Stats

  • Locked Locked
  • Replies 4
  • Subscribers 144
  • Views 15798
  • Members are here 0
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

polygon subtraction

drdanmc

I was working on some skill code to generate a logo for a sheet symbol and ended up in a spot where I need to subtract two polygons.  My preference is to operate on the lists  of points that define the two polygons:

points1 = list(0:0 10:0 10:10 0:10 0:0)

points2=list(2:2 8:2 8:8 2:8 2:2)

points3 = myPolyptsSub(points1, points2) ;; not sure how to implement

fig=dbCreatePolygon(cv, my_lpp, points3)

alternatively, I could live with

fig1 = dbCreatePolygon(cv, my_lpp, points1)

fig2 = dbCreatePolygon(cv, my_lpp, points2)

fig3 = dbLayerAndNot(cv, my_lpp, list(fig1), list(fig2))

dbDeleteObject(fig1)

dbDeleteObject(fig2)

;; is there a db* function to merge the geometries that come back or only the leMergeShapes() function

;; in fig3 (which should be a list)

but it would be nice to be able to work directly with the points.

The reason I'm interested in working directly with points is I have some code that takes an SVG path specification string and turns it into polygon points but some cases may involve an outside shape with some cutouts.  My real case is more complicated than just a square cut out of a square.  Think polygons with hundreds of points.

Thanks for any suggestions.

-Dan

Parents
  • Thanks! I had missed the dbPointArray* functions. I find it interesting that those functions need a cellview ID even though they don't actually modify the cellview. I would have thought those would strictly work on points.

    but this seems to work

    points3 = dbPointArrayXor(cv list(points1) list(points2))
    foreach(p points3
    dbCreatePolygon(cv, my_lpp, p)
    )


    -Dan
Reply
  • Thanks! I had missed the dbPointArray* functions. I find it interesting that those functions need a cellview ID even though they don't actually modify the cellview. I would have thought those would strictly work on points.

    but this seems to work

    points3 = dbPointArrayXor(cv list(points1) list(points2))
    foreach(p points3
    dbCreatePolygon(cv, my_lpp, p)
    )


    -Dan
Children
No Data

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.