1    /* 
2     * A program to paint an abstract gradient in the vertical direction. 
3     */
4    
5    package npw;
6    
7    import painter.SPainter;
8    import shapes.SCircle;
9    
10   import javax.swing.*;
11   import java.awt.*;
12   import java.util.Random;
13   import java.util.Scanner;
14   
15   import static javax.swing.SwingUtilities.*;
16   
17   public class ColorfulAbstractGradient {
18   
19       public static void main(String[] args) {
20           invokeLater( ColorfulAbstractGradient::new );
21       }
22   
23       private ColorfulAbstractGradient() {
24           paintTheImage();
25       }
26   
27       private void paintTheImage(){
28           // Grab the input information
29           int width = getNumber("width");
30           int height = getNumber("height");
31           int colWidth = getNumber("column width");
32           // Establish the painter
33           SPainter painter = new SPainter("Colorful Abstract Gradient", width, height);
34           SCircle dot = new SCircle(5);
35   
36           // Move the painter to the upper left corner to get ready to paint the gradient
37           painter.mfd(height/2);
38           painter.tl(90);
39           painter.mfd(width/2 - 10);
40           painter.tl(90);
41   
42           // Paint it!
43           paintGradient(painter, dot, height, width, colWidth);
44       }
45   
46       private static int getNumber(String prompt) {
47           String nss = JOptionPane.showInputDialog(null,prompt+"?");
48           Scanner scanner = new Scanner(nss);
49           return scanner.nextInt();
50       }
51   
52       private void paintGradient(SPainter painter, SCircle dot, int height, int width, int colWidth){
53           int cols = 0;
54           // Calculate the number of columns. We want to fill the screen, but we don't want
55           // any dots only half on the canvas, so we subtract some space.
56           int nrOfCols = ( width / colWidth ) - 2;
57           while (cols < nrOfCols){
58               nextCol(painter, colWidth);
59               paintColumn(painter, dot, height);
60               cols = cols + 1;
61           }
62       }
63   
64       private void paintOneDot(SPainter painter, SCircle dot){
65           // Change color before painting
66           painter.setColor(randomColor());
67           painter.paint(dot);
68       }
69       // Dots are spaced tighter together near the bottom of the canvas.
70       private void paintColumn(SPainter painter, SCircle dot, int height) {
71           int travel = 0;
72           int totalDistanceTraveled = 0;
73   
74           // Paint a row with decreasing distance between dots.
75           while(totalDistanceTraveled < height - (dot.radius() * 3)) {
76               travel = randomDistance((height - totalDistanceTraveled) / 4);
77               totalDistanceTraveled = totalDistanceTraveled + travel;
78               painter.mfd(travel);
79               paintOneDot(painter, dot);
80           }
81   
82           // Make the method invariant with respect to painter position.
83           painter.mbk(totalDistanceTraveled);
84       }
85       // Moves the painter to the next column.
86       private void nextCol(SPainter painter, int colWidth){
87           painter.tl(90);
88           painter.mfd(colWidth);
89           painter.tr(90);
90       }
91       private int randomDistance(int maxDistance){
92           Random rgen = new Random();
93           return rgen.nextInt(maxDistance);
94       }
95   
96       // A random color method has to be made
97       private Color randomColor(){
98           Random rgen = new Random();
99           int r = rgen.nextInt(255); // bound of 0-255
100          int g = rgen.nextInt(255);
101          int b = rgen.nextInt(255);
102          return new Color(r,g,b);
103      }
104  }