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0a772436 GAPG |
1 | /******************************************************************************* |
2 | * Copyright (c) 2016 École Polytechnique de Montréal | |
3 | * | |
4 | * All rights reserved. This program and the accompanying materials are | |
5 | * made available under the terms of the Eclipse Public License v1.0 which | |
6 | * accompanies this distribution, and is available at | |
7 | * http://www.eclipse.org/legal/epl-v10.html | |
8 | *******************************************************************************/ | |
9 | ||
10 | package org.eclipse.tracecompass.internal.tmf.chart.ui.data; | |
11 | ||
12 | import static org.eclipse.tracecompass.common.core.NonNullUtils.checkNotNull; | |
13 | ||
14 | import java.math.BigDecimal; | |
15 | ||
16 | /** | |
17 | * Simple class that maps two {@link ChartRange} together. The first one is the | |
18 | * plotted range: it represents the range of the chart in which the data will be | |
19 | * plotted. The second one is the input data range: it represents the range of | |
20 | * the incoming data that will be plotted. | |
21 | * <p> | |
22 | * This map is used for mapping values that might be too big for a chart. Values | |
23 | * that are in the external range are mapped to fit the internal range. | |
24 | * | |
25 | * @author Gabriel-Andrew Pollo-Guilbert | |
26 | */ | |
27 | public class ChartRangeMap { | |
28 | ||
29 | // ------------------------------------------------------------------------ | |
30 | // Constants | |
31 | // ------------------------------------------------------------------------ | |
32 | ||
33 | private static final int BIG_DECIMAL_DIVISION_SCALE = 22; | |
34 | ||
35 | // ------------------------------------------------------------------------ | |
36 | // Members | |
37 | // ------------------------------------------------------------------------ | |
38 | ||
39 | private ChartRange fPlottedRange; | |
40 | private ChartRange fInputDataRange; | |
41 | ||
42 | // ------------------------------------------------------------------------ | |
43 | // Constructors | |
44 | // ------------------------------------------------------------------------ | |
45 | ||
46 | /** | |
47 | * Constructor. | |
48 | */ | |
49 | public ChartRangeMap() { | |
50 | fPlottedRange = new ChartRange(); | |
51 | fInputDataRange = new ChartRange(); | |
52 | } | |
53 | ||
54 | /** | |
55 | * Surcharged constructor with the input data range. | |
56 | * | |
57 | * @param input | |
58 | * The range of the input data | |
59 | */ | |
60 | public ChartRangeMap(ChartRange input) { | |
61 | fPlottedRange = new ChartRange(); | |
62 | fInputDataRange = input; | |
63 | } | |
64 | ||
65 | /** | |
66 | * Surcharged constructor with the plotted and input data ranges. | |
67 | * | |
68 | * @param plotted | |
69 | * The plotted range | |
70 | * @param input | |
71 | * The range of the input data | |
72 | */ | |
73 | public ChartRangeMap(ChartRange plotted, ChartRange input) { | |
74 | fPlottedRange = plotted; | |
75 | fInputDataRange = input; | |
76 | } | |
77 | ||
78 | // ------------------------------------------------------------------------ | |
79 | // Accessors | |
80 | // ------------------------------------------------------------------------ | |
81 | ||
82 | /** | |
83 | * Accessor that returns the plotted range of the map. | |
84 | * | |
85 | * @return The plotted range | |
86 | */ | |
87 | public ChartRange getPlottedRange() { | |
88 | return fPlottedRange; | |
89 | } | |
90 | ||
91 | /** | |
92 | * Accessor that returns the input data range of the map. | |
93 | * | |
94 | * @return The input data range | |
95 | */ | |
96 | public ChartRange getInputDataRange() { | |
97 | return fInputDataRange; | |
98 | } | |
99 | ||
100 | // ------------------------------------------------------------------------ | |
101 | // Mutators | |
102 | // ------------------------------------------------------------------------ | |
103 | ||
104 | /** | |
105 | * Mutator that sets the plotted range of the map. | |
106 | * | |
107 | * @param plotted | |
108 | * The new plotted range | |
109 | */ | |
110 | public void setPlottedRange(ChartRange plotted) { | |
111 | fPlottedRange = plotted; | |
112 | } | |
113 | ||
114 | /** | |
115 | * Mutator that sets the input data range of the map. | |
116 | * | |
117 | * @param input | |
118 | * The new input data range | |
119 | */ | |
120 | public void setInputDataRange(ChartRange input) { | |
121 | fInputDataRange = input; | |
122 | } | |
123 | ||
124 | // ------------------------------------------------------------------------ | |
125 | // Operations | |
126 | // ------------------------------------------------------------------------ | |
127 | ||
128 | /** | |
129 | * This method transforms a number from the input data range into a number | |
130 | * that fits in the plotted range. | |
131 | * <p> | |
132 | * Incoming numbers from the data might be bigger than the numbers that the | |
133 | * chart library supports (e.g. SWT supports Double and we can pass Long). | |
134 | * While processing the numbers, a loss of precision might occur. In order | |
135 | * to minimize this, we transform the raw values to an internal | |
136 | * representation based on a linear transformation. | |
137 | * <p> | |
138 | * Let <i>e_val</i>, <i>e_min</i>, <i>e_Δ</i> be the external value, | |
139 | * external minimum and external delta respectively and <i>i_min</i>, | |
140 | * <i>i_Δ</i> be the internal minimum and the internal delta. The internal | |
141 | * value <i>i_val</i> is given by the formula: | |
142 | * <p> | |
143 | * i_val=(e_val-e_min)*(i_Δ/e_Δ)+i_min | |
144 | * | |
145 | * @param number | |
146 | * A number to transform | |
147 | * @return The transformed value | |
148 | */ | |
149 | public Number getInternalValue(Number number) { | |
150 | BigDecimal value = new BigDecimal(number.toString()); | |
151 | ChartRange internal = getPlottedRange(); | |
152 | ChartRange external = getInputDataRange(); | |
153 | ||
154 | /* Apply the formula */ | |
155 | BigDecimal internalValue = value | |
156 | .subtract(external.getMinimum()) | |
157 | .multiply(internal.getDelta()) | |
158 | .divide(external.getDelta(), BIG_DECIMAL_DIVISION_SCALE, BigDecimal.ROUND_DOWN) | |
159 | .add(internal.getMinimum()); | |
160 | ||
161 | return checkNotNull(internalValue); | |
162 | } | |
163 | ||
164 | /** | |
165 | * Util method that transforms an plotted value back into its original | |
166 | * range. | |
167 | * <p> | |
168 | * It is very similar to {@link #getInternalValue(Number)}, except that is | |
169 | * apply the formula in reverse in order to obtain the original value while | |
170 | * minimizing lost in precision. | |
171 | * | |
172 | * @param number | |
173 | * A number to transform | |
174 | * @return A BigDecimal representation of the external value | |
175 | */ | |
176 | public BigDecimal getExternalValue(Number number) { | |
177 | ChartRange internal = getPlottedRange(); | |
178 | ChartRange external = getInputDataRange(); | |
179 | ||
180 | /* Apply the formula in reverse */ | |
181 | BigDecimal externalValue = (new BigDecimal(number.toString())) | |
182 | .subtract(internal.getMinimum()) | |
183 | .multiply(external.getDelta()) | |
184 | .divide(internal.getDelta(), BIG_DECIMAL_DIVISION_SCALE, BigDecimal.ROUND_DOWN) | |
185 | .add(external.getMinimum()); | |
186 | ||
187 | return checkNotNull(externalValue); | |
188 | } | |
189 | ||
190 | } |