fix another memory leak in SetCommand() (coverity checker CID 52)

[wxWidgets.git] / src / richtext / richtextctrl.cpp

diff --git a/src/richtext/richtextctrl.cpp b/src/richtext/richtextctrl.cpp
index 297a3dea4f1252fad8038099e9ca971b74470966..04712e599178cee6241d5ef1a86b97bfbd7100ba 100644 (file)
--- a/src/richtext/richtextctrl.cpp
+++ b/src/richtext/richtextctrl.cpp
@@ -16,21 +16,19 @@
   #pragma hdrstop
 #endif
 
   #pragma hdrstop
 #endif
 

+#if wxUSE_RICHTEXT
+
+#include "wx/richtext/richtextctrl.h"
+

 #ifndef WX_PRECOMP
   #include "wx/wx.h"
 #endif
 
 #ifndef WX_PRECOMP
   #include "wx/wx.h"
 #endif
 

-#include "wx/image.h"
-
-#if wxUSE_RICHTEXT
-

 #include "wx/textfile.h"
 #include "wx/ffile.h"
 #include "wx/settings.h"
 #include "wx/filename.h"
 #include "wx/dcbuffer.h"
 #include "wx/textfile.h"
 #include "wx/ffile.h"
 #include "wx/settings.h"
 #include "wx/filename.h"
 #include "wx/dcbuffer.h"

-
-#include "wx/richtext/richtextctrl.h"

 #include "wx/arrimpl.cpp"
 
 DEFINE_EVENT_TYPE(wxEVT_COMMAND_RICHTEXT_ITEM_SELECTED)
 #include "wx/arrimpl.cpp"
 
 DEFINE_EVENT_TYPE(wxEVT_COMMAND_RICHTEXT_ITEM_SELECTED)


@@ -187,14 +185,14 @@ void wxRichTextCtrl::Freeze()
 }
 
 /// Call Thaw to refresh
 }
 
 /// Call Thaw to refresh

-void wxRichTextCtrl::Thaw(bool refresh)
+void wxRichTextCtrl::Thaw()

 {
     m_freezeCount --;
 
 {
     m_freezeCount --;
 

-    if (m_freezeCount == 0 && refresh)
+    if (m_freezeCount == 0)

     {
         SetupScrollbars();
     {
         SetupScrollbars();

-        Refresh();
+        Refresh(false);

     }
 }
 
     }
 }
 


@@ -210,7 +208,7 @@ void wxRichTextCtrl::Clear()
     if (m_freezeCount == 0)
     {
         SetupScrollbars();
     if (m_freezeCount == 0)
     {
         SetupScrollbars();

-        Refresh();
+        Refresh(false);

     }
     SendUpdateEvent();
 }
     }
     SendUpdateEvent();
 }


@@ -224,19 +222,19 @@ void wxRichTextCtrl::OnPaint(wxPaintEvent& WXUNUSED(event))
     {
         wxBufferedPaintDC dc(this, m_bufferBitmap);
         //wxLogDebug(wxT("OnPaint"));
     {
         wxBufferedPaintDC dc(this, m_bufferBitmap);
         //wxLogDebug(wxT("OnPaint"));

-        
+

         PrepareDC(dc);
         PrepareDC(dc);

-        
+

         if (m_freezeCount > 0)
             return;
         if (m_freezeCount > 0)
             return;

-        
+

         dc.SetFont(GetFont());
         dc.SetFont(GetFont());

-        
+

         // Paint the background
         PaintBackground(dc);
         // Paint the background
         PaintBackground(dc);

-        
+

         wxRegion dirtyRegion = GetUpdateRegion();
         wxRegion dirtyRegion = GetUpdateRegion();

-        
+

         wxRect drawingArea(GetLogicalPoint(wxPoint(0, 0)), GetClientSize());
         wxRect availableSpace(GetClientSize());
         if (GetBuffer().GetDirty())
         wxRect drawingArea(GetLogicalPoint(wxPoint(0, 0)), GetClientSize());
         wxRect availableSpace(GetClientSize());
         if (GetBuffer().GetDirty())


@@ -245,7 +243,7 @@ void wxRichTextCtrl::OnPaint(wxPaintEvent& WXUNUSED(event))
             GetBuffer().SetDirty(false);
             SetupScrollbars();
         }
             GetBuffer().SetDirty(false);
             SetupScrollbars();
         }

