4.1.15 Device Fonts

The most common type of device object is a device font. Most printers are capable of printing some set of built-in fonts. The concept of device fonts enables drivers and applications to take advantage of a device's ability to render fonts. Device fonts are also expected to print faster and look better than GDI fonts.

To determine what device fonts are available, GDI calls the EnumDFonts function and expects the printer driver to enumerate the fonts. Typically, GDI first calls EnumDFonts passing an empty string for the font name. This indicates that the driver should enumerate each font name that it supports. On subsequent calls, GDI passes one of enumerated font names and expects the driver to enumerate all the sizes of that font.

Printer drivers may also wish to support GDI raster and vector fonts. For banding devices, it is usually not difficult to support GDI raster fonts because GDI contains support functions to render raster fonts into monochrome-band bitmaps. GDI raster fonts are most useful for devices (such as lower-resolution dot-matrix printers) with resolutions near those of the display.

For nonbanding devices, supporting GDI raster fonts is not as easy. In fact, the PostScript driver (a nonbanding device) does not support GDI raster fonts.

Supporting vector fonts is also optional. If a driver does not support vector fonts, GDI will simulate them by drawing line segments.