C / C++ / MFC

CFont *pOldFont, newfont;<br />
TEXTMETRIC Metrics;<br />
LOGFONT lf;<br />
memset(&lf, 0, sizeof(LOGFONT));<br />
strcpy(lf.lfFaceName, "Arial");<br />
lf.lfHeight = - (long)FontSizeInPixels; // set the height - this is just a first try<br />
// FontSizeInPixels (a double) is the required height (say 10 mm) converted in pixels;<br />
// the height must be specified in logical units, which are pixels because the<br />
// the current mapMode is MM_TEXT. Note also the minus sign, this is normal (see doc. for LOGFONT)<br />
<br />
...  // set others font properties<br />
newfont.CreateFontIndirect(&lf);<br />
pOldFont = pDC->SelectObject(&newfont);<br />
pDC->GetTextMetrics(&Metrics); // get metrics (in pixels) for the font just created<br />
<br />
// here is the trick : the height of the ascent part is of course smaller than the required height;<br />
//so i correct the total height (lf.lfHeight) so that the ascent part grows up to the required height : <br />
<br />
lf.lfHeight = -(long) FontSizeInPixels * (FontSizeInPixels / (Metrics.tmAscent - Metrics.tmInternalLeading));<br />
<br />
// note that the real ascent height is (Metrics.tmAscent - Metrics.tmInternalLeading)<br />
// (this is not explicitly said in the doc. about TEXTMETRIC, but this is what i concluded by looking at the values in TEXTMETRIC)<br />
<br />
// example : let's say that FontSizeInPixels is 100 pixels and that GetTextMetrics <br />
// returned (Metrics.tmAscent - Metrics.tmInternalLeading) = 60;<br />
// so the new lf.lfHeight is 100 * 100/60 = 166<br />
<br />
newfont.Detach();<br />
newfont.DeleteObject();<br />
newfont.CreateFontIndirect(&lf); // recreate the font with the corrected height<br />
pDC->SelectObject(&newfont);<br />
// the following lines just check that the new height of the ascent part is very near of the required height :<br />
pDC->GetTextMetrics(&Metrics);<br />
ASSERT(fabs(Metrics.tmAscent - Metrics.tmInternalLeading - FontSizeInPixels) < 2);<br />

// In A.h

class A
{
public:
// Attributes
	static const int m_iMaxClmTextSize;
};

// In A.cpp
const int CClmListCtrl::m_iMaxClmTextSize = 10000;


// In B.cpp                                                      
#include "A.h"

void B::MyFunc()
{
    int MyArr[CClmListCtrl::m_iMaxClmTextSize];  // Won't compile
}