-        
+

         GetBuffer().Draw(dc, GetBuffer().GetRange(), GetSelectionRange(), drawingArea, 0 /* descent */, 0 /* flags */);
     }
 
         GetBuffer().Draw(dc, GetBuffer().GetRange(), GetSelectionRange(), drawingArea, 0 /* descent */, 0 /* flags */);
     }
 


@@ -268,7 +266,7 @@ void wxRichTextCtrl::OnSetFocus(wxFocusEvent& WXUNUSED(event))
     PositionCaret();
 
     if (!IsFrozen())
     PositionCaret();
 
     if (!IsFrozen())

-        Refresh();
+        Refresh(false);

 }
 
 void wxRichTextCtrl::OnKillFocus(wxFocusEvent& WXUNUSED(event))
 }
 
 void wxRichTextCtrl::OnKillFocus(wxFocusEvent& WXUNUSED(event))


@@ -276,7 +274,7 @@ void wxRichTextCtrl::OnKillFocus(wxFocusEvent& WXUNUSED(event))
     SetCaret(NULL);
 
     if (!IsFrozen())
     SetCaret(NULL);
 
     if (!IsFrozen())

-        Refresh();
+        Refresh(false);

 }
 
 /// Left-click
 }
 
 /// Left-click


@@ -389,7 +387,7 @@ void wxRichTextCtrl::OnMoveMouse(wxMouseEvent& event)
             SetDefaultStyleToCursorStyle();
 
             if (extendSel)
             SetDefaultStyleToCursorStyle();
 
             if (extendSel)

-                Refresh();
+                Refresh(false);

         }
     }
 }
         }
     }
 }


@@ -435,7 +433,7 @@ void wxRichTextCtrl::OnChar(wxKeyEvent& event)
         event.GetKeyCode() == WXK_NEXT ||
         event.GetKeyCode() == WXK_END)
     {
         event.GetKeyCode() == WXK_NEXT ||
         event.GetKeyCode() == WXK_END)
     {

-        Navigate(event.GetKeyCode(), flags);
+        KeyboardNavigate(event.GetKeyCode(), flags);

     }
     else if (event.GetKeyCode() == WXK_RETURN)
     {
     }
     else if (event.GetKeyCode() == WXK_RETURN)
     {


@@ -456,6 +454,8 @@ void wxRichTextCtrl::OnChar(wxKeyEvent& event)
 
         EndBatchUndo();
         SetDefaultStyleToCursorStyle();
 
         EndBatchUndo();
         SetDefaultStyleToCursorStyle();

+
+        ScrollIntoView(m_caretPosition, WXK_RIGHT);

     }
     else if (event.GetKeyCode() == WXK_BACK)
     {
     }
     else if (event.GetKeyCode() == WXK_BACK)
     {


@@ -485,6 +485,7 @@ void wxRichTextCtrl::OnChar(wxKeyEvent& event)
             SetDefaultStyleToCursorStyle();
         }
 
             SetDefaultStyleToCursorStyle();
         }
 

+        ScrollIntoView(m_caretPosition, WXK_LEFT);

     }
     else if (event.GetKeyCode() == WXK_DELETE)
     {
     }
     else if (event.GetKeyCode() == WXK_DELETE)
     {


@@ -526,6 +527,7 @@ void wxRichTextCtrl::OnChar(wxKeyEvent& event)
         EndBatchUndo();
 
         SetDefaultStyleToCursorStyle();
         EndBatchUndo();
 
         SetDefaultStyleToCursorStyle();

+        ScrollIntoView(m_caretPosition, WXK_RIGHT);

     }
 #if 0
     else
     }
 #if 0
     else


@@ -584,10 +586,9 @@ Adding Shift does the above but starts/extends selection.
 
