| WORD EnumDFonts(lpDestDev, lpFaceName, lpCallbackFunc, lpClientData) | |||||
| LPPDEVICE lpDestDev; | /* points to physical device or bitmap | */ | |||
| LPSZ lpFaceName; | /* points to name of font face | */ | |||
| FARPROC lpCallbackFunc; | /* points to user-supplied callback function | */ | |||
| LPVOID lpClientData; | /* points to user-supplied data | */ | |||
The EnumDFonts function returns information about device fonts by passing the information to the specified callback function. GDI calls this function when processing the EnumFonts function (GDI.70) to determine what device fonts are available.
Every graphics driver must export an EnumDFonts function.
lpDestDev
Points to a PDEVICE or PBITMAP structure.
lpFaceName
Points to the null-terminated string specifying the name of a font. If lpFaceName points to a name, EnumDFonts calls the callback function with information for the fonts having the same font name. If there are no fonts of that name, the function returns 1.
If lpFaceName is NULL, EnumDFonts randomly selects one font of each name and calls the callback function with information for these fonts. If there are no fonts, the function returns 1.
lpCallbackFunc
Points to a user-supplied callback function. For more information about the callback function, see the following “Comments” section.
lpClientData
Points to a buffer containing user-supplied data. EnumDFonts does not use this data; instead it passes the data back to application through the callback function.
The return value is the last value returned by the callback function. The function returns 1 if there are no fonts having the specified font name.
The export ordinal for this function is 6.
EnumDFonts calls the callback function once for each font. It continues to call the callback function until there are no more fonts, or the callback function returns zero.
The callback function has the following form:
WORD CallbackFunction(lpLogFont, lpTextMetrics,
wFontType, lpClientData)
LPLFONT lpLogFont;
LPTEXTMETRICS lpTextMetrics;
WORD wFontType;
LPVOID lpClientData;
| Parameter | Description |
| lpLogFont | Points to a LFONT structure defining the logical attributes of a font. All sizes are in device units. | ||
| lpTextMetrics | Points to a TEXTMETRIC structure containing the same values that would be returned by the GetTextMetrics (GDI.93) function. All sizes are in device units. | ||
| wFontType | Specifies the type of the font. It can be one of the following values. | ||
| Value | Meaning | ||
| RASTER_FONTTYPE (1) | Font consists of raster bitmaps rather than vector strokes. |
| DEVICE_FONTTYPE (2) | Font is provided by the device rather than GDI. |
| ENGINE_FONTTYPE (4) | Font is provided by TrueType rather than GDI or device. |
| Bit 3 in the wFontType parameter is reserved; must be zero. | |
| lpClientData | Points to the user-supplied data passed to EnumDFonts. |
The callback function must return a nonzero value to continue to receive information about the fonts. If the callback function returns zero, EnumDFonts stops enumerating the fonts and returns to GDI.
If the device can generated scaled, bold, or italicized fonts, EnumDFonts should pass only the information about the base font to the callback function. EnumDFonts should then leave it to the application to inquire about the device's text transformation abilities.