This page is first released 1-01-98
Last Page Update: 3-3-2007
Boolean: GDSII viewer/editor + (boolean) operations on sets of 2d polygons.                        

Operations (some)

original merge    a-b b-a intersect  exor makering negative_cor positive_cor
Index
Introduction
The program is a viewer and editor for: Mainly the program is used in the electronic chip design industry. But it it offers much more then that. Many effort has gone in automating the jobs to be done.
Therefore the commands isued by the GUI, go through a command interpreter as ASCII strings, in order to record them and replay it them afterwords.

Features:

Next to this it contains several algorithms for performing 2D polygon operations (boolean, offset, arc recognition etc.). All the primitives are situated on layers. The operations take two sets of layers (each set containing all primitives on the selected layers). The sets are the operands of the (boolean) operation, a destination layer is chosen to contain the result of the operation.

Operation:

The C++ source code, executables  and sample files are available.
 
Copyright License?
The code is written by Klaas Holwerda,  it is free to use for non commercial open source projects licensed as GPL.
If you need a commercial license, contact me.- mail me .
 
The C++ Source and executables and documentation
Download PAGE

Feedback In case of problems installing etc. and for  remarks, suggestions and bug fixes - mail me .
Also i always appreciate some feedback on where this program is used for, or what you think of it.
 
Documentation Technical

The algorithm description

The basis of the boolean algorithms is scanlines. For the basic principles the book: Computational Geometry an introduction by Franco P Preparanta and Michael Ian Shamos is very good. For the rest many sources gave small hints into the final direction the algorithms were implemented.
The documentation explains the principles of the algorithm, i am working on a new version of this document.
But it evolves more quickly (for sure the ideas), to keep up with it.
See COMPLETE BOOLEAN DISCRIPTION   to see a more detailed description.
Roughly the following steps are involved for performing a boolean operation:
  1. convert all polygons to graph structures
  2. combine all graph segments in to one big graph
  3. calculate all intersections between the graphs using a scanbeam and insert them as extra vertices/segments
      1. first at 0 degrees angle, snapping vertices and lines that are within the snapping range in vertical direction.
      2. secondly at 90 degrees angle, snapping vertices and lines that are within the snapping range in horizontal direction.

      3. (just swapping x,y coordinates)
  4. set appropriate segment flags for all boolean operations at once using a scanbeam
  5. extract for the given boolean operation the resulting graphs (hole graphs and outside graphs).
  6. link holes into outside graphs using a scanbeam.
  7. extract resulting polygons from the graph structures again
Command documentation
  • Command overview
  • Graphical Interface


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