
@@ -751,26 +792,32 @@ void wxSplitterWindow::OnSashPosChanged(wxSplitterEvent& event)
     GetClientSize(&w, &h);
     int window_size = (m_splitMode == wxSPLIT_VERTICAL) ? w : h ;
 
-    if ( newSashPosition <= UNSPLIT_THRESHOLD )
+    bool unsplit_scenario = FALSE;
+    if ( m_permitUnsplitAlways
+            || m_minimumPaneSize == 0 )
     {
-        // threshold top / left check
+        // Do edge detection if unsplit premitted
-        newSashPosition = 0;
+        if ( newSashPosition <= UNSPLIT_THRESHOLD )
-    }
+        {
-    else if ( newSashPosition < m_minimumPaneSize )
+            // threshold top / left check
-    {
+            newSashPosition = 0;
-        // If resultant pane would be too small, enlarge it
+            unsplit_scenario = TRUE;
-        newSashPosition = m_minimumPaneSize;
+        }
+        if ( newSashPosition >= window_size - UNSPLIT_THRESHOLD )
+        {
+            // threshold bottom/right check
+            newSashPosition = window_size;
+            unsplit_scenario = TRUE;
+        }
     }
 
-    if ( newSashPosition >= window_size - UNSPLIT_THRESHOLD )
+    if ( !unsplit_scenario )
-    {
-        // threshold bottom/right check
-        newSashPosition = window_size;
-    }
-    else if ( newSashPosition > window_size - m_minimumPaneSize )
     {
         // If resultant pane would be too small, enlarge it
-        newSashPosition = window_size - m_minimumPaneSize;
+        if ( newSashPosition < m_minimumPaneSize )
+            newSashPosition = m_minimumPaneSize;
+        if ( newSashPosition > window_size - m_minimumPaneSize )
+            newSashPosition = window_size - m_minimumPaneSize;
     }
 
     // If the result is out of bounds it means minimum size is too big,
@@ -794,7 +841,8 @@ void wxSplitterWindow::OnDoubleClick(wxSplitterEvent& event)
     // for compatibility, call the virtual function
     OnDoubleClickSash(event.GetX(), event.GetY());
 
-    if ( GetMinimumPaneSize() == 0 )
+    if ( GetMinimumPaneSize() == 0
+        || m_permitUnsplitAlways)
     {
         Unsplit();
     }