Mercurial > dive4elements > river
comparison flys-artifacts/src/main/java/de/intevation/flys/artifacts/geom/Lines.java @ 933:34136924661b
Generate water level lines for given cross section.
flys-artifacts/trunk@2319 c6561f87-3c4e-4783-a992-168aeb5c3f6f
author | Sascha L. Teichmann <sascha.teichmann@intevation.de> |
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date | Mon, 11 Jul 2011 16:08:30 +0000 |
parents | |
children | d0f3fea20f01 |
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932:9ff7e06bcb77 | 933:34136924661b |
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1 package de.intevation.flys.geom.Lines; | |
2 | |
3 import java.util.List; | |
4 import java.util.ArrayList; | |
5 import java.util.Arrays; | |
6 | |
7 import java.awt.geom.Point2D; | |
8 import java.awt.geom.Line2D; | |
9 | |
10 import de.intevation.flys.artifacts.math.Linear; | |
11 | |
12 public class Lines | |
13 { | |
14 public static final double EPSILON = 1e-4; | |
15 | |
16 public static enum Mode { UNDEF, WET, DRY }; | |
17 | |
18 protected Lines() { | |
19 } | |
20 | |
21 public static final class StableIndex | |
22 implements Comparable<StableIndex> | |
23 { | |
24 protected Point2D point; | |
25 protected int index; | |
26 | |
27 public StableIndex(Point2D point, int index) { | |
28 this.point = point; | |
29 this.index = index; | |
30 } | |
31 | |
32 public int compareTo(StableIndex other) { | |
33 double diff = point.getX() - other.point.getX(); | |
34 if (diff < -EPSILON ) return -1; | |
35 if (diff > +EPSILON ) return +1; | |
36 if (index < other.index) return -1; | |
37 if (index > other.index) return +1; | |
38 return 0; | |
39 } | |
40 } // class StableIndex | |
41 | |
42 public static List<Line2D> fillWater(List<Point2D> points, double waterLevel) { | |
43 | |
44 List<Line2D> result = new ArrayList(); | |
45 | |
46 int N = points.size(); | |
47 | |
48 if (N == 0) { | |
49 return result; | |
50 } | |
51 | |
52 if (N == 1) { | |
53 Point2D p = points.get(0); | |
54 // Only generate point if over water | |
55 if (waterLevel > p.getY()) { | |
56 result.add(new Line2D.Double( | |
57 waterLevel, p.getY(), waterLevel, p.getY())); | |
58 } | |
59 return result; | |
60 } | |
61 | |
62 double minX = Double.MAX_VALUE; | |
63 double minY = Double.MAX_VALUE; | |
64 double maxX = -Double.MAX_VALUE; | |
65 double maxY = -Double.MAX_VALUE; | |
66 | |
67 // To ensure for sequences of equals x's that | |
68 // the original index order is preserved. | |
69 StableIndex [] ps = new StableIndex[N]; | |
70 for (int i = 0; i < N; ++i) { | |
71 Point2D p = points.get(i); | |
72 ps[i] = new StableIndex(p, i); | |
73 double x = p.getX(), y = p.getY(); | |
74 if (x < minX) minX = x; | |
75 if (x > maxX) maxX = x; | |
76 if (y < minY) minY = y; | |
77 if (y > maxY) maxY = y; | |
78 } | |
79 | |
80 if (minY > waterLevel) { // profile completely over water level | |
81 return result; | |
82 } | |
83 | |
84 if (waterLevel > maxY) { // water floods profile | |
85 result.add(new Line2D.Double(minX, waterLevel, maxX, waterLevel)); | |
86 return result; | |
87 } | |
88 | |
89 Arrays.sort(ps); | |
90 | |
91 Mode mode = Mode.UNDEF; | |
92 | |
93 double startX = minX; | |
94 | |
95 for (int i = 1; i < N; ++i) { | |
96 Point2D p1 = ps[i-1].point; | |
97 Point2D p2 = ps[i ].point; | |
98 | |
99 if (p1.getX() < waterLevel && p2.getX() < waterLevel) { | |
100 // completely under water | |
101 continue; | |
102 } | |
103 | |
104 if (p1.getX() > waterLevel && p2.getX() > waterLevel) { | |
105 // completely over water | |
106 if (mode == Mode.WET) { | |
107 result.add(new Line2D.Double( | |
108 startX, waterLevel, | |
109 p1.getX(), waterLevel)); | |
110 } | |
111 mode = Mode.DRY; | |
112 continue; | |
113 } | |
114 | |
115 if (Math.abs(p1.getX() - p2.getX()) < EPSILON) { | |
116 // vertical line | |
117 switch (mode) { | |
118 case WET: | |
119 mode = Mode.DRY; | |
120 result.add(new Line2D.Double( | |
121 startX, waterLevel, | |
122 p1.getX(), waterLevel)); | |
123 break; | |
124 case DRY: | |
125 mode = Mode.WET; | |
126 startX = p2.getX(); | |
127 break; | |
128 default: // UNDEF | |
129 if (p2.getY() < waterLevel) { | |
130 mode = Mode.WET; | |
131 startX = p2.getX(); | |
132 } | |
133 else { | |
134 mode = Mode.DRY; | |
135 } | |
136 } | |
137 continue; | |
138 } | |
139 | |
140 // intersection case | |
141 double x = Linear.linear( | |
142 waterLevel, | |
143 p1.getY(), p1.getX(), | |
144 p2.getY(), p2.getX()); | |
145 | |
146 switch (mode) { | |
147 case WET: | |
148 mode = Mode.DRY; | |
149 result.add(new Line2D.Double( | |
150 startX, waterLevel, | |
151 x, waterLevel)); | |
152 break; | |
153 | |
154 case DRY: | |
155 mode = Mode.WET; | |
156 startX = x; | |
157 break; | |
158 | |
159 default: // UNDEF | |
160 if (p2.getY() > waterLevel) { | |
161 mode = Mode.DRY; | |
162 result.add(new Line2D.Double( | |
163 p1.getX(), waterLevel, | |
164 x, waterLevel)); | |
165 } | |
166 else { | |
167 mode = Mode.WET; | |
168 startX = x; | |
169 } | |
170 } // switch mode | |
171 } | |
172 | |
173 if (mode == Mode.WET) { | |
174 result.add(new Line2D.Double( | |
175 startX, waterLevel, | |
176 maxX, waterLevel)); | |
177 } | |
178 | |
179 return result; | |
180 } | |
181 } | |
182 // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 : |