COS226

• Download PercolationVisualizer.java

/* *****************************************************************************
 *  Compilation:  javac-algs4 PercolationVisualizer.java
 *  Execution:    java-algs4 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 (initially all blocked)
 *    - Reads in a sequence of sites (row, col) 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 edu.princeton.cs.algs4.In;
import edu.princeton.cs.algs4.StdDraw;

import java.awt.Font;

public class PercolationVisualizer {

    // delay in milliseconds (controls animation speed)
    private static final int DELAY = 100;

    // draw n-by-n percolation system
    public static void draw(Percolation percolation, int n) {
        StdDraw.clear();
        StdDraw.setPenColor(StdDraw.BLACK);
        StdDraw.setXscale(-0.05 * n, 1.05 * n);
        StdDraw.setYscale(-0.05 * n, 1.05 * n);   // leave a 5% border
        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 (percolation.isFull(row, col)) {
                    StdDraw.setPenColor(StdDraw.BOOK_LIGHT_BLUE);
                }
                else if (percolation.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(0.25 * n, -0.025 * n, percolation.numberOfOpenSites() + " open sites");
        if (percolation.percolates()) StdDraw.text(0.75 * n, -0.025 * n, "percolates");
        else StdDraw.text(0.75 * n, -0.025 * n, "does not percolate");

    }

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

        // turn on animation mode
        StdDraw.enableDoubleBuffering();

        // repeatedly read in sites to open and draw resulting system
        draw(percolation, n);
        StdDraw.show();
        StdDraw.pause(DELAY);

        while (!in.isEmpty()) {
            int row = in.readInt();
            int col = in.readInt();
            percolation.open(row, col);
            draw(percolation, n);
            StdDraw.show();
            StdDraw.pause(DELAY);
        }
    }

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