Algorithms to find the convex hull of a set of points in a plane. Also generates points useful for testing itself.
Clone the repo. Use Gradle to build the standalone JAR.
$ gradle shadowJar
Run the standalone JAR file.
$ java -jar build/libs/convex-hull-1.0-all.jar <args>
See the next section for the arguments.
To find the convex hull of points in a file, specify two arguments:
$ java -jar build/libs/convex-hull-1.0-all.jar <path to file> <algorithm>
The <algorithm> must be one of the following values:
- gs: Graham Scan
- jm: Jarvis March
The file should contain pairs of x-y coordinates separated by spaces. There should be one pair per line. Lines starting with # will be ignored.
The convex hull will be output to standard output.
The program can also generate a set of points. To do this, specify two arguments
$ java -jar build/libs/convex-hull-1.0-all.jar <number of points> <max x or y coord>
Finding the convex hull using Graham Scan for points in the file at /home/user/points.dat:
$ java -jar build/libs/convex-hull-1.0-all.jar /home/user/points.dat gs
You can redirect the output to a file:
$ java -jar build/libs/convex-hull-1.0-all.jar /home/user/points.dat gs > /home/user/output.dat
Generating 1000 in the plane bounded by (0,0), (0,50), (50,0), and (50,50):
$ java -jar build/libs/convex-hull-1.0-all.jar 1000 50
Of course, you can redirect the points to a file as well:
$ java -jar build/libs/convex-hull-1.0-all.jar 1000 50 > /home/user/test.dat
The Jarvis March implementation does not handle collinear points properly.
You can use gnuplot to plot the output of this program
Plotting points:
gnuplot> plot '~/convex-hull/points.dat' with points pointtype 7
Plotting lines:
gnuplot> plot '~/convex-hull.dat' with linespoints ls 1
Copyright © 2016 Corey Beres
Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.