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

   1 more example

   The geometric pen and geometric chuck, in point of mechanical contrivance, are necessarily as different as two instruments, giving to a certain extend similar results, can possibly be; and they act upon diametrically opposite principles;

   1829, Mechanics' Magazine, Museum, Register, Journal, and Gazette

2. computer graphicsA 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.

   To be more specific, a geometric pen has a scalable width, different styles, end caps, and joins.

   2001, Feng Yuan, Windows Graphics Programming: Win32 GDI and DirectDraw, page 468

   1 more example

   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