Typically, a user will call GDI.InitLogFont first to set all font fields to their default values, and then modify whichever field needs changing.
Because the font structure consists of Internet Basic strings, the INTEL/INTELD functions must be used to effect any modifications. For an example see the GDI.InitLogFont function in the usefile #LOGFNT.
Some commonly modified fields are:
| lfHeight$ | Font size in 10th's of a point (inch/72). The font mapper looks for the largest font that does not exceed the requested size; if there is no such font, it looks for the smallest font available. |
| lfWidth$ | Specifies the average width, in logical units, of characters in the font. If lfWidth is zero, the aspect ratio of the device is matched against the digitization aspect ratio of the available fonts to find the closest match, determined by the absolute value of the difference. |
| lfEscapement$ | Specifies the angle, in tenths of degrees, of each line of text written in the font (relative to the bottom of the page). |
| lfOrientation$ | Specifies the angle, in tenths of degrees, of each character's base line (relative to the bottom of the page). |
| lfWeight$ | Darkness (or lightness) of the characters |
| lfItalic$ | Specifies an italic font if set to TRUE. |
| lfUnderline$ | Specifies an underlined font if set to TRUE. |
| lfStrikeOut$ | Specifies a strikeout font if set to TRUE. |
| lfFaceName$ | Desired font face ("Arial", "Courier New", etc.) |