  */
 
 
  */
 

-bool wxRichTextCtrl::Navigate(int keyCode, int flags)
+bool wxRichTextCtrl::KeyboardNavigate(int keyCode, int flags)

 {
     bool success = false;
 {
     bool success = false;

-    Freeze();

 
     if (keyCode == WXK_RIGHT)
     {
 
     if (keyCode == WXK_RIGHT)
     {


@@ -646,8 +647,6 @@ bool wxRichTextCtrl::Navigate(int keyCode, int flags)
         SetDefaultStyleToCursorStyle();
     }
 
         SetDefaultStyleToCursorStyle();
     }
 

-    Thaw(false);
-

     return success;
 }
 
     return success;
 }
 


@@ -704,7 +703,7 @@ bool wxRichTextCtrl::ScrollIntoView(long position, int keyCode)
     startX = 0;
     startY = startY * ppuY;
 
     startX = 0;
     startY = startY * ppuY;
 

-    int sx, sy;
+    int sx = 0, sy = 0;

     GetVirtualSize(& sx, & sy);
     sx = 0;
     if (ppuY != 0)
     GetVirtualSize(& sx, & sy);
     sx = 0;
     if (ppuY != 0)


@@ -797,7 +796,7 @@ bool wxRichTextCtrl::IsPositionVisible(long pos) const
     startX = 0;
     startY = startY * ppuY;
 
     startX = 0;
     startY = startY * ppuY;
 

-    int sx, sy;
+    int sx = 0, sy = 0;

     GetVirtualSize(& sx, & sy);
     sx = 0;
     if (ppuY != 0)
     GetVirtualSize(& sx, & sy);
     sx = 0;
     if (ppuY != 0)


@@ -939,7 +938,7 @@ bool wxRichTextCtrl::MoveRight(int noPositions, int flags)
         SetDefaultStyleToCursorStyle();
 
         if (extendSel)
         SetDefaultStyleToCursorStyle();
 
         if (extendSel)

-            Refresh();
+            Refresh(false);

         return true;
     }
     else
         return true;
     }
     else


@@ -968,7 +967,7 @@ bool wxRichTextCtrl::MoveLeft(int noPositions, int flags)
         SetDefaultStyleToCursorStyle();
 
         if (extendSel)
         SetDefaultStyleToCursorStyle();
 
         if (extendSel)

-            Refresh();
+            Refresh(false);

         return true;
     }
     else
         return true;
     }
     else


@@ -1059,11 +1058,11 @@ bool wxRichTextCtrl::MoveDown(int noLines, int flags)
         SetDefaultStyleToCursorStyle();
 
         if (extendSel)
         SetDefaultStyleToCursorStyle();
 
         if (extendSel)

-            Refresh();
+            Refresh(false);

         return true;
     }
         return true;
     }

-    else
-        return false;
+
+    return false;

 }
 
 /// Move to the end of the paragraph
 }
 
 /// Move to the end of the paragraph


@@ -1082,7 +1081,7 @@ bool wxRichTextCtrl::MoveToParagraphEnd(int flags)
         SetDefaultStyleToCursorStyle();
 
         if (extendSel)
         SetDefaultStyleToCursorStyle();
 
         if (extendSel)

-            Refresh();
+            Refresh(false);

         return true;
     }
 
         return true;
     }
 


@@ -1105,7 +1104,7 @@ bool wxRichTextCtrl::MoveToParagraphStart(int flags)
         SetDefaultStyleToCursorStyle();
 
         if (extendSel)
         SetDefaultStyleToCursorStyle();
 
         if (extendSel)

-            Refresh();
+            Refresh(false);

         return true;
     }
 
         return true;
     }
 


@@ -1130,7 +1129,7 @@ bool wxRichTextCtrl::MoveToLineEnd(int flags)
         SetDefaultStyleToCursorStyle();
 
         if (extendSel)
         SetDefaultStyleToCursorStyle();
 
         if (extendSel)

-            Refresh();
+            Refresh(false);

         return true;
     }
 
         return true;
     }
 


@@ -1157,7 +1156,7 @@ bool wxRichTextCtrl::MoveToLineStart(int flags)
         SetDefaultStyleToCursorStyle();
 
         if (extendSel)
         SetDefaultStyleToCursorStyle();
 
         if (extendSel)

-            Refresh();
+            Refresh(false);

         return true;
     }
 
         return true;
     }
 


@@ -1178,7 +1177,7 @@ bool wxRichTextCtrl::MoveHome(int flags)
         SetDefaultStyleToCursorStyle();
 
         if (extendSel)
         SetDefaultStyleToCursorStyle();
 
         if (extendSel)

