X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/d62b93c4677b5cf595f06bfae41e7ac38f2581b6..1d54b9d29706dbb43de5624bdf4a2aaa74b2350b:/include/wx/vscroll.h

diff --git a/include/wx/vscroll.h b/include/wx/vscroll.h
index cc500db1a9..5ac9a142c0 100644
--- a/include/wx/vscroll.h
+++ b/include/wx/vscroll.h
@@ -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: