我在读书Programming.Windows.5th.Edition,CharlesPetzold当我在做图4-5的时候。SYSMETS1.C，遇到如下代码:cxCaps=(tm.tmPitchAndFamily&1?3:2)*cxChar/2;书上有解释，SYSMETS1alsosavesanaveragewidthofuppercaselettersinthestaticvariablecxCaps.Forafixed-pitchfont,cxCapswouldequalcxChar.Foravariable-widthfont,cxCapsissetto150percentof

如果我运行下面的代码，我会得到以下带有“cambriaMath”字体的tm和gm结构的值:tm.tmHeight=161tm.tmAscent=90tm.tmDescent=71和gm.gmBlackBoxY=14tm中的值显然有误!gmBlackBoxY似乎是正确的。现在，如果我用运行代码lfFaceName="Arial"我为tm和gm得到了以下正确的值:tm.tmHeight=33tm.tmAscent=27tm.tmDescent=6和gm.gmBlackBoxY=15代码:intiLogPixelsY;iLogPixelsY=GetDeviceCaps(hdc,LOGPIXE