X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/4719e58dc1797a219b7e90322e07cc81b5149bdc..b9efe021b554fa3967d1442cf758435c5cd5ae8f:/include/wx/vscroll.h

diff --git a/include/wx/vscroll.h b/include/wx/vscroll.h
index bdbb29f206..5ac9a142c0 100644
--- a/include/wx/vscroll.h
+++ b/include/wx/vscroll.h
@@ -95,10 +95,10 @@ public:
     virtual bool ScrollPages(int pages);
 
     // redraw the specified line
-    void RefreshLine(size_t line);
+    virtual void RefreshLine(size_t line);
 
     // redraw all lines in the specified range (inclusive)
-    void RefreshLines(size_t from, size_t to);
+    virtual void RefreshLines(size_t from, size_t to);
 
     // return the item at the specified (in physical coordinates) position or.
 
@@ -118,14 +118,26 @@ public:
     size_t GetLineCount() const { return m_lineMax; }
 
     // get the first currently visible line
-    size_t GetFirstVisibleLine() const { return m_lineFirst; }
+    size_t GetVisibleBegin() const { return m_lineFirst; }
 
-    // get the last currently visible line
-    size_t GetLastVisibleLine() const { return m_lineFirst + m_nVisible - 1; }
+    // get the first currently visible line
+    size_t GetVisibleEnd() const { return m_lineFirst + m_nVisible; }
 
     // is this line currently visible?
     bool IsVisible(size_t line) const
-        { return line >= m_lineFirst && line <= GetLastVisibleLine(); }
+        { return line >= GetVisibleBegin() && line < GetVisibleEnd(); }
+
+
+    // this is the same as GetVisibleBegin(), exists to match
+    // GetLastVisibleLine() and for backwards compatibility only
+    size_t GetFirstVisibleLine() const { return m_lineFirst; }
+
+    // get the last currently visible line
+    //
+    // this function is unsafe as it returns (size_t)-1 (i.e. a huge positive
+    // number) if the control is empty, use GetVisibleEnd() instead, this one
+    // is kept for backwards compatibility
+    size_t GetLastVisibleLine() const { return GetVisibleEnd() - 1; }
 
 
 protected: