#ifndef _TEXTMETRIC_DEFINED#define _TEXTMETRIC_DEFINEDtypedef struct tagTEXTMETRICA{ LONG tmHeight; LONG tmAscent; LONG tmDescent; LONG tmInternalLeading; LONG tmExternalLeading; LONG tmAveCharWidth; LONG tmMaxCharWidth; LONG tmWeight; LONG tmOverhang; LONG tmDigitizedAspectX; LONG tmDigitizedAspectY; BYTE tmFirstChar; BYTE tmLastChar; BYTE tmDefaultChar; BYTE tmBreakChar; BYTE tmItalic; BYTE tmUnderlined; BYTE tmStruckOut; BYTE tmPitchAndFamily; BYTE tmCharSet;} TEXTMETRICA, *PTEXTMETRICA, NEAR *NPTEXTMETRICA, FAR *LPTEXTMETRICA;typedef struct tagTEXTMETRICW{ LONG tmHeight; LONG tmAscent; LONG tmDescent; LONG tmInternalLeading; LONG tmExternalLeading; LONG tmAveCharWidth; LONG tmMaxCharWidth; LONG tmWeight; LONG tmOverhang; LONG tmDigitizedAspectX; LONG tmDigitizedAspectY; WCHAR tmFirstChar; WCHAR tmLastChar; WCHAR tmDefaultChar; WCHAR tmBreakChar; BYTE tmItalic; BYTE tmUnderlined; BYTE tmStruckOut; BYTE tmPitchAndFamily; BYTE tmCharSet;} TEXTMETRICW, *PTEXTMETRICW, NEAR *NPTEXTMETRICW, FAR *LPTEXTMETRICW;#ifdef UNICODEtypedef TEXTMETRICW TEXTMETRIC;typedef PTEXTMETRICW PTEXTMETRIC;typedef NPTEXTMETRICW NPTEXTMETRIC;typedef LPTEXTMETRICW LPTEXTMETRIC;#elsetypedef TEXTMETRICA TEXTMETRIC;typedef PTEXTMETRICA PTEXTMETRIC;typedef NPTEXTMETRICA NPTEXTMETRIC;typedef LPTEXTMETRICA LPTEXTMETRIC;#endif // UNICODE#endif // !_TEXTMETRIC_DEFINED
GetTextMetrics（hdc,&tm)函数来确定字体大小
BOOL GetTextMetrics( HDC hdc, // handle to device context
LPTEXTMETRIC lptm // pointer to text metrics structure
);
If the function succeeds, the return value is nonzero.
If the function fails, the return value is zero.
