1    /* 
2     * A program to paint a colorful 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   public class ColorfulAbstractGradient {
16   
17       public static void main(String[] args) {
18           SwingUtilities.invokeLater(ColorfulAbstractGradient::new);
19       }
20   
21       public ColorfulAbstractGradient() {
22           paintTheImage();
23       }
24   
25       private void paintTheImage(){
26           // Grab the input information
27           int width = getNumber("width");
28           int height = getNumber("height");
29           int colWidth = getNumber("column width");
30           // Establish the painter
31           SPainter painter = new SPainter("Colorful Abstract Gradient", width, height);
32           SCircle dot = new SCircle(5);
33   
34           // Move the painter to the upper left corner to get ready to paint the gradient
35           painter.mfd(height/2);
36           painter.tl(90);
37           painter.mfd(width/2 -10);
38           painter.tl(90);
39   
40           // Paint it!
41           paintGradient(painter, dot, height, width, colWidth);
42       }
43   
44       private static int getNumber(String prompt) {
45           String nss = JOptionPane.showInputDialog(null,prompt+"?");
46           Scanner scanner = new Scanner(nss);
47           return scanner.nextInt();
48       }
49   
50       private void paintGradient(SPainter painter, SCircle dot, int height, int width, int colWidth){
51           int cols = 0;
52           // Calculate the number of columns.
53           int nrOfCols = ( width / colWidth - 2);
54   
55           while (cols < nrOfCols){
56               nextCol(painter, colWidth);
57               paintColumn(painter, dot, height);
58               cols = cols + 1;
59           }
60       }
61   
62       private void paintOneDot(SPainter painter, SCircle dot){
63           randomColor(painter);
64           painter.paint(dot);
65       }
66   
67       // Dots are spaced tighter together near the bottom of the canvas.
68       private void paintColumn(SPainter painter, SCircle dot, int height) {
69           int travel = 0;
70           int totalDistanceTraveled = 0;
71   
72           // Paint a row with decreasing distance between dots.
73           while(totalDistanceTraveled < height - (dot.radius() * 3)) {
74               travel = randomDistance((height - totalDistanceTraveled) / 4);
75               totalDistanceTraveled = totalDistanceTraveled + travel;
76               painter.mfd(travel);
77               paintOneDot(painter, dot);
78           }
79   
80           // Make the method invariant with respect to painter position.
81           painter.mbk(totalDistanceTraveled);
82       }
83   
84       // Moves the painter to the next column.
85       private void nextCol(SPainter painter, int colWidth){
86           painter.tl(90);
87           painter.mfd(colWidth);
88           painter.tr(90);
89       }
90   
91       private int randomDistance(int maxDistance){
92           Random rgen = new Random();
93           return rgen.nextInt(maxDistance);
94       }
95   
96       private void randomColor(SPainter painter) {
97           Random colorful = new Random();
98           int r = colorful.nextInt(255);
99           int g = colorful.nextInt(255);
100          int b = colorful.nextInt(255);
101         painter.setColor(new Color(r,g,b));
102      }
103  }
104