V27 and Lee Mac's GrSnap Lisp

Jerryfiedler
Jerryfiedler
in LISP

Greetings,

I have several lisp routines that use Lee Mac's GrSnapV1-0.lsp. It is a terrific program that I have used with AutoCAD, in years past, and now with BricsCAD. https://www.lee-mac.com/grsnap.html

Coming from Autolisp to Bricslisp (?) I learned from a forum post that the line in LM:grsnap:displaysnap function that translates the mouse coordinates from UCS to DCS had to be deleted (setq pnt (trans pnt 1 2)). This is because BricsCAD does not use the DCS for grvecs. This very simple modification made Lee's program work flawlessly in BricsCAD V25 and V26.

Now after installing V27 the snap symbol is offset in both x and y directions. The offset amount varies as you zoom in and out. This makes sense since there is a scale factor in the grvecs transformation matrix. I have tried various adjustments to the code but have found no solution.

I assume BricsCAD programmers made some changes to the graphic engines that might be causing this problem. I would appreciate all comments and suggestions that might get this great program working again.