XPLM_API void       XPLMDrawNumber(
                         float *              inColorRGB,    
                         int                  inXOffset,    
                         int                  inYOffset,    
                         double               inValue,    
                         int                  inDigits,    
                         int                  inDecimals,    
                         int                  inShowSign,    
                         XPLMFontID           inFontID);    

This routine draws a number similar to the digit editing fields in PlaneMaker and data output display in X-Plane. Pass in a color, a position, a floating point value, and formatting info. Specify how many integer and how many decimal digits to show and whether to show a sign, as well as a character set. This routine returns the xOffset plus width of the string drawn.