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hello,

thanks for your previous reply, now i got another tiny troubles, my
CExtscrollbars doesn’t appears in my CExtScrollWnd. I set the virtual space using the method .OnSwSetScrollRange(SB_VERT ,0,mybitmap_width,true)
then .OnSwRecalcLayout(true);

but nothing show up. But if i do OnSwHasScrollBar(SB_HORZ) that return
me true. kinda weird
What’s the proper way to force the display of cextscrollbars within a
cextscrollwnd ?

here s a extract of my code:

BOOL CBankPanel::Create(LPCTSTR lpszClassName,
                            LPCTSTR lpszWindowName,
                            DWORD dwStyle,
                            const RECT& rect,
                            CWnd* pParentWnd,
                            UINT nID,
                            CCreateContext* pContext)
{
    BOOL ret;

    if(!CWnd::Create(    lpszClassName,
                        lpszWindowName,
                        dwStyle,
                        rect,
                        pParentWnd,
                        nID,
                        pContext))
    {
        ASSERT(FALSE);
        return FALSE;
    }

    // create the bars
    if(!m_HBar.Create(SBS_HORZ | SBS_TOPALIGN | WS_CHILD, CRect(5, 5, 100,
30),
this,10000))
    {
        ASSERT(FALSE);
        return FALSE;
    }
    m_HBar.m_bReflectParentSizing=true;

    if(!m_VBar.Create(SBS_VERT | SBS_LEFTALIGN | WS_CHILD, CRect(5, 5,
100,
30), this,10001))
    {
        ASSERT(FALSE);
        return FALSE;
    }
    m_VBar.m_bReflectParentSizing=true;

    return TRUE;
}

CBankPanel::~CBankPanel()
{
}

void CBankPanel::OnSwPaint(CDC & dc)
{
}

CScrollBar* CBankPanel::GetScrollBarCtrl(int nBar) const
{
    if(nBar==SB_HORZ)
        return (CScrollBar*) ( (m_HBar.GetSafeHwnd() != NULL) ?
(&m_HBar) :
NULL );
    else
        return (CScrollBar*) ( (m_VBar.GetSafeHwnd() != NULL) ?
(&m_VBar) :
NULL );
}

bool CBankPanel::OnSwDoScroll(UINT nScrollCode,UINT nPos,bool
bDoScroll)
{

    return true;
}

We decided to help you code your image viewer based on the CExtScrollWnd class. We called it CChildView and you may use it (instead of the child view) in your MDI/SDI application that is not based on the document/view architecture. To assign a bitmap to the image viewer window, the CChildView::LoadBitmap or CChildView::SetBitmap method can be used. Here is the contents of the header file:

 #if (!defined __CHILD_VIEW_H)
#define __CHILD_VIEW_H
 
#if _MSC_VER > 1000
 #pragma once
#endif
 
class CChildView : public CExtScrollWnd
{
public:
 CChildView();
public:
 bool Create(
  CWnd * pWndParent,
  UINT nDlgCtrlID = AFX_IDW_PANE_FIRST,
  DWORD dwWndStyle =
   WS_CHILD
    |WS_VISIBLE
    |WS_CLIPSIBLINGS
    |WS_CLIPCHILDREN,
  CRect rc = CRect(0,0,0,0)
  );
 static LPCTSTR RegisterChildViewWndClass();
 void SetBitmap(
  HBITMAP hBitmap
  );
 bool LoadBitmap(
  UINT nResourceID
  );
protected:
 CBitmap m_bmp;
 CSize m_sizeHelperBmp;
 CExtScrollBar
  m_wndScrollBarH,
  m_wndScrollBarV;
 // ClassWizard generated virtual function overrides
 //{{AFX_VIRTUAL(CChildView)
 public:
 virtual CScrollBar * GetScrollBarCtrl(int nBar) const;
 protected:
 virtual BOOL PreCreateWindow(CREATESTRUCT& cs);
 //}}AFX_VIRTUAL
public:
 virtual ~CChildView();
 virtual CSize OnSwGetTotalSize() const;
 virtual CSize OnSwGetPageSize(
  int nDirection
  ) const;
 virtual CSize OnSwGetLineSize(
  int nDirection
  ) const;
 virtual void OnSwPaint(
   CDC & dc
   );
 // Generated message map functions
protected:
 //{{AFX_MSG(CChildView)
 afx_msg int OnCreate(LPCREATESTRUCT lpCreateStruct);
 //}}AFX_MSG
 DECLARE_MESSAGE_MAP()
};
 
//{{AFX_INSERT_LOCATION}}
 
#endif (!defined __CHILD_VIEW_H) 

Here is its source file:

#include "stdafx.h"
#include "ChildView.h"
 
#ifdef _DEBUG
 #define new DEBUG_NEW
 #undef THIS_FILE
 static char THIS_FILE[] = __FILE__;
#endif
 
