MORE INFORMATION
The
EnumFontFamiliesEx function is similar to the older
EnumFontFamilies function. Following is the prototype for
EnumFontFamiliesEx:
Int EnumFontFamiliesEx (
HDC hdc, // handle to device context
LPLOGFONT lpLogfont, // pointer to LOGFONT struct
FONTENUMPROC lpEnumFontFamExProc, // pointer to callback function
LPARAM lParam, // application-supplied data
DWORD dWFlags // reserved = 0
);
The lpLogfont points to the LOGFONT structure, which has the information about the fonts for enumeration.
The LOGFONT structure:
typedef struct tagLOGFONT {
LONG lfHeight;
LONG lfWidth;
LONG lfEscapement;
LONG lfOrientation;
LONG lfWeight;
BYTE lfItalic;
BYTE lfUnderline;
BYTE lfStrikeOut;
BYTE lfCharSet;
BYTE lfOutPrecision;
BYTE lfClipPrecision;
BYTE lfQuality;
BYTE lfPitchAndFamily;
TCHAR lfFaceName [LF_FACESIZE];
} LOGFONT;
The lfCharSet parameter specifies the character set. The following values are defined:
ANSI_CHARSET
ARABIC_CHARSET
BALTIC_CHARSET
CHINESEBIG5_CHARSET
DEFAULT_CHARSET
EASTEUROPE_CHARSET
GB2312_CHARSET
GREEK_CHARSET
HANGUEL_CHARSET
HANGUL_CHARSET
HEBREW_CHARSET
JOHAB_CHARSET
MAC_CHARSET
OEM_CHARSET
RUSSIAN_CHARSET
SHIFTJIS_CHARSET
SYMBOL_CHARSET
THAI_CHARSET
TURKISH_CHARSET
VIETNAMESE_CHARSET
If the lfCharSet parameter is set to DEFAULT_CHARSET, the function will enumerate every font in the system as many times as there are Windows character sets supported in this font.
For example, the Arial font shipping with the Microsoft Windows 2000 operating system supports the following nine character sets:
- ANSI_CHARSET
- HEBREW_CHARSET
- ARABIC_CHARSET
- GREEK_CHARSET
- TURKISH_CHARSET
- VIETNAMESE_CHARSET
- BALTIC_CHARSET
- EASTEUROPE_CHARSET
- RUSSIAN_CHARSET
This means that the callback function is called nine times for the Arial font, where on each callback the fields LOGFONT.lfCharSet and TEXTMETRICS.tmCharSet are set to a different charset value from the above set of supported character sets in the Arial font.
If the lfCharSet value on input is set to a value different than DEFAULT_CHARSET, then only those fonts in the system that support this character set will be enumerated. For example, if lfCharSet is set to RUSSIAN_CHARSET, then the Arial font from the above example enumerates and the callback function calls for Arial only once. If lfCharSet value is set to JOHAB_CHARSET on input, the Arial font is not enumerated at all.
The parameter lfFaceName is a null-terminated string that specifies the typeface name of the font. Its length must not exceed 32 characters, including the null terminator. If this is set to an empty string, then the function enumerates one font in each available typeface name.
- lpEnumFontFamExProc: This parameter points to the callback function defined by EnumFontFamExProc().
- lParam: This specifies a 32-bit application-defined value which is passed to the callback function along with font information.
- dwFlags: Must be set to 0.
The EnumFontFamiliesEx() callback function is prototyped in the following manner:
int CALLBACK EnumFontFamExProc (
ENUMLOGFONTEX *lpelfe,
NEWTEXTMETRICEX *lpntme,
int FontType,
LPARAM lParam
);
The lpelfe parameter points to an ENUMLOGFONTEX structure that contains information about the logical attributes of the font. The lpntme parameter also points to a structure that contains information about the physical attributes of a font. Set this to NEWTEXTMETRICEX for TrueType fonts, or TEXTMETRICEX for other fonts.
The callback function is called once for each font name of the TrueType font specified by the lfFaceName in the LOGFONT structure. In addition, it gets multiplicatively called for each script supported by that font. Thus, the callback is made for num_of_font_names X num_of_scripts. However, for non-TrueType fonts, the callback function is called once for each face size supported by that font. The number of face sizes supported by each font differs from those supported by another font, and also varies from machine to machine. For example, if MS Sans Serif supports face sizes 8, 10, 12, 14, 18 and 24 on a particular machine, then the callback function is called 6 times (for the above 6 different face sizes). Although, this is not the case for TrueType fonts since these fonts are continuously scalable and if the callback were done for each size of the TrueType font, then there would be an infinite number of callbacks.
// Sample code:
#include <Windows.H>
#include <StdIO.H>
#include <ConIO.H>
int CALLBACK EnumFontFamiliesExProc( ENUMLOGFONTEX *lpelfe, NEWTEXTMETRICEX *lpntme, int FontType, LPARAM lParam )
{
printf( "%s\n", lpelfe->elfFullName );
return 1;
}
int main( int __argc, char** __argv )
{
HDC hDC = GetDC( NULL );
LOGFONT lf = { 0, 0, 0, 0, 0, 0, 0, 0, DEFAULT_CHARSET, 0, 0, 0,
0, "Courier New" };
EnumFontFamiliesEx( hDC, &lf, (FONTENUMPROC)EnumFontFamiliesExProc, 0, 0 );
ReleaseDC( NULL, hDC );
return 0;
}