DrvTextOut Accessing Font information

[ssylee]

I'm aware that in the DrvTextOut callback, I can somewhat retrieve
information about the font and its glyphs from pfo member of the parameters,
which are configured in the DrvQueryFont callback. However, I have not
exported this callback in my DDI hooks array, yet I'm getting some numbers
for the pfo members when I investigated this pointer in the debugger. As a
result, I'm not sure what to make out of this. What is the difference between
GDI and driver realized fonts? Basically, after reading the DDK
documentation, I'm still very confused on how I can access the information in
the LOGFONT structure passed in CreateFontIndirect function call in the
client application. Any comments on this would be muchly appreciated.

[Maxim S. Shatskih]

> result, I'm not sure what to make out of this. What is the difference between
> GDI and driver realized fonts?

The glyph data area of the driver-realized font is not known to GDI and is only
known to the driver. You must implement DrvTextOut for it, and DrvTextOut must
have the path to handle this case and to do printing the way the driver wants,
based on the font data generated by the driver itself.

For instance, the driver-realized font can be a font embedded to the printer's
ROM, where the glyph bitmaps are 100% unknown to any host software and do not
appear of the host at all. Driver only knowns the glyph indices and the the
width/kerning pair table, which is embedded to the driver file's resources.

As about GDI fonts - their data is standard, either glyph bitmaps or the
TrueType splines.

--
Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
ma...@storagecraft.com
http://www.storagecraft.com