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Using 24bit Bitmap images with CListCtrl's Virtual List

Hi,

I was using a list control to show online data on it. The data comes very fast and i was showing Data as well as image of 24 bit. but it flickers the view since i was custom drawing for each data.

To minimize this flickering,  now i am using virtual list of list control for fast retreival of data. it has a tremendous improovment, but there is one problem, it does show the 24bit bitmap on it. it converts it into grey color.

can anybody help me to sort out this problem?

For more information i am using

CListCtrl::OnGetDispInfo(NMHDR* pNMHDR, LRESULT* pResult) [ for fill up the virtual list]
and
CListCtrl::SetItemCount(int nCount) [ for set the number of rows to display ]


Thanks in advance

devender
0
devendersys
Asked:
devendersys
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1 Solution
 
AmitAgarwalCommented:
Can you post your code?

Amit
0
 
devendersysAuthor Commented:
Here is the code

// VirtualListDlg.cpp : implementation file
//

#include "stdafx.h"
#include "VirtualList.h"
#include "VirtualListDlg.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CVirtualListDlg dialog

CVirtualListDlg::CVirtualListDlg(CWnd* pParent /*=NULL*/)
      : CDialog(CVirtualListDlg::IDD, pParent)
{
      //{{AFX_DATA_INIT(CVirtualListDlg)
            // NOTE: the ClassWizard will add member initialization here
      //}}AFX_DATA_INIT
      // Note that LoadIcon does not require a subsequent DestroyIcon in Win32
      m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}

void CVirtualListDlg::DoDataExchange(CDataExchange* pDX)
{
      CDialog::DoDataExchange(pDX);
      //{{AFX_DATA_MAP(CVirtualListDlg)
      DDX_Control(pDX, IDC_COMBO_STYLE, m_style);
      DDX_Control(pDX, IDC_LIST, m_list);
      //}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CVirtualListDlg, CDialog)
      //{{AFX_MSG_MAP(CVirtualListDlg)
      ON_WM_PAINT()
      ON_WM_QUERYDRAGICON()
      ON_BN_CLICKED(IDC_BUTTON_ADDTEN, OnButtonAddten)
      ON_BN_CLICKED(IDC_BUTTON_CLEAR, OnButtonClear)
      ON_NOTIFY(LVN_GETDISPINFO, IDC_LIST, OnGetdispinfoList)
      ON_NOTIFY(LVN_ODFINDITEM, IDC_LIST, OnOdfinditemList)
      ON_NOTIFY(LVN_ODCACHEHINT, IDC_LIST, OnOdcachehintList)
      ON_CBN_SELCHANGE(IDC_COMBO_STYLE, OnSelchangeComboStyle)
      ON_NOTIFY(NM_CLICK, IDC_LIST, OnClickList)
      ON_NOTIFY(LVN_KEYDOWN, IDC_LIST, OnKeydownList)
      //}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CVirtualListDlg message handlers

BOOL CVirtualListDlg::OnInitDialog()
{
      CDialog::OnInitDialog();

      // Set the icon for this dialog.  The framework does this automatically
      //  when the application's main window is not a dialog
      SetIcon(m_hIcon, TRUE);                  // Set big icon
      SetIcon(m_hIcon, FALSE);            // Set small icon

      ListView_SetExtendedListViewStyle(m_list.m_hWnd, LVS_EX_FULLROWSELECT|LVS_EX_CHECKBOXES );

      //Create image list
      m_imagelist.Create(IDB_BITMAP, 16, ILC_COLOR24, RGB(255, 255, 255));
      m_imagelistLarge.Create(IDB_BITMAP_LARGE, 32, ILC_COLOR4, RGB(255, 255, 255));
            
      m_list.SetImageList(&m_imagelist, LVSIL_SMALL);
      m_list.SetImageList(&m_imagelistLarge, LVSIL_NORMAL);
      
      m_list.InsertColumn(0, _T("Name"), LVCFMT_LEFT, 130);
      m_list.InsertColumn(1, _T("Address"), LVCFMT_LEFT, 200);

      m_style.SetCurSel(3);
      
      return TRUE;  // return TRUE  unless you set the focus to a control
}

// If you add a minimize button to your dialog, you will need the code below
//  to draw the icon.  For MFC applications using the document/view model,
//  this is automatically done for you by the framework.

void CVirtualListDlg::OnPaint()
{
      if (IsIconic())
      {
            CPaintDC dc(this); // device context for painting

            SendMessage(WM_ICONERASEBKGND, (WPARAM) dc.GetSafeHdc(), 0);

            // Center icon in client rectangle
            int cxIcon = GetSystemMetrics(SM_CXICON);
            int cyIcon = GetSystemMetrics(SM_CYICON);
            CRect rect;
            GetClientRect(&rect);
            int x = (rect.Width() - cxIcon + 1) / 2;
            int y = (rect.Height() - cyIcon + 1) / 2;

