Scrollbars don't work with many large columns

Just to give you potential idea - in some places bitmap used and function to allocate bitmap:

CBitmap bmpCache;

VERIFY(bmpCache.CreateCompatibleBitmap(pDC, W, H));

this function works only with W and H < 64K

 

So do your math with your so practical model with billions of columns

 

Right - sure - recent code only considered practical values - like few total witdh. Need to adjust for such extrema cases

Yes, I know that's an extreme case, but we have it.

We have two big lists with many columns inserted in one big report control for a kind of comparator.

In order to help you to enhance your report control more quickly, here is the kind of code needed :




// Return the maximum range of windows scroll bars
int GetScrollbarsRangeMax()
{
     return 30000;
}




// Set scroll bar data information, do not substract iPageSize from iPosMax
// pWnd = Window owning the scrollbars
BOOL SetScrollbarDataInfo(CWnd* pWnd, BOOL bHorizontalScrollbar, BOOL bForceShowDisabled, int iPos, int iPosMax, int iPageSize)
{
     HWND hwnd = pWnd->GetSafeHwnd();
     if ( !::IsWindow( hwnd ) )
          return FALSE;

     // Update scroll bars
     SCROLLINFO info;
     int iScrollbarsRangeMax = gGUI.GetScrollbarsRangeMax();

     if ( bForceShowDisabled )
     {
          ::memset( &info, 0, sizeof( info ) );
          info.cbSize = sizeof( info );

          info.fMask = SIF_RANGE | SIF_PAGE | SIF_POS;
          info.nMin = 0;
          info.nMax = 2;
          info.nPage = 5;
          info.nPos = 0;
          if ( bHorizontalScrollbar )
          {
               ::ShowScrollBar( hwnd, SB_HORZ, TRUE );
               ::SetScrollInfo( hwnd, SB_HORZ, &info, TRUE );
               ::EnableScrollBar( hwnd, SB_HORZ, ESB_DISABLE_BOTH );
          }
          else
          {
               ::ShowScrollBar( hwnd, SB_VERT, TRUE );
               ::SetScrollInfo( hwnd, SB_VERT, &info, TRUE );
               ::EnableScrollBar( hwnd, SB_VERT, ESB_DISABLE_BOTH );
          }
     }
     else
     {
          if ( iPosMax <= iPageSize )
          {
               // Hide the scroll bar
               if ( bHorizontalScrollbar )
                    ::ShowScrollBar( hwnd, SB_HORZ, FALSE );
               else
                    ::ShowScrollBar( hwnd, SB_VERT, FALSE );
          }
          else
          {
               // Show the scroll bar
               if ( bHorizontalScrollbar )
                    ::ShowScrollBar( hwnd, SB_HORZ, TRUE );
               else
                    ::ShowScrollBar( hwnd, SB_VERT, TRUE );

               if ( iPosMax >= iScrollbarsRangeMax )
               {
                    // Process the scroll bar differently if the total display height is too big
                    if ( bHorizontalScrollbar )
                         ::EnableScrollBar( hwnd, SB_HORZ, ESB_ENABLE_BOTH );
                    else
                         ::EnableScrollBar( hwnd, SB_VERT, ESB_ENABLE_BOTH );

                    ::memset( &info, 0, sizeof( info ) );
                    info.cbSize = sizeof( info );

                    info.fMask = SIF_RANGE | SIF_PAGE | SIF_POS;
                    info.nMin = 0;
                    info.nMax = iScrollbarsRangeMax;
                    info.nPage = 1;
                    info.nPos = iScrollbarsRangeMax * iPos / ( iPosMax - iPageSize );
                    if ( bHorizontalScrollbar )
                         ::SetScrollInfo( hwnd, SB_HORZ, &info, TRUE );
                    else
                         ::SetScrollInfo( hwnd, SB_VERT, &info, TRUE );
               }
               else
               {
                    // Process the scroll bar normally
                    ::memset( &info, 0, sizeof( info ) );
                    info.cbSize = sizeof( info );

                    info.fMask = SIF_RANGE | SIF_PAGE | SIF_POS;
                    info.nMin = 0;
                    info.nMax = iPosMax;
                    info.nPage = iPageSize;
                    info.nPos = iPos;

                    if ( bHorizontalScrollbar )
                         ::EnableScrollBar( hwnd, SB_HORZ, ESB_ENABLE_BOTH );
                    else
                         ::EnableScrollBar( hwnd, SB_VERT, ESB_ENABLE_BOTH );

