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Introduction

This code helps you to load a bitmap from a resource or from a file and show it in a MDI View. It enables scrolling and also scrolls the bitmap accordingly.

Steps to follow

Follow the following seven easy steps :-

Step 1

Create a MDI Application by selecting Multiple Documents Interface in Step 1 of the app-wizard process.

Step 2

In the 6th step, select the View class and in the combo box called base class , select CScrollView and then click Finish.

Step 3

Create the following variables in the View class (yourview.h file)

• CDC m_MemDC;
• CBitmap m_bmpView;
• int m_nBmpWidth,m_nBmpHeight;

Step 4

In the View class , select the OnInitialUpdate function and change the code like this.

void CMDIView::OnInitialUpdate() 
{
    CDC *pDC = this->GetDC();

    m_MemDC.CreateCompatibleDC(pDC);

    m_bmpView.LoadBitmap(IDB_BMP_BKGND);    
    // Here IDB_BMP_BKGND is a bitmap included in the resource

    // Note : You can also load a bitmap from a file in the 

    // hard disk instead of using the bmp in the resource.


    m_MemDC.SelectObject(&m_bmpView);

    BITMAP Bitmap;
    m_bmpView.GetBitmap(&Bitmap);

    m_nBmpHeight = Bitmap.bmHeight;
    m_nBmpWidth = Bitmap.bmWidth;

    CSize size(m_nBmpWidth,m_nBmpHeight);
    SetScrollSizes(MM_TEXT,size);

    this->ReleaseDC(pDC);    
}

Step 5

Select the OnDraw function and change the code inside like this

void CMDIView::OnDraw(CDC* pDC)
{
    pDC->BitBlt(0,0,m_nBmpWidth,m_nBmpHeight,
        &m_MemDC,0,0,SRCCOPY);

    SetScrollSizes(MM_TEXT, CSize(m_nBmpWidth,m_nBmpHeight));
    CChildFrame *pParentFrame =
        (CChildFrame *)this->GetParentFrame();
    pParentFrame->RecalcLayout();
    ResizeParentToFit();    
}

Step 6

To prevent flickering of the bitmap when its being scrolled, override the View's OnEraseBkgnd and the ChildFrame's OnEraseBkgnd like this.

BOOL CMDIView::OnEraseBkgnd(CDC* pDC) 
{
    return TRUE;
}   

BOOL CChildFrame::OnEraseBkgnd(CDC* pDC) 
{
    return FALSE;
}

Step 7

Compile your project and run it. That's it. Now, you have a scrolling window which displays a bitmap too.  All luck and have a great time.

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ChildFrame????? Furries 3:28 25 Nov '04   I replaced this unknown type with CMainFrm and now it works. I neither had CChildFrm.h or cpp files nor did VC++ (6) know about ChildFrame. Still, it seems to be working. Anyone able to clear up this mystery for me? Sign In·View Thread·PermaLink Re: ChildFrame????? PeteOlcott 6:22 19 Aug '07   If you followed all of the steps correctly and are using MSVC++ 6.0, then the only missing steps are: (1) Include the following line of code in your View.cpp #include "ChildFrm.h" (2) Right Click ProjectName resources in resource view: (a) Insert (b) Select Bitmap, (c) Import (3) Right Click IDB_BITMAP1: Properties Change ID: to IDB_BMP_BKGND The program then worked as described. Sign In·View Thread·PermaLink 2.00/5 Thanks Ajay_Chopra 3:15 17 Jun '04   I wanted to implement similar stuff in Single Document Interface. I could easily implement it after going through your code. Thanks Sign In·View Thread·PermaLink Are these calls all needed CJN 22:50 8 Oct '03   Why are the following calls done in OnDraw()? SetScrollSizes(MM_TEXT, CSize((int)m_nBmpWidth, (int)m_nBmpHeight)); CChildFrame *pParentFrame = (CChildFrame *)this->GetParentFrame(); pParentFrame->RecalcLayout(); ResizeParentToFit(); Couldn't the SetScrollSizes() call be done only when the document size changes (i.e. only when a new image is loaded)? Couldn't the last 2 calls be done just when the window is resized e.g. in OnSize()? Regards, C Newell Sign In·View Thread·PermaLink How to load bitmap from disk file CJN 17:02 8 Oct '03   This is an interesting and succinct article. You mention "// Here IDB_BMP_BKGND is a bitmap included in the resource // Note : You can also load a bitmap from a file in the // hard disk instead of using the bmp in the resource." This seems to imply LoadBitmap(LPCTSTR) can take a disk filename as an argument, but that gave me an exception. What is the easiest way to load a bitmap from a disk file? Regards Colin Newell Sign In·View Thread·PermaLink 2.00/5 Re: How to load bitmap from disk file Anonymous 3:25 14 Oct '04   There is a function LoadImage( ) but it works only with "bmp". Can somebody tell me how to work with "jpeg". Sign In·View Thread·PermaLink Re: How to load bitmap from disk file shizulooi 0:01 14 Jul '09   Hi all.. I would like to use this function too..to load image from local drive but not from resource.. I'm using VC++ 6.0, under bitmap function, I didn't found LoadImage() function.. except using LoadImage(), got other function I can use it to load image from local drive..?? Please advise.. Thank you.. Shizu.. Sign In·View Thread·PermaLink Top of the class Andy Kuiper 3:05 30 May '03   Thanks a lot. That was exactly what I was searching for. It compiled with no probs after including "ChildFrm.h". Sign In·View Thread·PermaLink thanks Anonymous 20:36 3 Sep '02   thanks man Sign In·View Thread·PermaLink 3.25/5

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