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bad return value for GetTextExtent

Posted on 2005-03-08
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Last Modified: 2013-11-20
Hi,

I can't get CDC::GetTextExtent to return correct values.
Here's my code:

        LOGFONT lf;  
        ZeroMemory(&lf, sizeof(LOGFONT));
        wcscpy(lf.lfFaceName, _T("Arial Black") );
        lf.lfHeight = 14;
      CFont font;
        font.CreateFontIndirect( &lf );
      context.SelectObject( font );
      CSize size = context.GetTextExtent( _T("Test") );

The value of size is not correct. It doesn't even depend on the value of the input string.

What's wrong ?
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Question by:__Julien__
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5 Comments
 
LVL 48

Accepted Solution

by:
AlexFM earned 150 total points
ID: 13487230
context.SelectObject( font );

Replace with:

context.SelectObject( &font );

Test values returned by CreateFontIndirect and SelectObject to see what is the problem.
0
 

Author Comment

by:__Julien__
ID: 13487333
That was indeed an error but I've still the same problem after correction.
0
 

Author Comment

by:__Julien__
ID: 13496318
I've tried the previous code in a new dialog box and it worked. So, I guess the problem lies in the device context. I created it like this (it's in an ActiveX control):

      HRESULT OnDraw(ATL_DRAWINFO& di)
      {
            CDC context;
            context.SetOutputDC( di.hdcDraw );
                ...

It worked well for drawing lines and rectangles but not for this. Why?
0
 

Author Comment

by:__Julien__
ID: 13496622
With Attach instead of SetOutputDC, it works fine.
0
 
LVL 55

Expert Comment

by:Jaime Olivares
ID: 13503974
try to use context.SetMapMode(MM_TEXT); before calling GetTextExtent().
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