-            Refresh();
+            Refresh(false);

         return true;
     }
     else
         return true;
     }
     else


@@ -1201,7 +1200,7 @@ bool wxRichTextCtrl::MoveEnd(int flags)
         SetDefaultStyleToCursorStyle();
 
         if (extendSel)
         SetDefaultStyleToCursorStyle();
 
         if (extendSel)

-            Refresh();
+            Refresh(false);

         return true;
     }
     else
         return true;
     }
     else


@@ -1242,7 +1241,7 @@ bool wxRichTextCtrl::PageDown(int noPages, int flags)
                 SetDefaultStyleToCursorStyle();
 
                 if (extendSel)
                 SetDefaultStyleToCursorStyle();
 
                 if (extendSel)

-                    Refresh();
+                    Refresh(false);

                 return true;
             }
         }
                 return true;
             }
         }


@@ -1341,7 +1340,7 @@ bool wxRichTextCtrl::WordLeft(int WXUNUSED(n), int flags)
         SetDefaultStyleToCursorStyle();
 
         if (extendSel)
         SetDefaultStyleToCursorStyle();
 
         if (extendSel)

-            Refresh();
+            Refresh(false);

         return true;
     }
 
         return true;
     }
 


@@ -1365,7 +1364,7 @@ bool wxRichTextCtrl::WordRight(int WXUNUSED(n), int flags)
         SetDefaultStyleToCursorStyle();
 
         if (extendSel)
         SetDefaultStyleToCursorStyle();
 
         if (extendSel)

-            Refresh();
+            Refresh(false);

         return true;
     }
 
         return true;
     }
 


@@ -1381,7 +1380,7 @@ void wxRichTextCtrl::OnSize(wxSizeEvent& event)
         m_fullLayoutRequired = true;
         m_fullLayoutTime = wxGetLocalTimeMillis();
         m_fullLayoutSavedPosition = GetFirstVisiblePosition();
         m_fullLayoutRequired = true;
         m_fullLayoutTime = wxGetLocalTimeMillis();
         m_fullLayoutSavedPosition = GetFirstVisiblePosition();

-        Layout(true /* onlyVisibleRect */);
+        LayoutContent(true /* onlyVisibleRect */);

     }
     else
         GetBuffer().Invalidate(wxRICHTEXT_ALL);
     }
     else
         GetBuffer().Invalidate(wxRICHTEXT_ALL);


@@ -1403,7 +1402,7 @@ void wxRichTextCtrl::OnIdle(wxIdleEvent& event)
         m_fullLayoutTime = 0;
         GetBuffer().Invalidate(wxRICHTEXT_ALL);
         ShowPosition(m_fullLayoutSavedPosition);
         m_fullLayoutTime = 0;
         GetBuffer().Invalidate(wxRICHTEXT_ALL);
         ShowPosition(m_fullLayoutSavedPosition);

-        Refresh();
+        Refresh(false);

     }
     event.Skip();
 }
     }
     event.Skip();
 }


@@ -1497,10 +1496,10 @@ bool wxRichTextCtrl::LoadFile(const wxString& filename, int type)
 
     DiscardEdits();
     SetInsertionPoint(0);
 
     DiscardEdits();
     SetInsertionPoint(0);

-    Layout();
+    LayoutContent();

     PositionCaret();
     SetupScrollbars(true);
     PositionCaret();
     SetupScrollbars(true);

-    Refresh();
+    Refresh(false);

     SendUpdateEvent();
 
     if (success)
     SendUpdateEvent();
 
     if (success)


@@ -1582,17 +1581,20 @@ wxString wxRichTextCtrl::GetStringSelection() const
 }
 
 // do the window-specific processing after processing the update event
 }
 
 // do the window-specific processing after processing the update event

+#if !wxRICHTEXT_DERIVES_FROM_TEXTCTRLBASE

 void wxRichTextCtrl::DoUpdateWindowUI(wxUpdateUIEvent& event)
 {
 void wxRichTextCtrl::DoUpdateWindowUI(wxUpdateUIEvent& event)
 {

-    if ( event.GetSetEnabled() )
-        Enable(event.GetEnabled());
+    // call inherited
+    wxWindowBase::DoUpdateWindowUI(event);

 
 

+    // update text

     if ( event.GetSetText() )
     {
         if ( event.GetText() != GetValue() )
             SetValue(event.GetText());
     }
 }
     if ( event.GetSetText() )
     {
         if ( event.GetText() != GetValue() )
             SetValue(event.GetText());
     }
 }

