AutoLISP Developer's Guide > Using the AutoLISP Language > Using AutoLISP to Communicate with AutoCAD > Display Control > 
Control of Low-Level Graphics
 
 
 

AutoLISP provides functions that control the low-level graphics and allow direct access to the AutoCAD graphics screen and input devices.

The grtext function displays text directly in the status or menu areas, with or without highlighting. The grdraw function draws a vector in the current viewport with control over color and highlighting. The grvecs function draws multiple vectors.

NoteBecause these functions depend on code in AutoCAD, their operation can be expected to change from release to release. There is no guarantee that applications calling these functions will be upward compatible. Also, they depend on current hardware configurations. In particular, applications that call grtext are not likely to work the same on all configurations unless the developer is very careful to use them as described (see the Customization Guide) and to avoid hardware-specific features. Finally, because they are low-level functions, they do almost no error reporting and can alter the graphics screen display unexpectedly (see the following example for a way to fix this).

The following sequence restores the default graphics window display caused by incorrect calls to grtext, grdraw, or grvecs:

(grtext)	 Restores
standard text

(redraw)