void CSampleDialogScrollHelper::OnVScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)
{
if (0 == m_pWnd)
return;
const int line_offset = 60;
int delta_pos = 0;
switch (nSBCode)
{
case SB_LINEUP:
delta_pos = -line_offset;
break;
case SB_LINEDOWN:
delta_pos = line_offset;
break;
case SB_PAGEUP:
delta_pos = -m_page_size.cy;
break;
case SB_PAGEDOWN:
delta_pos = m_page_size.cy;
break;
case SB_THUMBTRACK:
delta_pos = Get32BitScrollPos(SB_VERT, pScrollBar) - m_scroll_pos.cy;
break;
case SB_THUMBPOSITION:
delta_pos = Get32BitScrollPos(SB_VERT, pScrollBar) - m_scroll_pos.cy;
break;
default:
return;
}
int new_scroll_pos = m_scroll_pos.cy + delta_pos;
if (new_scroll_pos < 0)
delta_pos = -m_scroll_pos.cy;
int max_scroll_pos = m_display_size.cy - m_page_size.cy;
if (new_scroll_pos > max_scroll_pos)
delta_pos = max_scroll_pos - m_scroll_pos.cy;
if (delta_pos != 0)
{
m_scroll_pos.cy += delta_pos;
m_pWnd->SetScrollPos(SB_VERT, m_scroll_pos.cy, TRUE);
m_pWnd->ScrollWindow(0, -delta_pos);
}
}
void CScrollHelper::OnVScroll(UINT nSBCode, UINT /*nPos*/, CScrollBar* pScrollBar)
{
if (m_attachWnd == nullptr)
return;
const int lineOffset = 60;
// Compute the desired change or delta in scroll position.
int deltaPos = 0;
switch (nSBCode) {
case SB_LINEUP:
// Up arrow button on scrollbar was pressed.
deltaPos = -lineOffset;
break;
case SB_LINEDOWN:
// Down arrow button on scrollbar was pressed.
deltaPos = lineOffset;
break;
case SB_PAGEUP:
// User clicked inbetween up arrow and thumb.
deltaPos = -m_pageSize.cy;
break;
case SB_PAGEDOWN:
// User clicked inbetween thumb and down arrow.
deltaPos = m_pageSize.cy;
break;
case SB_THUMBTRACK:
// Scrollbar thumb is being dragged.
deltaPos = Get32BitScrollPos(SB_VERT, pScrollBar) - m_scrollPos.cy;
break;
case SB_THUMBPOSITION:
// Scrollbar thumb was released.
deltaPos = Get32BitScrollPos(SB_VERT, pScrollBar) - m_scrollPos.cy;
break;
default:
// We don't process other scrollbar messages.
return;
}
// Compute the new scroll position.
int newScrollPos = m_scrollPos.cy + deltaPos;
// If the new scroll position is negative, we adjust
// deltaPos in order to scroll the window back to origin.
if (newScrollPos < 0)
deltaPos = -m_scrollPos.cy;
// If the new scroll position is greater than the max scroll position,
// we adjust deltaPos in order to scroll the window precisely to the
// maximum position.
int maxScrollPos = m_displaySize.cy - m_pageSize.cy;
if (newScrollPos > maxScrollPos)
deltaPos = maxScrollPos - m_scrollPos.cy;
// Scroll the window if needed.
if (deltaPos != 0) {
m_scrollPos.cy += deltaPos;
m_attachWnd->SetScrollPos(SB_VERT, m_scrollPos.cy, TRUE);
m_attachWnd->ScrollWindow(0, -deltaPos);
}
}
void CScrollHelper::OnHScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)
{
if ( m_attachWnd == NULL )
return;
const int lineOffset = 60;
// Compute the desired change or delta in scroll position.
int deltaPos = 0;
switch( nSBCode )
{
case SB_LINELEFT:
// Left scroll arrow was pressed.
deltaPos = -lineOffset;
break;
case SB_LINERIGHT:
// Right scroll arrow was pressed.
deltaPos = lineOffset;
break;
case SB_PAGELEFT:
// User clicked inbetween left arrow and thumb.
deltaPos = -m_pageSize.cx;
break;
case SB_PAGERIGHT:
// User clicked inbetween thumb and right arrow.
deltaPos = m_pageSize.cx;
break;
case SB_THUMBTRACK:
// Scrollbar thumb is being dragged.
deltaPos = Get32BitScrollPos(SB_HORZ, pScrollBar) - m_scrollPos.cx;
break;
case SB_THUMBPOSITION:
// Scrollbar thumb was released.
deltaPos = Get32BitScrollPos(SB_HORZ, pScrollBar) - m_scrollPos.cx;
break;
default:
// We don't process other scrollbar messages.
return;
}
// Compute the new scroll position.
int newScrollPos = m_scrollPos.cx + deltaPos;
// If the new scroll position is negative, we adjust
// deltaPos in order to scroll the window back to origin.
if ( newScrollPos < 0 )
deltaPos = -m_scrollPos.cx;
// If the new scroll position is greater than the max scroll position,
// we adjust deltaPos in order to scroll the window precisely to the
// maximum position.
int maxScrollPos = m_displaySize.cx - m_pageSize.cx;
if ( newScrollPos > maxScrollPos )
deltaPos = maxScrollPos - m_scrollPos.cx;
// Scroll the window if needed.
if ( deltaPos != 0 )
{
m_scrollPos.cx += deltaPos;
m_attachWnd->SetScrollPos(SB_HORZ, m_scrollPos.cx, TRUE);
DoTheScroll(-deltaPos, 0);
}
}
