geometric pens

Noun

geometric pen (plural geometric pens)

1. An instrument for drawing geometric curves, in which the movements of a pen or pencil attached to a revolving arm of adjustable length may be indefinitely varied by changing the toothed wheels which give motion to the arm.
   • But it may be proper to take some notice of the geometric pen, as it is not so well known , nor the principles on which it depends so obvious .1797, Colin Macfarquhar, George Gleig, Encyclopædia Britannica, page 116
2. A configurable drawing tool for creating lines that has a width specified in logical units, as opposed to device units (pixels), and therefore scales when the resulting image is zoomed in or out.
   • The classic example of using geometric and cosmetic pens is in architectural drawing: You'd use a geometric pen for drawing the walls of the building. If you then zoom in on the drawing using a transform, the walls will appear wider, as they should.1994 January 25, Charles Petzold, “Extended Pen Creation Under Windows NT”, in PC Magazine, volume 13, number 2, page 291