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10 Dec 2001 165.6K   3.4K   70   31
Very primitive function that creates region from *.bmp files


This very simple function creates a region from a bitmap (.bmp) file. 8, 16, 24 and 32 bit color modes are supported.

The function takes two parameters:

  • hBmp - a handle to the bitmap image
  • color - transparent color
HRGN CreateRgnFromFile( HBITMAP hBmp, COLORREF color );

Using the function is very simple. For example, if you wish to set the window shape of your dialog, then in your OnInitDialog handler, do this:

BOOL CFileRgnDlg::OnInitDialog()

    // load image
    HBITMAP hBmp = (HBITMAP)LoadImage( AfxGetInstanceHandle(), 
                     "Rgn.bmp", IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE );
    // if fail - nothing to do
    if ( hBmp == NULL ) return TRUE;
    // create region, let the RED color be transparent

    HRGN hRgn = CreateRgnFromFile( hBmp, RGB(255,0,0) );

    // build memory dc for background
    CDC* dc = GetDC();
    m_dcBkGrnd = CreateCompatibleDC( dc->m_hDC );
    ReleaseDC( dc );
    // select background image
    SelectObject( m_dcBkGrnd, hBmp );
    // set window size the same as image size
    SetWindowPos( NULL, 0, 0, m_dwWidth, m_dwHeight, 
                           SWP_NOZORDER | SWP_NOMOVE );
    // assign region to window
    SetWindowRgn( hRgn, FALSE );

    return TRUE;


  • December 08, 2001
    • Cut & paste bug for 16-bit mode (white color as transparent did not work)
    • Pixels in a last column has not been used
    • Now you can use non-aligned (by width) images
  • June 11, 2001
    • ExtCreateRegion NT-problem (personal thanks to Martin for reporting it)


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Comments and Discussions

GeneralNot working on Windows Seven Pin
Dom306-May-11 21:19
Dom306-May-11 21:19 
GeneralRe: Not working on Windows Seven Pin
yzaz26-May-11 10:01
yzaz26-May-11 10:01 
GeneralMy vote of 5 Pin
ryan20fun9-Feb-11 20:15
ryan20fun9-Feb-11 20:15 
GeneralRotated Edit Box Pin
zakir1232-Sep-04 3:57
zakir1232-Sep-04 3:57 
GeneralCreateRgnFromFile question Pin
ralne31-Jul-04 10:23
ralne31-Jul-04 10:23 
GeneralRe: CreateRgnFromFile question Pin
yzaz5-Oct-04 13:59
yzaz5-Oct-04 13:59 
GeneralCustom controls ... Pin
kla_boot10-Jun-04 0:58
kla_boot10-Jun-04 0:58 
GeneralFantastic !!! Pin
Judge Gazza28-Apr-04 16:37
Judge Gazza28-Apr-04 16:37 
GeneralGreat example Pin
Chris Eatough10-Jun-03 0:42
Chris Eatough10-Jun-03 0:42 
GeneralAdapting this Pin
Kyudos11-Dec-02 3:27
Kyudos11-Dec-02 3:27 
Generalfinally found it Pin
Kevin Smith1-Nov-02 9:10
Kevin Smith1-Nov-02 9:10 
GeneralLarge Fonts Pin
Matt Philmon5-Feb-02 11:11
Matt Philmon5-Feb-02 11:11 
GeneralRegionToBitmap class... Pin
saturn5-Feb-02 1:53
saturn5-Feb-02 1:53 
GeneralArticle screwed up... no links Pin
Matt Philmon11-Dec-01 4:44
Matt Philmon11-Dec-01 4:44 
GeneralRe: Article screwed up... no links Pin
Chris Maunder11-Dec-01 10:44
cofounderChris Maunder11-Dec-01 10:44 
Generaldoesn't work in 16bits, look at this valid code ... Pin
20-Sep-01 0:28
suss20-Sep-01 0:28 
Generaldoesn't work when you want white as transparent color Pin
29-Aug-01 3:47
suss29-Aug-01 3:47 
GeneralI found here how to load HBITMAP from file... Pin
26-Aug-01 12:42
suss26-Aug-01 12:42 
Questionit's not working .... why? Pin
30-Jul-01 20:15
suss30-Jul-01 20:15 
QuestionWhat it taje to get ::ExtCreateRegion work in NT Pin
discoboyq9-Oct-00 17:01
discoboyq9-Oct-00 17:01 
AnswerRe: What it taje to get ::ExtCreateRegion work in NT Pin
1-Mar-01 23:04
suss1-Mar-01 23:04 
GeneralRe: What it taje to get ::ExtCreateRegion work in NT Pin
2-Apr-01 18:46
suss2-Apr-01 18:46 
Generalbuggy, slow code Pin
Feng Yuan www,fengyuan.com8-Sep-00 19:37
sussFeng Yuan www,fengyuan.com8-Sep-00 19:37 
GeneralRe: buggy, slow code Pin
Lance Gordon29-Sep-00 4:04
Lance Gordon29-Sep-00 4:04 
GeneralI need some help here... (rookie!) Pin
matux19-Jul-00 17:27
matux19-Jul-00 17:27 

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