- // current client window
- int noPagePositions = (int) ( (w/(double)m_xScrollPixelsPerLine) + 0.5 );
- if (noPagePositions < 1) noPagePositions = 1;
- if ( noPagePositions > m_xScrollLines )
- noPagePositions = m_xScrollLines;
-
- // Correct position if greater than extent of canvas minus
- // the visible portion of it or if below zero
- m_xScrollPosition = wxMin( m_xScrollLines - noPagePositions, m_xScrollPosition);
- m_xScrollPosition = wxMax( 0, m_xScrollPosition );
-
- m_win->SetScrollbar(wxHORIZONTAL, m_xScrollPosition, noPagePositions, m_xScrollLines);
- // The amount by which we scroll when paging
- SetScrollPageSize(wxHORIZONTAL, noPagePositions);
+ // current client window.
+ linesPerPage = w / m_xScrollPixelsPerLine;
+
+ // Special case. When client and virtual size are very close but
+ // the client is big enough, kill scrollbar.
+ if ((linesPerPage < m_xScrollLines) && (w >= wVirt)) ++linesPerPage;
+
+ if (linesPerPage >= m_xScrollLines)
+ {
+ // we're big enough to not need scrolling
+ linesPerPage =
+ m_xScrollLines =
+ m_xScrollPosition = 0;
+ }
+ else // we do need a scrollbar
+ {
+ if ( linesPerPage < 1 )
+ linesPerPage = 1;
+
+ // Correct position if greater than extent of canvas minus
+ // the visible portion of it or if below zero
+ const int posMax = m_xScrollLines - linesPerPage;
+ if ( m_xScrollPosition > posMax )
+ m_xScrollPosition = posMax;
+ else if ( m_xScrollPosition < 0 )
+ m_xScrollPosition = 0;
+ }