+#endif // !wxRICHTEXT_DERIVES_FROM_TEXTCTRLBASE

 
 // ----------------------------------------------------------------------------
 // hit testing
 
 // ----------------------------------------------------------------------------
 // hit testing


@@ -1623,14 +1625,20 @@ wxRichTextCtrl::HitTest(const wxPoint& pt,
     ((wxRichTextCtrl*)this)->PrepareDC(dc);
 
     int hit = ((wxRichTextCtrl*)this)->GetBuffer().HitTest(dc, pt, *pos);
     ((wxRichTextCtrl*)this)->PrepareDC(dc);
 
     int hit = ((wxRichTextCtrl*)this)->GetBuffer().HitTest(dc, pt, *pos);

-    if (hit == wxRICHTEXT_HITTEST_BEFORE)
-        return wxTE_HT_BEFORE;
-    else if (hit == wxRICHTEXT_HITTEST_AFTER)
-        return wxTE_HT_BEYOND;
-    else if (hit == wxRICHTEXT_HITTEST_ON)
-        return wxTE_HT_ON_TEXT;
-    else
-        return wxTE_HT_UNKNOWN;
+
+    switch ( hit )
+    {
+        case wxRICHTEXT_HITTEST_BEFORE:
+            return wxTE_HT_BEFORE;
+
+        case wxRICHTEXT_HITTEST_AFTER:
+            return wxTE_HT_BEYOND;
+
+        case wxRICHTEXT_HITTEST_ON:
+            return wxTE_HT_ON_TEXT;
+    }
+
+    return wxTE_HT_UNKNOWN;

 }
 
 // ----------------------------------------------------------------------------
 }
 
 // ----------------------------------------------------------------------------


@@ -1700,8 +1708,8 @@ bool wxRichTextCtrl::WriteImage(const wxImage& image, int bitmapType)
     wxImage image2 = image;
     if (imageBlock.MakeImageBlock(image2, bitmapType))
         return WriteImage(imageBlock);
     wxImage image2 = image;
     if (imageBlock.MakeImageBlock(image2, bitmapType))
         return WriteImage(imageBlock);

-    else
-        return false;
+
+    return false;

 }
 
 bool wxRichTextCtrl::WriteImage(const wxString& filename, int bitmapType)
 }
 
 bool wxRichTextCtrl::WriteImage(const wxString& filename, int bitmapType)


@@ -1711,8 +1719,8 @@ bool wxRichTextCtrl::WriteImage(const wxString& filename, int bitmapType)
     wxImage image;
     if (imageBlock.MakeImageBlock(filename, bitmapType, image, false))
         return WriteImage(imageBlock);
     wxImage image;
     if (imageBlock.MakeImageBlock(filename, bitmapType, image, false))
         return WriteImage(imageBlock);

-    else
-        return false;
+
+    return false;

 }
 
 bool wxRichTextCtrl::WriteImage(const wxRichTextImageBlock& imageBlock)
 }
 
 bool wxRichTextCtrl::WriteImage(const wxRichTextImageBlock& imageBlock)


@@ -1729,9 +1737,8 @@ bool wxRichTextCtrl::WriteImage(const wxBitmap& bitmap, int bitmapType)
         wxImage image = bitmap.ConvertToImage();
         if (image.Ok() && imageBlock.MakeImageBlock(image, bitmapType))
             return WriteImage(imageBlock);
         wxImage image = bitmap.ConvertToImage();
         if (image.Ok() && imageBlock.MakeImageBlock(image, bitmapType))
             return WriteImage(imageBlock);

-        else
-            return false;

     }
     }

+

     return false;
 }
 
     return false;
 }
 


@@ -1763,8 +1770,8 @@ void wxRichTextCtrl::Cut()
         GetBuffer().CopyToClipboard(range);
 
         DeleteSelectedContent();
         GetBuffer().CopyToClipboard(range);
 
         DeleteSelectedContent();

-        Layout();
-        Refresh();
+        LayoutContent();
+        Refresh(false);

     }
 }
 
     }
 }
 


@@ -1887,7 +1894,7 @@ void wxRichTextCtrl::DoSetSelection(long from, long to, bool WXUNUSED(scrollCare
 {
     m_selectionAnchor = from;
     m_selectionRange.SetRange(from, to);
 {
     m_selectionAnchor = from;
     m_selectionRange.SetRange(from, to);

