Draws a vector in the currently active
image. The relevant dimensions of the image can be fetched with
dimx_tile and dimy_tile. Those dimensions can be used to calculate
the desired dimensions of the vector. The colorcode is either a dwg
color index as it is commonly used in CAD applications or it is one
of the special purpose DCL color codes. Examples of dwg color
indices are 1 for red, 2 for yellow, 5 for blue. The special
purpose DCL color codes are negative integers. These are the
special purpose DCL color codes: -2 background color of the CAD
graphics screen -15 background color of the DCL dialog -16
foreground color of the DCL dialog -18 line color of the DCL
dialog