X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/4c51a665c649f7579fb39e62070cef4f66b3210d..bf2c43c76e2819be443ab1d830ab68d9569d66b1:/src/generic/vscroll.cpp

diff --git a/src/generic/vscroll.cpp b/src/generic/vscroll.cpp
index c1b5a4071a..3a66aa34b5 100644
--- a/src/generic/vscroll.cpp
+++ b/src/generic/vscroll.cpp
@@ -4,7 +4,6 @@
 // Author:      Vadim Zeitlin
 // Modified by: Brad Anderson, David Warkentin
 // Created:     30.05.03
-// RCS-ID:      $Id$
 // Copyright:   (c) 2003 Vadim Zeitlin <vadim@wxwindows.org>
 // Licence:     wxWindows licence
 /////////////////////////////////////////////////////////////////////////////
@@ -31,6 +30,8 @@
 
 #include "wx/vscroll.h"
 
+#include "wx/utils.h"   // For wxMin/wxMax().
+
 // ============================================================================
 // wxVarScrollHelperEvtHandler declaration
 // ============================================================================
@@ -308,14 +309,17 @@ size_t wxVarScrollHelperBase::GetNewScrollPosition(wxScrollWinEvent& event) cons
     }
     else if ( evtType == wxEVT_SCROLLWIN_PAGEUP )
     {
-        return FindFirstVisibleFromLast(m_unitFirst);
+        // Page up should do at least as much as line up.
+        return wxMin(FindFirstVisibleFromLast(m_unitFirst),
+                    m_unitFirst ? m_unitFirst - 1 : 0);
     }
     else if ( evtType == wxEVT_SCROLLWIN_PAGEDOWN )
     {
+        // And page down should do at least as much as line down.
         if ( GetVisibleEnd() )
-            return GetVisibleEnd() - 1;
+            return wxMax(GetVisibleEnd() - 1, m_unitFirst + 1);
         else
-            return GetVisibleEnd();
+            return wxMax(GetVisibleEnd(), m_unitFirst + 1);
     }
     else if ( evtType == wxEVT_SCROLLWIN_THUMBRELEASE )
     {
@@ -482,10 +486,10 @@ void wxVarScrollHelperBase::RefreshUnits(size_t from, size_t to)
         to = GetVisibleEnd();
 
     // calculate the rect occupied by these units on screen
-    int orient_size, nonorient_size, orient_pos;
-    orient_size = nonorient_size = orient_pos = 0;
+    int orient_size = 0,
+        orient_pos = 0;
 
-    nonorient_size = GetNonOrientationTargetSize();
+    int nonorient_size = GetNonOrientationTargetSize();
 
     for ( size_t nBefore = GetVisibleBegin();
           nBefore < from;