1 package org.opentrafficsim.graphs;
2
3 import java.awt.Color;
4 import java.awt.Paint;
5
6 import org.jfree.chart.renderer.PaintScale;
7 import org.opentrafficsim.simulationengine.OTSSimulationException;
8
9 /**
10 * Create a continuous color paint scale. <br>
11 * Primarily intended for the contour plots, but sufficiently abstract for more general use. <br>
12 * A continuous color paint scale creates paints (actually simple Colors) by linearly interpolating between a limited set of RGB
13 * Color values that correspond to given input values.
14 * <p>
15 * Copyright (c) 2013-2015 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
16 * BSD-style license. See <a href="http://opentrafficsim.org/docs/license.html">OpenTrafficSim License</a>.
17 * <p>
18 * $LastChangedDate: 2015-07-26 01:01:13 +0200 (Sun, 26 Jul 2015) $, @version $Revision: 1155 $, by $Author: averbraeck $,
19 * initial version Jul 30, 2014 <br>
20 * @author <a href="http://www.tudelft.nl/pknoppers">Peter Knoppers</a>
21 */
22 public class ContinuousColorPaintScale implements PaintScale
23 {
24 /** Boundary values for this ColorPaintScale. */
25 private double[] bounds;
26
27 /** Color values to use at the boundary values. */
28 private Color[] boundColors;
29
30 /** Format string to render values in a human readable format (used in tool tip texts). */
31 private final String format;
32
33 /**
34 * Create a new ContinuousColorPaintScale.
35 * @param format Format string to render the value under the mouse in a human readable format
36 * @param bounds Double[] array of boundary values (all values must be distinct and the number of values must be >= 2)
37 * @param boundColors Color[] array of the colors to use at the boundary values (must have same size as bounds)
38 * @throws OTSSimulationException when bounds are wrong
39 */
40 ContinuousColorPaintScale(final String format, final double[] bounds, final Color[] boundColors)
41 throws OTSSimulationException
42 {
43 this.format = format;
44 if (bounds.length < 2)
45 {
46 throw new OTSSimulationException("bounds must have >= 2 entries");
47 }
48 if (bounds.length != boundColors.length)
49 {
50 throw new OTSSimulationException("bounds must have same length as boundColors");
51 }
52 this.bounds = new double[bounds.length];
53 this.boundColors = new Color[bounds.length];
54 // Store the bounds and boundColors in order of increasing bound value.
55 // This is as inefficient as bubble sorting, but we're dealing with only a few values here.
56 for (int nextBound = 0; nextBound < bounds.length; nextBound++)
57 {
58 // Find the lowest not-yet used bound
59 double currentLowest = Double.POSITIVE_INFINITY;
60 int bestIndex = -1;
61 int index;
62 for (index = 0; index < bounds.length; index++)
63 {
64 if (bounds[index] < currentLowest && (nextBound == 0 || bounds[index] > this.bounds[nextBound - 1]))
65 {
66 bestIndex = index;
67 currentLowest = bounds[index];
68 }
69 }
70 if (bestIndex < 0)
71 {
72 throw new OTSSimulationException("duplicate value in bounds");
73 }
74 this.bounds[nextBound] = bounds[bestIndex];
75 this.boundColors[nextBound] = boundColors[bestIndex];
76 }
77 }
78
79 /** {@inheritDoc} */
80 @Override
81 public final double getLowerBound()
82 {
83 return this.bounds[0];
84 }
85
86 /**
87 * Create a mixed color component. When ratio varies from 0.0 to 1.0, the result varies from <i>low</i> to <i>high</i>. If
88 * ratio is outside the range 0.0 to 1.0, the result value can be outside the <i>range</i> <i>low</i> to <i>high</i>.
89 * However, the result is always limited to the range 0..255.
90 * @param ratio Double; value (normally) between 0.0 and 1.0.
91 * @param low Integer; this value is returned when ratio equals 0.0
92 * @param high Integer; this value is returned when ratio equals 1.0
93 * @return Integer; the ratio-weighted average of <i>low</i> and <i>high</i>
94 */
95 private static int mixComponent(final double ratio, final int low, final int high)
96 {
97 final double mix = low * (1 - ratio) + high * ratio;
98 int result = (int) mix;
99 if (result < 0)
100 {
101 result = 0;
102 }
103 if (result > 255)
104 {
105 result = 255;
106 }
107 return result;
108 }
109
110 /** {@inheritDoc} */
111 @Override
112 public final Paint getPaint(final double value)
113 {
114 int bucket;
115 for (bucket = 0; bucket < this.bounds.length - 1; bucket++)
116 {
117 if (value < this.bounds[bucket + 1])
118 {
119 break;
120 }
121 }
122 if (bucket >= this.bounds.length - 1)
123 {
124 bucket = this.bounds.length - 2;
125 }
126 final double ratio = (value - this.bounds[bucket]) / (this.bounds[bucket + 1] - this.bounds[bucket]);
127 Color mix =
128 new Color(mixComponent(ratio, this.boundColors[bucket].getRed(), this.boundColors[bucket + 1].getRed()),
129 mixComponent(ratio, this.boundColors[bucket].getGreen(), this.boundColors[bucket + 1].getGreen()),
130 mixComponent(ratio, this.boundColors[bucket].getBlue(), this.boundColors[bucket + 1].getBlue()));
131 return mix;
132 }
133
134 /** {@inheritDoc} */
135 @Override
136 public final double getUpperBound()
137 {
138 return this.bounds[this.bounds.length - 1];
139 }
140
141 /**
142 * Retrieve the format string.
143 * @return format string
144 */
145 public final String getFormat()
146 {
147 return this.format;
148 }
149
150 }