1 /*
2 * File: DrawablePolygon.java
3 *
4 * Custom polygon class for Java 1.1
5 *
6 * Copyright: Northeast Parallel Architectures Center
7 *
8 */
9
10 import java.awt.Polygon;
11 import java.awt.Color;
12 import java.awt.Point;
13 import java.awt.Graphics;
14 import java.awt.Component;
15
16 /*
17 * DrawablePolygon inherits variables xpoints[], ypoints[],
18 * npoints and bounds, and numerous methods from Polygon
19 *
20 */
21
22 public class DrawablePolygon extends Polygon implements Drawable {
23
24 // instance variable:
25 private Color color;
26
27 // DrawablePolygon constructor #1:
28 public DrawablePolygon() {
29
30 // invoke the no-argument constructor of the superclass:
31 super();
32
33 }
34
35 // DrawablePolygon constructor #2 (for compatibility with Polygon):
36 public DrawablePolygon( int[] xpoints, int[] ypoints, int npoints ) {
37
38 // invoke a constructor of the superclass:
39 super( xpoints, ypoints, npoints );
40
41 }
42
43 // DrawablePolygon constructor #3:
44 public DrawablePolygon( Point[] points, int npoints ) {
45
46 // invoke DrawablePolygon constructor #1:
47 this();
48
49 for ( int i = 0; i < npoints; i++ ) {
50 this.addPoint( points[i] ); // TEST!
51 }
52
53 }
54
55 /*
56 * DrawablePolygon constructor #4
57 *
58 * A regular n-gon with center (x,y) and radius r
59 *
60 */
61
62 public DrawablePolygon( int x, int y, int r, int n ) {
63
64 // invoke DrawablePolygon constructor #1:
65 this();
66
67 // rotation angle:
68 double theta = 2 * Math.PI/n;
69
70 // initial point is at twelve o'clock:
71 DrawablePoint p = new DrawablePoint( 0, -r );
72 this.addPoint( p );
73 for ( int i = 1; i < n; i++ ) {
74 // rotate the previous point:
75 p = p.rotate( theta );
76 this.addPoint( p );
77 }
78 this.translate( x, y );
79
80 }
81
82 // implement the methods of the Drawable interface:
83 public Color getColor() { return color; }
84 public void setColor( Color color ) {
85 this.color = color;
86 }
87 public void draw( Graphics g ) {
88 if ( this.color != null ) g.setColor( this.color );
89 g.drawPolygon( this );
90 }
91 public void draw( Component c ) {
92 this.draw( c.getGraphics() );
93 }
94 public void fill( Graphics g ) {
95 if ( this.color != null ) g.setColor( this.color );
96 g.fillPolygon( this );
97 }
98 public void fill( Component c ) {
99 this.fill( c.getGraphics() );
100 }
101
102 /*
103 * Note: All rotation methods mutate the current polygon!
104 *
105 */
106
107 // rotate this polygon about the top lefthand corner
108 // of its bounding box:
109 public DrawablePolygon rotate( double theta ) {
110
111 // return the rotated polygon as a side effect:
112 return this.rotate( theta, new Point( this.getBounds().x,
113 this.getBounds().y ) );
114
115 }
116
117 // rotate this polygon about the center of its bounding box:
118 public DrawablePolygon centerRotate( double theta ) {
119
120 // compute the center of this polygon:
121 java.awt.Rectangle r = this.getBounds();
122 int x0 = r.x + r.width/2;
123 int y0 = r.y + r.height/2;
124
125 // return the rotated polygon as a side effect:
126 return this.rotate( theta, new Point( x0, y0 ) );
127
128 }
129
130 // rotate this polygon about an arbitrary point:
131 public DrawablePolygon rotate( double theta, Point p ) { // should this by DrawablePoint?
132 // things will break!
133 // local variables:
134 int x, y; DrawablePoint q;
135
136 // translate to the origin:
137 this.translate( -p.x, -p.y );
138
139 // rotate each vertex of this polygon:
140 for ( int i = 0; i < this.npoints; i++ ) {
141 x = this.xpoints[i]; y = this.ypoints[i];
142 q = new DrawablePoint( x, y );
143 q.rotate( theta );
144 this.xpoints[i] = q.x;
145 this.ypoints[i] = q.y;
146 }
147
148 // the bounding box is no longer valid:
149 this.bounds = null;
150
151 // translate back to original coordinates:
152 this.translate( p.x, p.y );
153
154 // return the rotated polygon as a side effect:
155 return this;
156
157 }
158
159 // overload Polygon.addPoint( int, int ):
160 public void addPoint( Point p ) { // should this be DrawablePoint?
161 super.addPoint( p.x, p.y ); // things will break!
162 }
163
164 // get all vertices of this polygon:
165 public Point[] getPoints() {
166
167 Point[] points = new Point[ npoints ];
168 for ( int i = 0; i < npoints; i++ ) {
169 points[i] = new Point( xpoints[i], ypoints[i] );
170 }
171 return points;
172
173 }
174
175 }