PercolationVisualizer.java

/******************************************************************************
 *  Compilation:  javac PercolationVisualizer.java
 *  Execution:    java PercolationVisualizer input.txt
 *  Dependencies: Percolation.java
 *
 *  This program takes the name of a file as a command-line argument.
 *  From that file, it
 *
 *    - Reads the grid size N of the percolation system.
 *    - Creates an N-by-N grid of sites (intially all blocked)
 *    - Reads in a sequence of sites (row i, column j) to open.
 *
 *  After each site is opened, it draws full sites in light blue,
 *  open sites (that aren't full) in white, and blocked sites in black,
 *  with with site (0, 0) in the upper left-hand corner.
 *
 ******************************************************************************/
import java.awt.Font;

import edu.princeton.cs.algs4.In;
import edu.princeton.cs.algs4.StdDraw;

public class PercolationVisualizer {
    // delay in miliseconds (controls animation speed)
    private static final int DELAY = 100;

    // draw N-by-N percolation system
    public static void draw(Percolation perc, int N) {
        StdDraw.clear();
        StdDraw.setPenColor(StdDraw.BLACK);
        StdDraw.setXscale(-.05 * N, 1.05 * N);
        StdDraw.setYscale(-.05 * N, 1.05 * N);   // leave a border to write text
        StdDraw.filledSquare(N / 2.0, N / 2.0, N / 2.0);

        // draw N-by-N grid
        for (int row = 0; row < N; row++) {
            for (int col = 0; col < N; col++) {
                if (perc.isFull(row, col)) {
                    StdDraw.setPenColor(StdDraw.BOOK_LIGHT_BLUE);
                } else if (perc.isOpen(row, col)) {
                    StdDraw.setPenColor(StdDraw.WHITE);
                } else {
                    StdDraw.setPenColor(StdDraw.BLACK);
                }
                StdDraw.filledSquare(col + 0.5, N - row - 0.5, 0.45);
            }
        }

        // write status text
        StdDraw.setFont(new Font("SansSerif", Font.PLAIN, 12));
        StdDraw.setPenColor(StdDraw.BLACK);
        StdDraw.text(.25 * N, -N * .025, perc.numberOfOpenSites() + " open sites");
        if (perc.percolates()) {
            StdDraw.text(.75 * N, -N * .025, "percolates");
        } else {
            StdDraw.text(.75 * N, -N * .025, "does not percolate");
        }
    }

    // this is the implementation of deprecated StdDraw.show(int t)
    public static void show(int t) {
        StdDraw.show();
        StdDraw.pause(t);
        StdDraw.enableDoubleBuffering();
    }

    private static void simulateFromFile(String filename) {
        In in = new In(filename);
        int N = in.readInt();
        Percolation perc = new Percolation(N);

        // turn on animation mode
        show(0);

        // repeatedly read in sites to open and draw resulting system
        draw(perc, N);
        show(DELAY);
        while (!in.isEmpty()) {
            int i = in.readInt();
            int j = in.readInt();
            perc.open(i, j);
            draw(perc, N);
            show(DELAY);
        }
    }

    public static void main(String[] args) {
        String filename = args[0];
        simulateFromFile(filename);
    }

}