CChildView::CChildView()
 : m_sizeHelperBmp( 0, 0 )
{
}
 
CChildView::~CChildView()
{
 SetBitmap( NULL );
}
 
BEGIN_MESSAGE_MAP( CChildView, CExtScrollWnd )
 //{{AFX_MSG_MAP(CChildView)
 ON_WM_CREATE()
 //}}AFX_MSG_MAP
END_MESSAGE_MAP()
 
bool CChildView::Create(
 CWnd * pWndParent,
 UINT nDlgCtrlID, // = AFX_IDW_PANE_FIRST
 DWORD dwWndStyle, // =
  // WS_CHILD
  // |WS_VISIBLE
  // |WS_CLIPSIBLINGS
  // |WS_CLIPCHILDREN
 CRect rc // = CRect(0,0,0,0)
 )
{
 if( ! CWnd::Create(
   RegisterChildViewWndClass(),
   _T(""),
   dwWndStyle,
   rc,
   pWndParent,
   nDlgCtrlID
   )
  )
 {
  ASSERT( FALSE );
  return false;
 }
 return true;
}
 
LPCTSTR CChildView::RegisterChildViewWndClass()
{
 return
  ::AfxRegisterWndClass(
   CS_DBLCLKS
    |CS_HREDRAW
    |CS_VREDRAW,
   ::LoadCursor(
    NULL,
    IDC_ARROW
    )
   );
}
 
void CChildView::SetBitmap(
 HBITMAP hBitmap
 )
{
 if( ((HBITMAP)m_bmp.GetSafeHandle())
  == hBitmap )
   return;
 if( m_bmp.GetSafeHandle() != NULL )
  m_bmp.DeleteObject();
 m_sizeHelperBmp.cx
  = m_sizeHelperBmp.cy
  = 0;
 if( hBitmap != NULL )
 {
  m_bmp.Attach( hBitmap );
  BITMAP bmpInfo = { 0 };
  m_bmp.GetBitmap( &bmpInfo );
  m_sizeHelperBmp.cx =
   bmpInfo.bmWidth;
  m_sizeHelperBmp.cy =
   bmpInfo.bmHeight;
 } // if( hBitmap != NULL )
 OnSwUpdateScrollBars();
 OnSwDoRedraw();
}
 
bool CChildView::LoadBitmap(
 UINT nResourceID
 )
{
CBitmap bmp;
 if( ! bmp.LoadBitmap( nResourceID ) )
  return false;
 SetBitmap( (HBITMAP)bmp.Detach() );
 return true;
}
 
CSize CChildView::OnSwGetTotalSize() const
{
CSize sizeTotal( m_sizeHelperBmp );
 if( sizeTotal.cx == 0 )
  sizeTotal.cx = 1;
 if( sizeTotal.cy == 0 )
  sizeTotal.cy = 1;
 return sizeTotal;
}
 
CSize CChildView::OnSwGetPageSize(
 int nDirection
 ) const
{
 ASSERT_VALID( this );
 nDirection;
CRect rcClient = OnSwGetClientRect();
CSize sizePage = rcClient.Size();
CSize sizeTotal = m_sizeHelperBmp;
 if( sizePage.cx > sizeTotal.cx )
  sizePage.cx = 0;
 if( sizePage.cy > sizeTotal.cy )
  sizePage.cy = 0;
 return sizePage;
}
 
CSize CChildView::OnSwGetLineSize(
 int nDirection
 ) const
{
 ASSERT_VALID( this );
 nDirection;
 return CSize( 1, 1 );
}
 
void CChildView::OnSwPaint( CDC & dc )
{
 ASSERT_VALID( this );
 ASSERT( dc.GetSafeHdc() != NULL );
CRect rcClipBox;
 dc.GetClipBox( &rcClipBox );
COLORREF clrBk =
  g_PaintManager->GetColor(
   CExtPaintManager::CLR_3DFACE_OUT
   );
 dc.FillSolidRect(
  &rcClipBox,
  clrBk
  );
 if( m_bmp.GetSafeHandle() != NULL )
 {
  ASSERT(
    m_sizeHelperBmp.cx > 0
   && m_sizeHelperBmp.cy > 0
   );
  CDC dcSrc;
  if( dcSrc.CreateCompatibleDC(&dc) )
  {
   CBitmap * pOldSrc =
    dcSrc.SelectObject(&m_bmp);
   dc.BitBlt(
    0,
    0,
    m_sizeHelperBmp.cx,
    m_sizeHelperBmp.cy,
    &dcSrc,
    0,
    0,
    SRCCOPY
    );
   dcSrc.SelectObject(&pOldSrc);
  } // if( dcSrc.CreateCompatibleDC(&dc) )
 } // if( m_bmp.GetSafeHandle() != NULL )
CScrollBar * pScrollBarH =
  GetScrollBarCtrl( SB_HORZ );
CScrollBar * pScrollBarV =
  GetScrollBarCtrl( SB_VERT );
 if(  pScrollBarH != NULL
  && pScrollBarV != NULL
  && (pScrollBarH->GetStyle()&WS_VISIBLE) != 0
  && (pScrollBarV->GetStyle()&WS_VISIBLE) != 0
  )
 {
  CPoint ptVpRestore = dc.SetViewportOrg( 0, 0 );
  CRect rcSbH, rcSbV;
  pScrollBarH->GetWindowRect( &rcSbH );
  pScrollBarV->GetWindowRect( &rcSbV );
  CRect rcSbBoth(
   rcSbV.left,
   rcSbH.top,
   rcSbV.right,
   rcSbH.bottom
   );
  ScreenToClient( &rcSbBoth );
  dc.FillSolidRect(
   &rcSbBoth,
   clrBk
   );
  dc.SetViewportOrg( ptVpRestore );
 }
}
 