            // Draw the icon
            dc.DrawIcon(x, y, m_hIcon);
      }
      else
      {
            CDialog::OnPaint();
      }
}

// The system calls this to obtain the cursor to display while the user drags
//  the minimized window.
HCURSOR CVirtualListDlg::OnQueryDragIcon()
{
      return (HCURSOR) m_hIcon;
}

void CVirtualListDlg::OnButtonAddten()
{
      //Add 10 elements to the database
      for(int i=0; i<10; i++)
            m_database.push_back( CSampleData() );

      //Resize the list to add the elements to the list
      m_list.SetItemCount( m_database.size() );

      UpdateCount();
}

void CVirtualListDlg::OnButtonClear()
{
      //Clear database and list.
      m_database.clear();

      m_list.SetItemCount(0);

      UpdateCount();
}

void CVirtualListDlg::UpdateCount()
{
      CString temp;
      temp.Format(_T("%d items."), m_database.size());

      GetDlgItem(IDC_STATIC_COUNT)->SetWindowText(temp);
}


void CVirtualListDlg::OnSelchangeComboStyle()
{
      //Change list view style
      DWORD style = 0;

      switch( m_style.GetCurSel() )
      {
            case 0:
                  style = LVS_ICON;
                  break;
   
            case 1:
                  style = LVS_SMALLICON;
                  break;

            case 2:
                  style = LVS_LIST;
                  break;

            default:
                  style = LVS_REPORT;
                  break;
      }

      //Remove old style, and add new
      m_list.ModifyStyle(LVS_TYPEMASK, style);
      
      //Turn on/off check box
      if(style == LVS_ICON || style == LVS_SMALLICON)
            //Off
            ListView_SetExtendedListViewStyleEx(m_list.m_hWnd, LVS_EX_CHECKBOXES, 0);
      else
            //On
            ListView_SetExtendedListViewStyleEx(m_list.m_hWnd, LVS_EX_CHECKBOXES, LVS_EX_CHECKBOXES);
}

//This function is called when the list needs data. This is the most
//critical function when working with virtual lists.
void CVirtualListDlg::OnGetdispinfoList(NMHDR* pNMHDR, LRESULT* pResult)
{
      LV_DISPINFO* pDispInfo = (LV_DISPINFO*)pNMHDR;

      //Create a pointer to the item
      LV_ITEM* pItem= &(pDispInfo)->item;

      //Which item number?
      int itemid = pItem->iItem;

      //Do the list need text information?
      if (pItem->mask & LVIF_TEXT)
      {
            CString text;

            //Which column?
            if(pItem->iSubItem == 0)
            {
                  //Text is name
                  text = m_database[itemid].m_name;
            }
            else if (pItem->iSubItem == 1)
            {
                  //Text is slogan
                  text = m_database[itemid].m_slogan;
            }

            //Copy the text to the LV_ITEM structure
            //Maximum number of characters is in pItem->cchTextMax
            lstrcpyn(pItem->pszText, text, pItem->cchTextMax);
      }

      //Do the list need image information?
      if( pItem->mask & LVIF_IMAGE )
      {
            //Set which image to use
            pItem->iImage=m_database[itemid].m_image;
            
            //Show check box?
            if(IsCheckBoxesVisible())
            {
                  //To enable check box, we have to enable state mask...
                  pItem->mask |= LVIF_STATE;
                  pItem->stateMask = LVIS_STATEIMAGEMASK;

                  if(m_database[itemid].m_checked)
                  {
                        //Turn check box on..
                        pItem->state = INDEXTOSTATEIMAGEMASK(2);
                  }
                  else
                  {
                        //Turn check box off
                        pItem->state = INDEXTOSTATEIMAGEMASK(1);
                  }
            }
      }

      *pResult = 0;
}

//This functions is called when the user "writes" in the list box to find an item.
void CVirtualListDlg::OnOdfinditemList(NMHDR* pNMHDR, LRESULT* pResult)
{
      // pNMHDR has information about the item we should find
      // In pResult we should save which item that should be selected
      NMLVFINDITEM* pFindInfo = (NMLVFINDITEM*)pNMHDR;

      /* pFindInfo->iStart is from which item we should search.
         We search to bottom, and then restart at top and will stop
         at pFindInfo->iStart, unless we find an item that match
       */

      // Set the default return value to -1
      // That means we didn't find any match.
      *pResult = -1;

      //Is search NOT based on string?
      if( (pFindInfo->lvfi.flags & LVFI_STRING) == 0 )
      {
            //This will probably never happend...
            return;
      }

      /*
            Let's look on a sample list;
            
              Name
              Anders
            * Anna
              Annika
              Bob
              Emma
              Emmanuel

            Anna is selected.
            If "A" is written, Annika should be selected.
            If "AND" is written, Anders should be selected.
            If "ANNK" is written, the selection should stay on Anna.
            If "E" is written, Emma should be selected.