-    Refresh();
+    Refresh(false);

     PositionCaret();
 }
 
     PositionCaret();
 }
 


@@ -1915,9 +1922,9 @@ void wxRichTextCtrl::Remove(long from, long to)
         from,                           // New caret position
         this);
 
         from,                           // New caret position
         this);
 

-    Layout();
+    LayoutContent();

     if (!IsFrozen())
     if (!IsFrozen())

-        Refresh();
+        Refresh(false);

 }
 
 bool wxRichTextCtrl::IsModified() const
 }
 
 bool wxRichTextCtrl::IsModified() const


@@ -2259,8 +2266,8 @@ bool wxRichTextCtrl::GetCaretPositionForIndex(long position, wxRect& rect)
         rect = wxRect(pt, wxSize(wxRICHTEXT_DEFAULT_CARET_WIDTH, height));
         return true;
     }
         rect = wxRect(pt, wxSize(wxRICHTEXT_DEFAULT_CARET_WIDTH, height));
         return true;
     }

-    else
-        return false;
+
+    return false;

 }
 
 /// Gets the line for the visible caret position. If the caret is
 }
 
 /// Gets the line for the visible caret position. If the caret is


@@ -2289,7 +2296,7 @@ wxRichTextLine* wxRichTextCtrl::GetVisibleLineForCaretPosition(long caretPositio
 bool wxRichTextCtrl::MoveCaret(long pos, bool showAtLineStart)
 {
     if (GetBuffer().GetDirty())
 bool wxRichTextCtrl::MoveCaret(long pos, bool showAtLineStart)
 {
     if (GetBuffer().GetDirty())

-        Layout();
+        LayoutContent();

 
     if (pos <= GetBuffer().GetRange().GetEnd())
     {
 
     if (pos <= GetBuffer().GetRange().GetEnd())
     {


@@ -2305,7 +2312,7 @@ bool wxRichTextCtrl::MoveCaret(long pos, bool showAtLineStart)
 
 /// Layout the buffer: which we must do before certain operations, such as
 /// setting the caret position.
 
 /// Layout the buffer: which we must do before certain operations, such as
 /// setting the caret position.

-bool wxRichTextCtrl::Layout(bool onlyVisibleRect)
+bool wxRichTextCtrl::LayoutContent(bool onlyVisibleRect)

 {
     if (GetBuffer().GetDirty() || onlyVisibleRect)
     {
 {
     if (GetBuffer().GetDirty() || onlyVisibleRect)
     {


@@ -2321,17 +2328,17 @@ bool wxRichTextCtrl::Layout(bool onlyVisibleRect)
             flags |= wxRICHTEXT_LAYOUT_SPECIFIED_RECT;
             availableSpace.SetPosition(GetLogicalPoint(wxPoint(0, 0)));
         }
             flags |= wxRICHTEXT_LAYOUT_SPECIFIED_RECT;
             availableSpace.SetPosition(GetLogicalPoint(wxPoint(0, 0)));
         }

-        
+

         wxClientDC dc(this);
         dc.SetFont(GetFont());
         wxClientDC dc(this);
         dc.SetFont(GetFont());

-        
+

         PrepareDC(dc);
         PrepareDC(dc);

-        
+

         GetBuffer().Defragment();
         GetBuffer().UpdateRanges();     // If items were deleted, ranges need recalculation
         GetBuffer().Layout(dc, availableSpace, flags);
         GetBuffer().SetDirty(false);
         GetBuffer().Defragment();
         GetBuffer().UpdateRanges();     // If items were deleted, ranges need recalculation
         GetBuffer().Layout(dc, availableSpace, flags);
         GetBuffer().SetDirty(false);

-        
+

         if (!IsFrozen())
             SetupScrollbars();
     }
         if (!IsFrozen())
             SetupScrollbars();
     }


@@ -2510,8 +2517,8 @@ bool wxRichTextCtrl::SetDefaultStyleToCursorStyle()
         SetDefaultStyle(attr);
         return true;
     }
         SetDefaultStyle(attr);
         return true;
     }

-    else
-        return false;
+
+    return false;

 }
 
 /// Returns the first visible position in the current view
 }
 
 /// Returns the first visible position in the current view