int CChildView::OnCreate(LPCREATESTRUCT lpCreateStruct) 
{
 if( CExtScrollWnd::OnCreate(lpCreateStruct) == -1 )
  return -1;
 if( ! m_wndScrollBarV.Create(
   WS_CHILD
    |WS_VISIBLE
    |SBS_VERT
    |SBS_RIGHTALIGN,
   CRect(0,0,0,0),
   this,
   1
   )
  )
 {
  ASSERT( FALSE );
  return -1;
 }
 if( ! m_wndScrollBarH.Create(
   WS_CHILD
    |WS_VISIBLE
    |SBS_HORZ
    |SBS_BOTTOMALIGN,
   CRect(0,0,0,0),
   this,
   2
   )
  )
 {
  ASSERT( FALSE );
  return -1;
 }
 m_wndScrollBarH.SyncReservedSpace(
  &m_wndScrollBarV
  );
 m_wndScrollBarV.SyncReservedSpace(
  &m_wndScrollBarH
  );
 return 0;
}
 
CScrollBar * CChildView::GetScrollBarCtrl(int nBar) const
{
 ASSERT_VALID( this );
 if( m_hWnd == NULL || (! ::IsWindow(m_hWnd) ) )
  return NULL;
 ASSERT( nBar == SB_HORZ || nBar == SB_VERT );
 if( nBar == SB_HORZ )
 {
  if( m_wndScrollBarH.GetSafeHwnd() != NULL )
   return
    ( const_cast
     < CExtScrollBar * >
     ( &m_wndScrollBarH ) );
 } // if( nBar == SB_HORZ )
 else
 {
  if( m_wndScrollBarV.GetSafeHwnd() != NULL )
   return
    ( const_cast
     < CExtScrollBar * >
     ( &m_wndScrollBarV )
     );
 } // else from if( nBar == SB_HORZ )
 return NULL;
}
 
BOOL CChildView::PreCreateWindow(CREATESTRUCT& cs) 
{
 if( ! CExtScrollWnd::PreCreateWindow(cs) )
 {
  ASSERT( FALSE );
  return FALSE;
 }
 cs.lpszClass = RegisterChildViewWndClass();
 return TRUE;
}

Here is how the OnCreate() method of the main frame window may look like ( CMainFrame::m_wndView is a window of the CChildView class:

 
int CMainFrame::OnCreate(LPCREATESTRUCT lpCreateStruct) 
{
 if( CFrameWnd::OnCreate(lpCreateStruct) == -1 )
  return -1;
 SetIcon(
  (HICON)::LoadImage(
   ::AfxGetInstanceHandle(),
   MAKEINTRESOURCE(IDR_MAINFRAME),
   IMAGE_ICON,
   16,
   16,
   0
   ),
  FALSE
  );
 SetIcon(
  (HICON)::LoadImage(
   ::AfxGetInstanceHandle(),
   MAKEINTRESOURCE(IDR_MAINFRAME),
   IMAGE_ICON,
   32,
   32,
   0
   ),
  TRUE
  );
 if( ! m_wndView.Create( this ) )
 {
  ASSERT( FALSE );
  return -1;
 }
 VERIFY(
  m_wndView.LoadBitmap(
   IDB_BITMAP_TEST
   )
  );
 return 0;
}

Please note that the CChildView code above uses CExtScrollBar-based scroll bar controls. But you may safely comment the lines that create the CChildView::m_wndScrollBarH and CChildView::m_wndScrollBarV windows in the CExtScrollWnd::OnCreate method so that you can see how the CChildView class works with built-in scroll bar areas in the non-client area of the window. But, of course, you can use ordinary scroll bar controls instead of built-in scroll bar-like areas if you don’t need to inject some additional controls next to the scroll bar window as it is done in, for example, MS Word.