## Display Device Driver Reference for OS/2

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### PM Display Driver

The PM display driver no longer has any DBCS device fonts. All of the DBCS device fonts are provided by the font drivers and supplied to the PM display driver by the font manager.

The PM display driver needs to handle:

Notification to the engine to handle device font management on the device driver side. (This is not true for SBCS drivers.)

Font manager initialization at startup time

Default font selection for GPI and VIO fonts

Font manager invocation according to the PDI (Presentation Driver Interface) function called

SBCS device fonts (system proportional fonts) management

Additionally, the display device driver should include the following functions:

Text query functions (such as TextBox, CharPositions, and WidthTable functions, which are not included in SBCS drivers)

Text parsing according to the code page to use (the parser must call the font manager to construct a valid fontseg when the string includes DBCS code points)

The following functions are no longer needed:

Loading and unloading DBCS device font drivers

Creating and destroying DBCS logical fonts. (These functions are handled by the font manager.)

DBCS handling in text output routine. (The fontseg passed from the font manager is always in the form of SBCS proportional.)