README.md

Line Intersection Project

Setup

In a working python3 environment (preferably virtualenv) run the setup script

$ source setup.sh

Testing and Running the program

Create a text file with line segments, where each line segment is contained on a new line. Look at tests/test.txt for an example. To run the plane sweep algorithm for line intersection run the following command

$ python3 main.py [test_file] --plane-sweep

To run the brute force implementation, disregard the --plane-sweep flag.

Visualisation

main.py itself opens the visualisation interface. Alternatively, running the following also works

$ python3 main.py --plane-sweep

The interface works as follows:

Inserting Line Segments

1. Click on the "+" button at the bottom right.
2. Click at any location to insert a point. Move the mouse cursor to the other end point and click to add the line segment. Repeat the clicking and moving to add more line segments. Press <ESC> at any stage to cancel the insertion.
3. Undoing and redoing line segment insertions: C-z and C-r undo and redo the insertion of line segments, respectively. (C- denotes pressing the control key as a modifier)
4. Pressing C-s saves the line segments into the tests/ folder. This file can be loaded via the same program again using the [test_file] argument as described above.

Running the Algorithm

1. Once the line segments are added, click <ENTER> to run the corresponding algorithm.
2. If the algorithm has already been run, then clicking <ENTER> highlights the intersection points red.
3. Clicking <BACKSPACE> clears the screen and resets to just the line segments

Visualising the steps

1. Alternatively, click the left and right buttons present at the bottom left of the screen to move backwards and forwards in execution
2. Pressing <ESC> at any stage resets the progress in the algorithm and hence going back to the start

Quitting the visualisation interface

Press q to quit the visualisation interface.