When generating characters for Direct Graphics plots, IDL uses the font system specified by setting the !P.FONT system variable to one of the following values:


Use Hershey vector-drawn fonts—the default


Use device fonts (fonts supplied by the graphics device)


Use TrueType fonts

The IDL system variable !P.FONT setting can be overridden for a single IDL Direct Graphics routine (AXIS, CONTOUR, PLOT, SHADE_SURF, SURFACE, or XYOUTS) by setting the FONT keyword equal to -1, 0, or 1.

Once a font system has been selected, an individual font can be chosen either via a formatting command embedded in a text string as described in Embedded Formatting Commands, or by setting the value of the SET_FONT keyword to the DEVICE routine (see SET_FONT). Also see Using TrueType Fonts and Using Device Fonts for additional examples of using SET_FONT.