How do I set an Icon background transparent in MFC?

Question

2.00/5 (1 vote)

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VS2010

Hi,

I tried to implement the default MFC-Icon in an Menu. Got it, but unfortunatly, the background of the icon is NOT transparent. why not and how can I set it to transparent?

my source code:

CMenu* mmenu = GetMenu();  
 
HICON hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
mmenu->SetMenuItemBitmaps(ID_TEST, MF_BYCOMMAND, ConvertIconToBitmap(hIcon), NULL);

the converting function:

C++

CBitmap* CTestDlg::ConvertIconToBitmap(HICON hIcon)
{
    CDC dc;
    CBitmap bmp;
    CClientDC ClientDC(this);
    dc.CreateCompatibleDC(&ClientDC);
    bmp.CreateCompatibleBitmap(&ClientDC, 16, 16);
    CBitmap* pOldBmp = (CBitmap*)dc.SelectObject(&bmp);
    ::DrawIconEx(dc.GetSafeHdc(), 0, 0, hIcon, 16, 16, 0, (HBRUSH)RGB(255, 255, 255), DI_NORMAL);
    dc.SelectObject(pOldBmp);
    dc.DeleteDC();
    HBITMAP hBitmap = (HBITMAP)::CopyImage((HANDLE)((HBITMAP)bmp), IMAGE_BITMAP, 0, 0, LR_DEFAULTSIZE);
 
    return CBitmap::FromHandle(hBitmap);
}

I tried to change the HBRUSH within the DrawIconEx, but the background changes only to black when RGB is (0,0,0). All other combinations paint the background white :(

Posted 8-Dec-14 19:19pm

Member 10730024

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Comments

Richard MacCutchan 9-Dec-14 4:55am

I think you need to set it in the icon editor.

Member 10730024 9-Dec-14 6:19am

I'm sorry I dont understand what u mean

Richard MacCutchan 9-Dec-14 6:25am

Try using the icon editor in Visual Studio to change the background.

Member 10730024 9-Dec-14 6:30am

I've load the default MFC-Icon which appears also in the guis headline. the background is demonstrably transparent, but for some reason the background of the same icon in the submenu is white...

Richard MacCutchan 9-Dec-14 6:43am

That is because of the white brush you are using to paint the background. I am not sure if it will help, but take a look at http://msdn.microsoft.com/en-us/library/dd162965(v=vs.85).aspx.

Member 10730024 9-Dec-14 7:27am

did not work...

Sergey Alexandrovich Kryukov 9-Dec-14 10:48am

If you think a bit, you will probably understand that the expression "transparent background" is the oxymoron.
Transparency is defined by what you can see through; but you did not explain it. Maybe, this is merely phrasing. Most likely, you mean that some pixels on the icon image should be transparent and some not, which is achieved by having, say ARGB or RGBA pixel type, with different A (alpha-channel representing opacity).
—SA

merano99 10-Dec-14 17:15pm

Does it help to set HBRUSH to 0, not RGB ?

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