    */

      //This is the string we search for
      CString searchstr = pFindInfo->lvfi.psz;

//      TRACE(_T("Find: %s\n"), searchstr);
      
      int startPos = pFindInfo->iStart;
      //Is startPos outside the list (happens if last item is selected)
      if(startPos >= m_list.GetItemCount())
            startPos = 0;

      int currentPos=startPos;
      
      //Let's search...
      do
      {            
            //Do this word begins with all characters in searchstr?
            if( _tcsnicmp(m_database[currentPos].m_name, searchstr, searchstr.GetLength()) == 0)
            {
                  //Select this item and stop search.
                  *pResult = currentPos;
                  break;
            }

            //Go to next item
            currentPos++;

            //Need to restart at top?
            if(currentPos >= m_list.GetItemCount())
                  currentPos = 0;

      //Stop if back to start
      }while(currentPos != startPos);            
}

//This is called to give you a chance to catch data. Useless in most cases :-)
void CVirtualListDlg::OnOdcachehintList(NMHDR* pNMHDR, LRESULT* pResult)
{
      NMLVCACHEHINT* pCacheHint = (NMLVCACHEHINT*)pNMHDR;

/*      TRACE(      _T("Chache item %d to item %d\n"),
                  pCacheHint->iFrom,
                  pCacheHint->iTo );*/

      //... cache the data pCacheHint->iFrom to pCacheHint->iTo ...

      *pResult = 0;
}


void CVirtualListDlg::ToggleCheckBox(int item)
{
      //Change check box
      m_database[item].m_checked = !m_database[item].m_checked;

      //And redraw
      m_list.RedrawItems(item, item);
}

//This is called when user clicks on the list.
//If you had check box you have to write code to make them possible to toggle.
void CVirtualListDlg::OnClickList(NMHDR* pNMHDR, LRESULT* pResult)
{
      NMLISTVIEW* pNMListView = (NM_LISTVIEW*)pNMHDR;

      LVHITTESTINFO hitinfo;
      //Copy click point
      hitinfo.pt = pNMListView->ptAction;

      //Make the hit test...
      int item = m_list.HitTest(&hitinfo);

      if(item != -1)
      {
            //We hit one item... did we hit state image (check box)?
            //This test only works if we are in list or report mode.
            if( (hitinfo.flags & LVHT_ONITEMSTATEICON) != 0)
            {
                  ToggleCheckBox(item);
            }
      }

      
      *pResult = 0;
}

//This is called when a key i pressed down
void CVirtualListDlg::OnKeydownList(NMHDR* pNMHDR, LRESULT* pResult)
{
      LV_KEYDOWN* pLVKeyDown = (LV_KEYDOWN*)pNMHDR;

      //If user press space, toggle flag on selected item
      if( pLVKeyDown->wVKey == VK_SPACE )
      {
            //Check if check boxes are visible
            if( IsCheckBoxesVisible() )
            {
                  //Toggle if some item is selected
                  if(m_list.GetSelectionMark() != -1)
                        ToggleCheckBox( m_list.GetSelectionMark() );
            }
      }
      *pResult = 0;
}

BOOL CVirtualListDlg::IsCheckBoxesVisible()
{
      DWORD style = m_list.GetStyle();

      if( ((style & LVS_TYPEMASK) == LVS_LIST) ||
            ((style & LVS_TYPEMASK) == LVS_REPORT) )
                  return TRUE;

      return FALSE;
}
0
 
devendersysAuthor Commented:
Hi Amit,

Is there any luck?

Thanks
devender
0
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mahesh1402Commented:
Have you referred this how its implemented ..
http://www.codeproject.com/listctrl/virtuallist.asp

Your code seems to be same as above.. Tried to change above for 24 bit images ?

-MAHESH
0
 
devendersysAuthor Commented:
This code snippet is from the link above, but even it does not work for 24Bit Bitmaps. I am using this code for testing. you can check it for by changing the defult bitmap to 24bit Bitmap, and you can see the difference. the icon will be shown in grey scale.

devender
0
 
AmitAgarwalCommented:
Hi Devendar,

this was your code

//Create image list
m_imagelist.Create(IDB_BITMAP2, 640, ILC_COLOR4, RGB(255, 255, 255));


Why don't you use this code?

load the 24 bitmap in the CBitmap object
      m_bitmap.LoadBitmap(IDB_BITMAP2);
      m_imagelist.Create(640, 480, ILC_COLOR24,0, 4);
      m_imagelist.Add(&m_bitmap, RGB(255, 255, 255));

I tried and it worked

thanks
Amit
0
 
devendersysAuthor Commented:
its works great.

Thanks a lot amit.

Thanks
Devender
0

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