DOCERR: _getfontinfo() and Vector Mapped Fonts

MS-DOS                 | OS/2       | WINDOWS

The information in this article applies to:

• The C Run-time (CRT), included with:

      - Microsoft C for MS-DOS, versions 6.0, 6.0a, and 6.0ax
      - Microsoft C for OS/2, versions 6.0 and 6.0a
      - Microsoft C/C++ for MS-DOS, version 7.0
      - Microsoft Visual C++ for Windows, version 1.0
  

SUMMARY

_getfontinfo() is documented as returning a _fontinfo structure containing information including type, facename, filename, ascent, pixheight, pixwidth, and avgwidth about the font currently set. However, _getfontinfo() only reads these values from the .FON file in which they are stored. This can cause problems when using vector fonts that have been scaled by the _setfont() function because the values for ascent, pixheight, and avgwidth will probably be incorrect.

MORE INFORMATION

Vector fonts are stored in the .FON file as a series of equations that can be multiplied by some scaling factor to generate fonts of different sizes. By default, the scale factor is 1. When _getfontinfo() is called, it will always return the values for ascent, pixheight, and avgwitch assuming the default scale factor. If the font is scaled to some type size other than the default [using _setfont() with WxHy parameters], the new values for ascent, pixheight, and avgwidth will need to be recalculated. The factor can be determined by dividing the pixheight value returned from _getfontinfo() by the Hy parameter passed to _setfont().