1. A method of picking an image on a display screen, comprising the steps of: (a) displaying a pick marker on said display screen; (b) directing said pick marker at an image on said display screen for picking said image, said image comprising at least one line primitive, said at least one line primitive having end-point coordinates x.sub.1, y.sub.1 and x.sub.2,y.sub.2 on an x-y coordinate system, said pick marker having a diamond shaped pick window corresponding thereto, and said diamond shaped pick window having a first diagonal with a length of 2h and a second diagonal with a length of 2w; (c) subjecting said at least one line primitive to a trivial test, said trivial test comprising enclosing said diamond shaped pick window in a least enclosing rectangle, wherein said diamond shaped pick window and said rectangle have a common center point, and rejecting said at least one line primitive if said at least one line primitive has both of its end-points outside of the same extended edge of said rectangle; (d) if said at least one line primitive cannot be trivially tested in step (c), subjecting said at least one line primitive to a non-trivial test which does not require performing floating point operations, and accepting or rejecting said at least one line primitive in accordance with the results of said non-trivial test; (e) considering accepted line primitives as being selected; and, (f) selecting said image on said display corresponding to said selected line primitives for further processing.