                    if ( bHorizontalScrollbar )
                         ::SetScrollInfo( hwnd, SB_HORZ, &info, TRUE );
                    else
                         ::SetScrollInfo( hwnd, SB_VERT, &info, TRUE );
               }
          }
     }

     return TRUE;
}




// Process OnHScroll(...) & OnVScroll(...) and return the new scroll bar position
//
// Example :
//
//void CWndName::OnHScroll(UINT nSBCode, UINT nPos, //CScrollBar* pScrollBar)
//{
//     CRect r;
//     GetClientRect( &r );
//
//     SetViewOffsetXY(
//          ProcessOnVHScroll( nSBCode, nPos, m_iDisplayPosX, m_iMinimumDisplaySizeX, r.Width(), m_iScrollbarsStepSize ),
//          m_iDisplayPosY );
//
//     CWnd::OnHScroll(nSBCode, nPos, pScrollBar);
//}
//
//void CWndName::OnVScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)
//{
//     CRect r;
//     GetClientRect( &r );
//
//     SetViewOffsetXY(
//          m_iDisplayPosX,
//          ProcessOnVHScroll( nSBCode, nPos, m_iDisplayPosY, m_iMinimumDisplaySizeY, r.Height(), m_iScrollbarsStepSize ) );
//
//     CWnd::OnHScroll(nSBCode, nPos, pScrollBar);
//}
//
int ProcessOnVHScroll(UINT nSBCode, UINT nPos, int iPos, int iPosMax, int iPageSize, int iStepsSize)
{
     int iMaxPos = iPosMax - iPageSize;
     int iCurPos = iPos;
     int iScrollbarsRangeMax = gGUI.GetScrollbarsRangeMax();

     if ( iPosMax > iScrollbarsRangeMax )
     {
          iMaxPos = iScrollbarsRangeMax;
     }

     // Determine the new position of scroll box
     switch( nSBCode )
     {
          case SB_TOP: // Scroll to far top
               iCurPos = 0;
               break;

          case SB_BOTTOM: // Scroll to far bottom
               iCurPos = iMaxPos;
               break;

          case SB_ENDSCROLL: // End scroll
               break;

          case SB_LINEUP: // Scroll up
               iCurPos -= iStepsSize;
               break;

          case SB_LINEDOWN: // Scroll down
               iCurPos += iStepsSize;
               break;

          case SB_PAGEUP: // Scroll one page up
               iCurPos -= iPageSize;
               break;

          case SB_PAGEDOWN: // Scroll one page down
               iCurPos += iPageSize;
               break;

          case SB_THUMBPOSITION: // Scroll to absolute position. nPos is the position of the scroll box at the end of the drag operation
               if ( iPosMax > iScrollbarsRangeMax )
                    iCurPos = nPos * ( iPosMax - iPageSize ) / iScrollbarsRangeMax;
               else
                    iCurPos = nPos;
               break;

          case SB_THUMBTRACK: // Drag scroll box to specified position. nPos is the position that the scroll box has been dragged to
               if ( iPosMax > iScrollbarsRangeMax )
                    iCurPos = nPos * ( iPosMax - iPageSize ) / iScrollbarsRangeMax;
               else
                    iCurPos = nPos;
               break;
     }

     iCurPos = min( iCurPos, iPosMax - iPageSize );

     return iCurPos;
}

      
Regards,

I took a look at your code and you should not use value "nPos" of the OnHScroll(...)/OnVScroll(...). This value is limited to 16 bits due to the Windows message.

In the OnHScroll(...) & OnVScroll(...) methods, I think you just have to retrieve this value using the GetScrollInfo(...) which will give you a 32 bits value.

We don't make this change because we don't want to have any conflicts with your future changes.

Regards,

Ok, we will do your job and fix your OnHScroll(...) & OnVScroll(...).

Regards,

In some moment you was interested in Expand-Collapse action with all deep levels covered - I propose you to test current app but you did not try?

it was 2 different threads - http://forum.codejock.com/forum_posts.asp?TID=13387 (about multi-selection) and it was another thread about the problem with expand all function which not covered full deep of hierarchy but I can't find it now?

I never posted the ExpandAll() query.

It was someone else : https://forum.codejock.com/forum_posts.asp?TID=13445&KW=expandall

I found the clue by myself.