INFO: Raster and Stroke Fonts; GDI and Device Fonts (77126)

SUMMARY

NOTE: The information contained in this article does not address TrueType fonts. For information on TrueType fonts, please see chapter 18 of "Guide to Programming" for the Windows SDK version 3.1.

In Windows version 3.0, there are two different ways that the graphical device interface (GDI) can generate characters for a font. For a raster font, GDI displays the font by copying bitmaps to the output device. For a stroke font, GDI displays the font by drawing lines between a series of points that describe each character. Each font is owned by either GDI or by a specific device. Type and ownership information can be determined by enumerating the fonts. This article discusses the two font types and two font ownership types.

MORE INFORMATION

A raster font stores its characters as a series of bitmaps; a stroke font stores its characters as a set of vector operations that describe the characters. When a character from a raster font is drawn, the bitmap is copied onto the device. When a character from a stroke font is displayed, the lines are drawn connecting the points that describe the character. Examples of raster fonts provided with Windows are Courier and Helv; examples of stroke fonts are Script and Roman.

Raster fonts are only available in specific sizes. Some devices can scale installed raster fonts to integer multiples of their size. Use the GetDeviceCaps() function to determine whether the device has this capability. The Windows GDI will scale its raster fonts as required regardless of the device capability. Stroke fonts can be scaled to any size and can also be rotated.

GDI fonts are owned by the GDI; they are available to all devices. Device fonts are fonts that are owned by a particular device; they are available only on that device.

By enumerating the fonts, an application can determine which ones are raster or stroke fonts, and which are GDI or device fonts. The callback function used with EnumFonts() has the parameter nFontType. As stated on page 4-118 of the "Microsoft Windows Software Development Kit Reference Volume 1," the bitwise AND (&) operator can be used with the constants RASTER_FONTTYPE and DEVICE_FONTTYPE to determine the font type. If the RASTER_FONTTYPE bit is set, the font is a raster font; otherwise, it is a stroke font. If the DEVICE_FONTTYPE bit is set, the font is owned by the device that corresponds to the display context handle (HDC) used in the EnumFont() call; otherwise it is a GDI font.