#include "wx/vscroll.h"
+#include "wx/utils.h" // For wxMin/wxMax().
+
// ============================================================================
// wxVarScrollHelperEvtHandler declaration
// ============================================================================
}
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 )
{
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;